Source for Campy CT chainrings? [Archive]

Dave Mayer

01-04-1970, 12:16 AM

"D'ohBoy" <petengail@yahoo.com> wrote in message
news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
>
> Hi, John -
>
> I hope you are aware that the Chorus and Record CT cranksets (and
> possibly the new Centaur Carbon CT) have one offset chainring bolt
> (112 mm bcd) making off the shelf non-oem chainrings an impossible
> fit.
>
> D'ohBoy
>

Correct, and the Centaur CT crankset also has custom rings. 4 of the bolts
are 110mm BCD. The fifth, that connects to the crankarm, is 112mm. I know:
bad, bad behaviour by Campagnolo. Normally I do not buy anything from a
company that goes out of its way to develop pointless proprietary standards.

But, I bought one of these cranksets (cheap) with the understanding that 5
minutes of filing with a small circular file would convert a standard
compact ring to the new 'Campy bolt circle standard'. I have done a lot
worse to bike parts.

This way I can run cheap 6-speed era Sugino rings in the inner position,
which I assume is what Campy was trying to prevent me from doing.

BTW: I also anticipate that I will have to install a slightly longer bolt
to attach the ring in the modified fifth hole.

John Verheul

01-04-1970, 12:16 AM

"D'ohBoy" <petengail@yahoo.com> wrote in message
news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
> John Verheul wrote:
>> Is anyone aware of a source (online, retail) for Campy compatible compact
>> chainrings? I think TA makes some that are much cheaper than Campy, but I
>> can't find them anywhere (I pretty much only need a 36t).
>>
>> Thanks in advance for any help.
>
> Hi, John -
>
> I hope you are aware that the Chorus and Record CT cranksets (and
> possibly the new Centaur Carbon CT) have one offset chainring bolt
> (112 mm bcd) making off the shelf non-oem chainrings an impossible
> fit.

It doesn't seem too hard to drill a single hole in a regular old (e.g - FSA
36t ring) compact ring that's 1mm farther from the center. The result would
make one existing hole look slightly "8" shaped.

Anyone think that's a crazy idea? Certainly seems worth a try...

Lou Holtman

01-04-1970, 12:16 AM

Tom Sherman wrote:
> D'ohBoy wrote:
>> John Verheul wrote:
>>> Is anyone aware of a source (online, retail) for Campy compatible
>>> compact
>>> chainrings? I think TA makes some that are much cheaper than Campy,
>>> but I
>>> can't find them anywhere (I pretty much only need a 36t).
>>>
>>> Thanks in advance for any help.
>>
>> Hi, John -
>>
>> I hope you are aware that the Chorus and Record CT cranksets (and
>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>> fit.
>
> And people complain about Shimano..., Sheesh!
>

I have a Record crankset, 5 years old 30000 km and no sign of wear. Cost
of chainrings on a roadbike is a non issue even at Campy pricelevels.

Lou

Tom Sherman

01-04-1970, 12:16 AM

Lou Holtman wrote:
> Tom Sherman wrote:
>> D'ohBoy wrote:
>>> ...
>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>> fit.
>>
>> And people complain about Shimano..., Sheesh!
>>
> I have a Record crankset, 5 years old 30000 km and no sign of wear. Cost
> of chainrings on a roadbike is a non issue even at Campy pricelevels.
>
The point is Shimano always gets grief for introducing new products that
are incompatible with older products and/or standards. Why should
Campagnolo get a pass for the same behavior? European Heritage &
Mystique, perhaps?

Remember who introduced 10-speed systems, which are much more expensive
for no real benefit for most riders?

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

Lou Holtman

01-04-1970, 12:16 AM

Tom Sherman wrote:
> Lou Holtman wrote:
>> Tom Sherman wrote:
>>> D'ohBoy wrote:
>>>> ...
>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>> fit.
>>>
>>> And people complain about Shimano..., Sheesh!
>>>
>> I have a Record crankset, 5 years old 30000 km and no sign of wear.
>> Cost of chainrings on a roadbike is a non issue even at Campy
>> pricelevels.
> >
> The point is Shimano always gets grief for introducing new products that
> are incompatible with older products and/or standards. Why should
> Campagnolo get a pass for the same behavior? European Heritage &
> Mystique, perhaps?

Huh? I bought the crankset 5 years ago and still can buy Campy
chainrings for that crankset. What is the problem? That TA doesn't make
any chainrings for that crankset?

>
> Remember who introduced 10-speed systems, which are much more expensive
> for no real benefit for most riders?

Nobody forces anybody to buy anything. You have choices. You make yours
, I make mine.
It is just complaining to complain. Silly...

Lou

Tom Ace

01-04-1970, 12:16 AM

On Jan 13, 7:47 am, Tom Sherman <sunsetss0...@REMOVETHISyahoo.com>
wrote:

> Remember who introduced 10-speed systems, which are much more expensive
> for no real benefit for most riders?

I love this line from a car review: "Remind me again why Lexus needs
an eight speed transmission? Oh yes; Mercedes has a seven speed."
http://www.thetruthaboutcars.com/reviews/lexus-ls-460/

Tom Ace

Tom Sherman

01-04-1970, 12:16 AM

Lou Holtman wrote:
> Tom Sherman wrote:
>> Lou Holtman wrote:
>>> Tom Sherman wrote:
>>>> D'ohBoy wrote:
>>>>> ...
>>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>>> fit.
>>>>
>>>> And people complain about Shimano..., Sheesh!
>>>>
>>> I have a Record crankset, 5 years old 30000 km and no sign of wear.
>>> Cost of chainrings on a roadbike is a non issue even at Campy
>>> pricelevels.
>> >
>> The point is Shimano always gets grief for introducing new products
>> that are incompatible with older products and/or standards. Why should
>> Campagnolo get a pass for the same behavior? European Heritage &
>> Mystique, perhaps?
>
> Huh? I bought the crankset 5 years ago and still can buy Campy
> chainrings for that crankset. What is the problem? That TA doesn't make
> any chainrings for that crankset?
>
The problem is that the crank has been made non-compatible with standard
chainrings for no good reason.

This is bad behavior on Campagnolo's part, unless the cranks come with a
prominent warning of their in-compatibility with normal chain rings.
>
>> Remember who introduced 10-speed systems, which are much more
>> expensive for no real benefit for most riders?
>
> Nobody forces anybody to buy anything. You have choices. You make yours
> , I make mine.
> It is just complaining to complain. Silly...
>
Why does "Big C" get a pass, when "Big S" does not on these matters?

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

Lou Holtman

01-04-1970, 12:16 AM

Tom Sherman wrote:
> Lou Holtman wrote:
>> Tom Sherman wrote:
>>> Lou Holtman wrote:
>>>> Tom Sherman wrote:
>>>>> D'ohBoy wrote:
>>>>>> ...
>>>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>>>> fit.
>>>>>
>>>>> And people complain about Shimano..., Sheesh!
>>>>>
>>>> I have a Record crankset, 5 years old 30000 km and no sign of wear.
>>>> Cost of chainrings on a roadbike is a non issue even at Campy
>>>> pricelevels.
>>> >
>>> The point is Shimano always gets grief for introducing new products
>>> that are incompatible with older products and/or standards. Why
>>> should Campagnolo get a pass for the same behavior? European Heritage
>>> & Mystique, perhaps?
>>
>> Huh? I bought the crankset 5 years ago and still can buy Campy
>> chainrings for that crankset. What is the problem? That TA doesn't
>> make any chainrings for that crankset?
> >
> The problem is that the crank has been made non-compatible with standard
> chainrings for no good reason.

So what. If you don't like it, don't buy it.

>
> This is bad behavior on Campagnolo's part, unless the cranks come with a
> prominent warning of their in-compatibility with normal chain rings.

People must understand that C and S are commercial companies that try to
make a profit. If you realize that, you know that you have to inform
yourself. Prominent warning from Campagnolo? Come on get real.

>>> Remember who introduced 10-speed systems, which are much more
>>> expensive for no real benefit for most riders?
>>
>> Nobody forces anybody to buy anything. You have choices. You make
>> yours , I make mine.
>> It is just complaining to complain. Silly...
> >
> Why does "Big C" get a pass, when "Big S" does not on these matters?

Who cares? I don't.

Lou

D'ohBoy

01-04-1970, 12:16 AM

Tom Sherman wrote, in part:

> Why does "Big C" get a pass, when "Big S" does not on these matters?
>

Despite my knowledge of the 112 bcd bolt on the Campagnolo cranks, I
have purchased two of them and haven't looked back.

Yah, they got ya by the short hairs for chainrings but they ARE quite
nice and durable (and expensive).

D'ohBoy

Tom Sherman

01-04-1970, 12:16 AM

jim beam

01-04-1970, 12:16 AM

Tom Ace wrote:
> On Jan 13, 7:47 am, Tom Sherman <sunsetss0...@REMOVETHISyahoo.com>
> wrote:
>
>> Remember who introduced 10-speed systems, which are much more expensive
>> for no real benefit for most riders?
>
> I love this line from a car review: "Remind me again why Lexus needs
> an eight speed transmission? Oh yes; Mercedes has a seven speed."
> http://www.thetruthaboutcars.com/reviews/lexus-ls-460/
>

wow, the disillusionment and paranoia on this group is spectacular.
particularly when fed by insufficient understanding.

the truth is, engines are fuel efficient in relatively narrow rev
ranges. if you want better fuel economy, use more gears.

the extreme example is continuously variable transmission [cvt] -
something very popular for small cars in countries outside north
america. [why it's not popular inside north america is a whole
different topic.] it's even been sold on some cars here, subaru and
honda spring to mind, and is very reliable. the 96-2000 honda civic hx
for example can routinely achieve 55mpg, somewhat better than the
current honda civic hybrid. [it achieves this by keeping revs very
narrowly confined and varying the transmission ratio by tiny increments
to match speed.]

for higher torque associated with big heavy luxury cars however, cvt
doesn't measure up, hence a higher number of conventional gears. oh,
and if you want speed/power, you can keep the revs up near peak output
much better with more gears too.

Ben C

01-04-1970, 12:16 AM

On 2008-01-13, jim beam <spamvortex@bad.example.net> wrote:
> Tom Ace wrote:
>> On Jan 13, 7:47 am, Tom Sherman <sunsetss0...@REMOVETHISyahoo.com>
>> wrote:
>>
>>> Remember who introduced 10-speed systems, which are much more expensive
>>> for no real benefit for most riders?
>>
>> I love this line from a car review: "Remind me again why Lexus needs
>> an eight speed transmission? Oh yes; Mercedes has a seven speed."
>> http://www.thetruthaboutcars.com/reviews/lexus-ls-460/
>>
>
> wow, the disillusionment and paranoia on this group is spectacular.
> particularly when fed by insufficient understanding.
>
> the truth is, engines are fuel efficient in relatively narrow rev
> ranges. if you want better fuel economy, use more gears.
>
> the extreme example is continuously variable transmission [cvt] -
> something very popular for small cars in countries outside north
> america. [why it's not popular inside north america is a whole
> different topic.] it's even been sold on some cars here, subaru and
> honda spring to mind, and is very reliable. the 96-2000 honda civic hx
> for example can routinely achieve 55mpg, somewhat better than the
> current honda civic hybrid.

The hybrid probably also has a kind of CVT, assuming it has a system
similar to that on the Prius, which uses its two electric
motor/generators in clever ways to achieve CVT without the use of rubber
belts.

It's a single planetary gear system basically set up for top gear.
Engine is connected to the planet-carrier, the road wheels and one MG
(motor/generator) to the crown wheel, the other MG to the sun. To lower
the gear ratio you spin up the sun wheel with an electric motor which is
drawing power from the generator on the crown wheel. Something like that
anyway, the details are easy to get wrong.

Various combinations of bump-starting, electric reversing (reversing is
always electric-only on the Prius) are possible by changing the
directions of things in clever ways.

> [it achieves this by keeping revs very
> narrowly confined and varying the transmission ratio by tiny increments
> to match speed.]
>
> for higher torque associated with big heavy luxury cars however, cvt
> doesn't measure up, hence a higher number of conventional gears.

That's why hybrid luxury cars are quite an interesting option-- because
you can have CVT on them without the problem of too much torque for the
rubber belts. And you get pretty good acceleration running the V6 and
electric motor in parallel.

Tom Sherman

01-04-1970, 12:16 AM

"jim beam" wrote:
> Tom Ace wrote:
>> On Jan 13, 7:47 am, Tom Sherman <sunsetss0...@REMOVETHISyahoo.com>
>> wrote:
>>
>>> Remember who introduced 10-speed systems, which are much more expensive
>>> for no real benefit for most riders?
>>
>> I love this line from a car review: "Remind me again why Lexus needs
>> an eight speed transmission? Oh yes; Mercedes has a seven speed."
>> http://www.thetruthaboutcars.com/reviews/lexus-ls-460/
>>
>
> wow, the disillusionment and paranoia on this group is spectacular.
> particularly when fed by insufficient understanding.
>
> the truth is, engines are fuel efficient in relatively narrow rev
> ranges. if you want better fuel economy, use more gears.
>
> the extreme example is continuously variable transmission [cvt] -
> something very popular for small cars in countries outside north
> america. [why it's not popular inside north america is a whole
> different topic.] it's even been sold on some cars here, subaru and
> honda spring to mind, and is very reliable. the 96-2000 honda civic hx
> for example can routinely achieve 55mpg, somewhat better than the
> current honda civic hybrid. [it achieves this by keeping revs very
> narrowly confined and varying the transmission ratio by tiny increments
> to match speed.]...

butbutbut, the standard manual transmission is much more fun on a Honda
Civic! I find that I shift more than necessary for the heck of it - the
way the lever moves into the next gear with perfect rpm matching during
a double-clutch shift is addictive.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

Tom Sherman

01-04-1970, 12:16 AM

Lou Holtman wrote:
> Tom Sherman wrote:
>> Lou Holtman wrote:
>>> Tom Sherman wrote:
>>>> Lou Holtman wrote:
>>>>> Tom Sherman wrote:
>>>>>> D'ohBoy wrote:
>>>>>>> ...
>>>>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>>>>> fit.
>>>>>>
>>>>>> And people complain about Shimano..., Sheesh!
>>>>>>
>>>>> I have a Record crankset, 5 years old 30000 km and no sign of wear.
>>>>> Cost of chainrings on a roadbike is a non issue even at Campy
>>>>> pricelevels.
>>>> >
>>>> The point is Shimano always gets grief for introducing new products
>>>> that are incompatible with older products and/or standards. Why
>>>> should Campagnolo get a pass for the same behavior? European
>>>> Heritage & Mystique, perhaps?
>>>
>>> Huh? I bought the crankset 5 years ago and still can buy Campy
>>> chainrings for that crankset. What is the problem? That TA doesn't
>>> make any chainrings for that crankset?
>> >
>> The problem is that the crank has been made non-compatible with
>> standard chainrings for no good reason.
>
> So what. If you don't like it, don't buy it.
>
I would not buy it (the crank) if I was aware of the deliberate action
to create incompatibility.
>
>>
>> This is bad behavior on Campagnolo's part, unless the cranks come with
>> a prominent warning of their in-compatibility with normal chain rings.
>
> People must understand that C and S are commercial companies that try to
> make a profit. If you realize that, you know that you have to inform
> yourself. Prominent warning from Campagnolo? Come on get real.
>
Wanting to make a profit does not excuse the behavior. Campagnolo or
Shimano can still make a profit without resorting to tactics that are
NOT in the interests of their customers.
>
>>>> Remember who introduced 10-speed systems, which are much more
>>>> expensive for no real benefit for most riders?
>>>
>>> Nobody forces anybody to buy anything. You have choices. You make
>>> yours , I make mine.
>>> It is just complaining to complain. Silly...
>> >
>> Why does "Big C" get a pass, when "Big S" does not on these matters?
>
> Who cares? I don't.
>
To judge by past postings, quite a few people do care (and rightfully so).

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

Tom Sherman

01-04-1970, 12:16 AM

Dave Mayer wrote:
> "D'ohBoy" <petengail@yahoo.com> wrote in message
> news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
>> Hi, John -
>>
>> I hope you are aware that the Chorus and Record CT cranksets (and
>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>> fit.
>
> Correct, and the Centaur CT crankset also has custom rings. 4 of the bolts
> are 110mm BCD. The fifth, that connects to the crankarm, is 112mm. I know:
> bad, bad behaviour by Campagnolo. Normally I do not buy anything from a
> company that goes out of its way to develop pointless proprietary standards.
>
A very sensible position to take.
>
> But, I bought one of these cranksets (cheap) with the understanding that 5
> minutes of filing with a small circular file would convert a standard
> compact ring to the new 'Campy bolt circle standard'. I have done a lot
> worse to bike parts.
>
> This way I can run cheap 6-speed era Sugino rings in the inner position,
> which I assume is what Campy was trying to prevent me from doing.
>
> BTW: I also anticipate that I will have to install a slightly longer bolt
> to attach the ring in the modified fifth hole.
>
Way to beat the "man"! :)

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

M-gineering

01-04-1970, 12:16 AM

Tom Sherman wrote:
> Dave Mayer wrote:
>> "D'ohBoy" <petengail@yahoo.com> wrote in message
>> news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
>>> Hi, John -
>>>
>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>> fit.
>>
>> Correct, and the Centaur CT crankset also has custom rings. 4 of the
>> bolts are 110mm BCD. The fifth, that connects to the crankarm, is
>> 112mm. I know: bad, bad behaviour by Campagnolo. Normally I do not
>> buy anything from a company that goes out of its way to develop
>> pointless proprietary standards.

TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39
and 48. 49,50 & 52T

--
/Marten

info(apestaartje)m-gineering(punt)nl

Lou Holtman

01-04-1970, 12:16 AM

M-gineering wrote:
> Tom Sherman wrote:
>> Dave Mayer wrote:
>>> "D'ohBoy" <petengail@yahoo.com> wrote in message
>>> news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
>>>
>>>> Hi, John -
>>>>
>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>> fit.
>>>
>>> Correct, and the Centaur CT crankset also has custom rings. 4 of the
>>> bolts are 110mm BCD. The fifth, that connects to the crankarm, is
>>> 112mm. I know: bad, bad behaviour by Campagnolo. Normally I do not
>>> buy anything from a company that goes out of its way to develop
>>> pointless proprietary standards.
>
>
> TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39
> and 48. 49,50 & 52T
>

There you go. Complaining about nothing. If the installed base is large
enough third parties will offer replacement to make some profit to. So
people buy Campy CT cranksets. Do it for Tom ;-)

Lou

John Verheul

01-04-1970, 12:16 AM

"M-gineering" <ikmotgeenspam@m-gineering.nl> wrote in message
news:fmdhsl$74r$1@localhost.localdomain...
> TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39 and
> 48. 49,50 & 52T

Wonderful, where does one find these animals?

Tom Sherman

01-04-1970, 12:16 AM

Lou Holtman wrote:
> M-gineering wrote:
>> Tom Sherman wrote:
>>> Dave Mayer wrote:
>>>> "D'ohBoy" <petengail@yahoo.com> wrote in message
>>>> news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
>>>>
>>>>> Hi, John -
>>>>>
>>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>>> fit.
>>>>
>>>> Correct, and the Centaur CT crankset also has custom rings. 4 of
>>>> the bolts are 110mm BCD. The fifth, that connects to the crankarm,
>>>> is 112mm. I know: bad, bad behaviour by Campagnolo. Normally I do
>>>> not buy anything from a company that goes out of its way to develop
>>>> pointless proprietary standards.
>>
>>
>> TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39
>> and 48. 49,50 & 52T
>
> There you go. Complaining about nothing. If the installed base is large
> enough third parties will offer replacement to make some profit to. So
> people buy Campy CT cranksets. Do it for Tom ;-)

Even if third parties offer compatible rings, that means that additional
tooling, stocking and distribution costs. Therefore, these particular
chainrings (or chainrings in general) are more expensive to the consumer
than they need to be for a given quality. Availability will also be
poorer, since it mean another item for seller's to stock and tie up
funds in - just what the LBS does NOT need.

The only legitimate reason for a manufacturer to deviate from a standard
is if that deviation provides substantial advantages elsewhere.
Offsetting one (1) chainring bolt does not meet that criterion.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

Michael Press

01-04-1970, 12:16 AM

In article
<478a5352$0$25496$9a622dc7@news.kpnplanet.nl>,
Lou Holtman <lholremovethis@planet.nl> wrote:

> M-gineering wrote:
> > Tom Sherman wrote:
> >> Dave Mayer wrote:
> >>> "D'ohBoy" <petengail@yahoo.com> wrote in message
> >>> news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
> >>>
> >>>> Hi, John -
> >>>>
> >>>> I hope you are aware that the Chorus and Record CT cranksets (and
> >>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
> >>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
> >>>> fit.
> >>>
> >>> Correct, and the Centaur CT crankset also has custom rings. 4 of the
> >>> bolts are 110mm BCD. The fifth, that connects to the crankarm, is
> >>> 112mm. I know: bad, bad behaviour by Campagnolo. Normally I do not
> >>> buy anything from a company that goes out of its way to develop
> >>> pointless proprietary standards.
> >
> >
> > TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39
> > and 48. 49,50 & 52T
> >
>
>
> There you go. Complaining about nothing. If the installed base is large
> enough third parties will offer replacement to make some profit to. So
> people buy Campy CT cranksets. Do it for Tom ;-)

That is third party singular. TA makes their business
manufacturing high quality chainrings for all configurations;
as well as cranksets.

--
Michael Press

Gary Young

01-04-1970, 12:17 AM

On Sun, 13 Jan 2008 12:30:24 -0600, Tom Sherman wrote:

> Lou Holtman wrote:
>> M-gineering wrote:
>>> Tom Sherman wrote:
>>>> Dave Mayer wrote:
>>>>> "D'ohBoy" <petengail@yahoo.com> wrote in message
>>>>>
news:9051bfa0-0795-4cfc-81f8-05da18caf3fe@e25g2000prg.googlegroups.com...
>>>>>
>>>>>> Hi, John -
>>>>>>
>>>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>>>> fit.
>>>>>
>>>>> Correct, and the Centaur CT crankset also has custom rings. 4 of
>>>>> the bolts are 110mm BCD. The fifth, that connects to the crankarm,
>>>>> is 112mm. I know: bad, bad behaviour by Campagnolo. Normally I do
>>>>> not buy anything from a company that goes out of its way to develop
>>>>> pointless proprietary standards.
>>>
>>>
>>> TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39
>>> and 48. 49,50 & 52T
>>
>> There you go. Complaining about nothing. If the installed base is large
>> enough third parties will offer replacement to make some profit to. So
>> people buy Campy CT cranksets. Do it for Tom ;-)
>
> Even if third parties offer compatible rings, that means that additional
> tooling, stocking and distribution costs. Therefore, these particular
> chainrings (or chainrings in general) are more expensive to the consumer
> than they need to be for a given quality. Availability will also be
> poorer, since it mean another item for seller's to stock and tie up
> funds in - just what the LBS does NOT need.
>
> The only legitimate reason for a manufacturer to deviate from a standard
> is if that deviation provides substantial advantages elsewhere.
> Offsetting one (1) chainring bolt does not meet that criterion.

Campy might be able to argue that the offset bolt is a quality-control
measure -- maybe it ensures that the ramps and pins line up properly
between the big and small chainring. That way Campy doesn't have to deal
with complaints from consumers who don't know how to install the
chainrings properly. I'm not saying that is the real reason (for one
thing, I don't use Campy cranks -- the 135mm bolt circle is enough to put
me off), but it's a possibility that no one here seems to have considered.

A Muzi

01-04-1970, 12:17 AM

>>>>> "D'ohBoy" <petengail@yahoo.com> wrote
>>>>>> I hope you are aware that the Chorus and Record CT cranksets (and
>>>>>> possibly the new Centaur Carbon CT) have one offset chainring bolt
>>>>>> (112 mm bcd) making off the shelf non-oem chainrings an impossible
>>>>>> fit.

>>>> Dave Mayer wrote:
>>>>> Correct, and the Centaur CT crankset also has custom rings. 4 of
>>>>> the bolts are 110mm BCD. The fifth, that connects to the crankarm,
>>>>> is 112mm. I know: bad, bad behaviour by Campagnolo. Normally I do
>>>>> not buy anything from a company that goes out of its way to develop
>>>>> pointless proprietary standards.

>> M-gineering wrote:
>>> TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39
>>> and 48. 49,50 & 52T

> Lou Holtman wrote:
>> There you go. Complaining about nothing. If the installed base is
>> large enough third parties will offer replacement to make some profit
>> to. So people buy Campy CT cranksets. Do it for Tom ;-)

Tom Sherman wrote:
> Even if third parties offer compatible rings, that means that additional
> tooling, stocking and distribution costs. Therefore, these particular
> chainrings (or chainrings in general) are more expensive to the consumer
> than they need to be for a given quality. Availability will also be
> poorer, since it mean another item for seller's to stock and tie up
> funds in - just what the LBS does NOT need.
> The only legitimate reason for a manufacturer to deviate from a standard
> is if that deviation provides substantial advantages elsewhere.
> Offsetting one (1) chainring bolt does not meet that criterion.

Or maybe it's to assure manufacturer's designed position of ramps/pins?

And hey, 110mm cranks are not exactly exotic animals. If you don't like
the carbon 110/112, there are a gazillion 110 aluminum cranks out there.
Choice is good. So for riders who intend a 38-44, maybe a Campagnolo
Carbon CT isn't a great choice. If you intend 36-50 why worry?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

M-gineering

01-04-1970, 12:17 AM

Gary Young wrote:

> Campy might be able to argue that the offset bolt is a quality-control
> measure -- maybe it ensures that the ramps and pins line up properly
> between the big and small chainring. That way Campy doesn't have to deal
> with complaints from consumers who don't know how to install the
> chainrings properly. I'm not saying that is the real reason (for one
> thing, I don't use Campy cranks -- the 135mm bolt circle is enough to put
> me off), but it's a possibility that no one here seems to have considered.

given the complexity of their chain installation procedures I don't
think making things easy was on their mind ;)
--
/Marten

info(apestaartje)m-gineering(punt)nl

Donald Gillies

01-04-1970, 12:18 AM

"John Verheul" <vjohn1020@qwest.net> writes:

>"M-gineering" <ikmotgeenspam@m-gineering.nl> wrote in message
>news:fmdhsl$74r$1@localhost.localdomain...
>> TA offers Nerius chainrings for CAmpagnolo compact in 34, 36, 38 & 39 and
>> 48. 49,50 & 52T

>Wonderful, where does one find these animals?

www.xxcycle.com ?? I hope you are prepared to wait 6 months for the
european mails to arrive ...

- Don Gillies
San Diego, CA

jim beam

01-04-1970, 12:21 AM

Ben C wrote:
> On 2008-01-13, jim beam <spamvortex@bad.example.net> wrote:
>> Tom Ace wrote:
>>> On Jan 13, 7:47 am, Tom Sherman <sunsetss0...@REMOVETHISyahoo.com>
>>> wrote:
>>>
>>>> Remember who introduced 10-speed systems, which are much more expensive
>>>> for no real benefit for most riders?
>>> I love this line from a car review: "Remind me again why Lexus needs
>>> an eight speed transmission? Oh yes; Mercedes has a seven speed."
>>> http://www.thetruthaboutcars.com/reviews/lexus-ls-460/
>>>
>> wow, the disillusionment and paranoia on this group is spectacular.
>> particularly when fed by insufficient understanding.
>>
>> the truth is, engines are fuel efficient in relatively narrow rev
>> ranges. if you want better fuel economy, use more gears.
>>
>> the extreme example is continuously variable transmission [cvt] -
>> something very popular for small cars in countries outside north
>> america. [why it's not popular inside north america is a whole
>> different topic.] it's even been sold on some cars here, subaru and
>> honda spring to mind, and is very reliable. the 96-2000 honda civic hx
>> for example can routinely achieve 55mpg, somewhat better than the
>> current honda civic hybrid.
>
> The hybrid probably also has a kind of CVT, assuming it has a system
> similar to that on the Prius, which uses its two electric
> motor/generators in clever ways to achieve CVT without the use of rubber
> belts.
>
> It's a single planetary gear system basically set up for top gear.
> Engine is connected to the planet-carrier, the road wheels and one MG
> (motor/generator) to the crown wheel, the other MG to the sun. To lower
> the gear ratio you spin up the sun wheel with an electric motor which is
> drawing power from the generator on the crown wheel. Something like that
> anyway, the details are easy to get wrong.

that would be an interesting way of doing it. the honda and subaru
cvt's are similar to the ones i believe you had in europe back in the
70's & 80's with daf & volvo - two variable cones and a belt.

>
> Various combinations of bump-starting, electric reversing (reversing is
> always electric-only on the Prius) are possible by changing the
> directions of things in clever ways.
>
>> [it achieves this by keeping revs very
>> narrowly confined and varying the transmission ratio by tiny increments
>> to match speed.]
>>
>> for higher torque associated with big heavy luxury cars however, cvt
>> doesn't measure up, hence a higher number of conventional gears.
>
> That's why hybrid luxury cars are quite an interesting option-- because
> you can have CVT on them without the problem of too much torque for the
> rubber belts.

honda and subaru use steel belts. don't euro-ford and fiat have cvt
with steel belts too?

> And you get pretty good acceleration running the V6 and
> electric motor in parallel.

you can get great acceleration just on the electric motors!

Ben C

01-04-1970, 12:24 AM

On 2008-01-15, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
> "jim beam" wrote:
[...]
>> the extreme example is continuously variable transmission [cvt] -
>> something very popular for small cars in countries outside north
>> america. [why it's not popular inside north america is a whole
>> different topic.] it's even been sold on some cars here, subaru and
>> honda spring to mind, and is very reliable. the 96-2000 honda civic hx
>> for example can routinely achieve 55mpg, somewhat better than the
>> current honda civic hybrid. [it achieves this by keeping revs very
>> narrowly confined and varying the transmission ratio by tiny increments
>> to match speed.]...
>
> butbutbut, the standard manual transmission is much more fun on a Honda
> Civic! I find that I shift more than necessary for the heck of it - the
> way the lever moves into the next gear with perfect rpm matching during
> a double-clutch shift is addictive.

It's all right they thought of people like you. CVT cars often have a
manual mode where you get to choose between 6 "virtual ratios" with a
sequential action on the gearlever.

A BMW with CVT I drove once had that (it was the BMW "Mini"). It was a
bit pointless though, the proper CVT was much better.

I don't think it played a wav file of double-declutching noises, but
that should be an easy modification.

Ben C

01-04-1970, 12:25 AM

On 2008-01-15, jim beam <spamvortex@bad.example.net> wrote:
> Ben C wrote:
[...]
>> That's why hybrid luxury cars are quite an interesting option-- because
>> you can have CVT on them without the problem of too much torque for the
>> rubber belts.
>
> honda and subaru use steel belts. don't euro-ford and fiat have cvt
> with steel belts too?

I think you're right they are steel.

Wikipedia says: "In the summer of 1987 the Ford Fiesta and Fiat Uno
became the first mainstream European cars to be equipped with
steel-belted CVT (as opposed to the less robust rubber-belted DAF
design). This CVT, the Ford CTX was developed by Ford, Van Doorne, and
Fiat, with work on the transmission starting in 1976"

Quite good page about CVT: http://auto.howstuffworks.com/cvt2.htm

Doesn't mention the Prius so-called "E-CVT" or "PSD".

jim beam

01-04-1970, 12:26 AM

Ben C wrote:
> On 2008-01-15, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> "jim beam" wrote:
> [...]
>>> the extreme example is continuously variable transmission [cvt] -
>>> something very popular for small cars in countries outside north
>>> america. [why it's not popular inside north america is a whole
>>> different topic.] it's even been sold on some cars here, subaru and
>>> honda spring to mind, and is very reliable. the 96-2000 honda civic hx
>>> for example can routinely achieve 55mpg, somewhat better than the
>>> current honda civic hybrid. [it achieves this by keeping revs very
>>> narrowly confined and varying the transmission ratio by tiny increments
>>> to match speed.]...
>> butbutbut, the standard manual transmission is much more fun on a Honda
>> Civic! I find that I shift more than necessary for the heck of it - the
>> way the lever moves into the next gear with perfect rpm matching during
>> a double-clutch shift is addictive.
>
> It's all right they thought of people like you. CVT cars often have a
> manual mode where you get to choose between 6 "virtual ratios" with a
> sequential action on the gearlever.
>
> A BMW with CVT I drove once had that (it was the BMW "Mini"). It was a
> bit pointless though, the proper CVT was much better.

"a bit pointless"??? its retardation blows my freakin' mind!!! cvt is
brilliant - i've driven it and loved it. but the masses, whether their
expectations are misled by the sales droids or not, "want" the "feel" of
distinct ratios. it's utterly illogical and negates the whole point.

>
> I don't think it played a wav file of double-declutching noises, but
> that should be an easy modification.

given the above, probably a necessary one.

Ben C

01-04-1970, 12:27 AM

On 2008-01-15, jim beam <spamvortex@bad.example.net> wrote:
> Ben C wrote:
>> On 2008-01-15, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> "jim beam" wrote:
[...]
>>> butbutbut, the standard manual transmission is much more fun on a Honda
>>> Civic! I find that I shift more than necessary for the heck of it - the
>>> way the lever moves into the next gear with perfect rpm matching during
>>> a double-clutch shift is addictive.
>>
>> It's all right they thought of people like you. CVT cars often have a
>> manual mode where you get to choose between 6 "virtual ratios" with a
>> sequential action on the gearlever.
>>
>> A BMW with CVT I drove once had that (it was the BMW "Mini"). It was a
>> bit pointless though, the proper CVT was much better.
>
> "a bit pointless"??? its retardation blows my freakin' mind!!! cvt is
> brilliant - i've driven it and loved it. but the masses, whether their
> expectations are misled by the sales droids or not, "want" the "feel" of
> distinct ratios. it's utterly illogical and negates the whole point.

True, but it costs the price of a switch and probably 100 lines of
computer code, and might sell more cars.

The actual CVT is quite interesting-- I never quite figured out how it
decided what gear ratio to give you based on how aggressively you pushed
the (probably by-wire) throttle. I was expecting it to drone along
comfortably at more or less constant revs but that's not how they set it
up.

As far as I can remember it was more like a conventional auto but
continuous-- push the throttle and the revs rise, but hold it there, and
the gear ratio smoothly catches up until you're doing about 2.5k rpm.
Lift off a bit and perhaps it catches up a bit more quickly. You get a
sort of "kickdown" if you floor it, where it keeps revving up to about
6k, and then pretty much stays at 6k increasing the gear ratio as your
speed increases.

You get a "Sport" mode and some sort of regular mode. But it felt like
maybe you should have had a knob to turn to interpolate between the two.
Perhaps a third (optional of course) "rev" pedal would be a good
solution.

jim beam

01-04-1970, 12:27 AM

Ben C wrote:
> On 2008-01-15, jim beam <spamvortex@bad.example.net> wrote:
>> Ben C wrote:
>>> On 2008-01-15, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> "jim beam" wrote:
> [...]
>>>> butbutbut, the standard manual transmission is much more fun on a Honda
>>>> Civic! I find that I shift more than necessary for the heck of it - the
>>>> way the lever moves into the next gear with perfect rpm matching during
>>>> a double-clutch shift is addictive.
>>> It's all right they thought of people like you. CVT cars often have a
>>> manual mode where you get to choose between 6 "virtual ratios" with a
>>> sequential action on the gearlever.
>>>
>>> A BMW with CVT I drove once had that (it was the BMW "Mini"). It was a
>>> bit pointless though, the proper CVT was much better.
>> "a bit pointless"??? its retardation blows my freakin' mind!!! cvt is
>> brilliant - i've driven it and loved it. but the masses, whether their
>> expectations are misled by the sales droids or not, "want" the "feel" of
>> distinct ratios. it's utterly illogical and negates the whole point.
>
> True, but it costs the price of a switch and probably 100 lines of
> computer code, and might sell more cars.

but it defeats the whole point of bothering with cvt in the first place!
and it'll cause uneven wear on the cones.

>
> The actual CVT is quite interesting-- I never quite figured out how it
> decided what gear ratio to give you based on how aggressively you pushed
> the (probably by-wire) throttle. I was expecting it to drone along
> comfortably at more or less constant revs but that's not how they set it
> up.
>
> As far as I can remember it was more like a conventional auto but
> continuous-- push the throttle and the revs rise, but hold it there, and
> the gear ratio smoothly catches up until you're doing about 2.5k rpm.
> Lift off a bit and perhaps it catches up a bit more quickly. You get a
> sort of "kickdown" if you floor it, where it keeps revving up to about
> 6k, and then pretty much stays at 6k increasing the gear ratio as your
> speed increases.
>
> You get a "Sport" mode and some sort of regular mode. But it felt like
> maybe you should have had a knob to turn to interpolate between the two.
> Perhaps a third (optional of course) "rev" pedal would be a good
> solution.

the one i drove was a daf back from the 70's. control was mechanical
with vacuum servos. not a sophisticated system, but it worked just
great. it had something like a 650cc 2-cylinder motor, but because it
was always perfectly geared, it was like a rocket off the line and would
cruise at a steady 80 no problems. great in snow too because it had two
drive belts, effectively acting like a limited slip diff. had a switch
on the dash that you had to press to get it to do engine braking. a
strange beast, but like i said, it was a very useful system and utilized
that puny little engine most effectively.

Ben C

01-04-1970, 12:30 AM

On 2008-01-16, jim beam <spamvortex@bad.example.net> wrote:
> Ben C wrote:
>> On 2008-01-15, jim beam <spamvortex@bad.example.net> wrote:
>>> Ben C wrote:
[...]
>>>> manual mode where you get to choose between 6 "virtual ratios" with a
>>>> sequential action on the gearlever.
>>>>
>>>> A BMW with CVT I drove once had that (it was the BMW "Mini"). It was a
>>>> bit pointless though, the proper CVT was much better.
>>> "a bit pointless"??? its retardation blows my freakin' mind!!! cvt is
>>> brilliant - i've driven it and loved it. but the masses, whether their
>>> expectations are misled by the sales droids or not, "want" the "feel" of
>>> distinct ratios. it's utterly illogical and negates the whole point.
>>
>> True, but it costs the price of a switch and probably 100 lines of
>> computer code, and might sell more cars.
>
> but it defeats the whole point of bothering with cvt in the first place!

It is retarded, and actually I am enough of a geek that even though I
would never use it just having it on the car would put me off buying
one.

> and it'll cause uneven wear on the cones.

I hadn't thought of that. Then you'd end up with it getting notched in
some of the 6 ratios (probably top, as the most used) when it was
supposed to be CVT. It would start working like a conventional
automatic.

[...]
> with vacuum servos. not a sophisticated system, but it worked just
> great. it had something like a 650cc 2-cylinder motor, but because it
> was always perfectly geared, it was like a rocket off the line and would
> cruise at a steady 80 no problems. great in snow too because it had two
> drive belts, effectively acting like a limited slip diff. had a switch
> on the dash that you had to press to get it to do engine braking. a
> strange beast, but like i said, it was a very useful system and utilized
> that puny little engine most effectively.

So did it maintain the revs always around the same value (3500 or so),
or did it let them go up and down?

The thing is you get best economy and torque at lower revs but best
power at higher revs. Hence all the throttle position sensing and stuff
on the BMW.

jim beam

01-04-1970, 12:31 AM

Ben C wrote:
> On 2008-01-16, jim beam <spamvortex@bad.example.net> wrote:
>> Ben C wrote:
>>> On 2008-01-15, jim beam <spamvortex@bad.example.net> wrote:
>>>> Ben C wrote:
> [...]
>>>>> manual mode where you get to choose between 6 "virtual ratios" with a
>>>>> sequential action on the gearlever.
>>>>>
>>>>> A BMW with CVT I drove once had that (it was the BMW "Mini"). It was a
>>>>> bit pointless though, the proper CVT was much better.
>>>> "a bit pointless"??? its retardation blows my freakin' mind!!! cvt is
>>>> brilliant - i've driven it and loved it. but the masses, whether their
>>>> expectations are misled by the sales droids or not, "want" the "feel" of
>>>> distinct ratios. it's utterly illogical and negates the whole point.
>>> True, but it costs the price of a switch and probably 100 lines of
>>> computer code, and might sell more cars.
>> but it defeats the whole point of bothering with cvt in the first place!
>
> It is retarded, and actually I am enough of a geek that even though I
> would never use it just having it on the car would put me off buying
> one.

my opinion exactly.

>
>> and it'll cause uneven wear on the cones.
>
> I hadn't thought of that. Then you'd end up with it getting notched in
> some of the 6 ratios (probably top, as the most used) when it was
> supposed to be CVT. It would start working like a conventional
> automatic.
>
> [...]
>> with vacuum servos. not a sophisticated system, but it worked just
>> great. it had something like a 650cc 2-cylinder motor, but because it
>> was always perfectly geared, it was like a rocket off the line and would
>> cruise at a steady 80 no problems. great in snow too because it had two
>> drive belts, effectively acting like a limited slip diff. had a switch
>> on the dash that you had to press to get it to do engine braking. a
>> strange beast, but like i said, it was a very useful system and utilized
>> that puny little engine most effectively.
>
> So did it maintain the revs always around the same value (3500 or so),
> or did it let them go up and down?

they'd go up and down, but cruising from say 40-70 were very narrowly
confined. accelerating from zero was fascinating because you'd surge
forward with constant highish revs, and the engine pitch would remain
absolutely constant as the car just got faster and faster.

>
> The thing is you get best economy and torque at lower revs but best
> power at higher revs. Hence all the throttle position sensing and stuff
> on the BMW.

tps is not confined to the control of this kind of transmission, it's
common to all electronic fuel injection systems. and once you're
electronic, everything else is mapped or calculated, so adding
transmission control is relatively straight forward. if you feel like a
science project, there's a diy open source fuel injection system out
there called megasquirt [megasquirt.info]. it would be interesting to
augment that for transmission control.

still just me

01-04-1970, 12:31 AM

On Wed, 16 Jan 2008 04:17:57 -0600, Ben C <spamspam@spam.eggs> wrote:

>The thing is you get best economy and torque at lower revs but best
>power at higher revs. Hence all the throttle position sensing and stuff
>on the BMW.

Torque is power. Or, more correctly, horsepower doesn't even exist
except via mathematical formula.

Ben C

01-04-1970, 12:32 AM

On 2008-01-16, still just me <wheeledBobNOSPAM@yahoo.com> wrote:
> On Wed, 16 Jan 2008 04:17:57 -0600, Ben C <spamspam@spam.eggs> wrote:
>
>>The thing is you get best economy and torque at lower revs but best
>>power at higher revs. Hence all the throttle position sensing and stuff
>>on the BMW.
>
> Torque is power. Or, more correctly, horsepower doesn't even exist
> except via mathematical formula.

What _are_ you talking about?

Michael Press

01-04-1970, 12:32 AM

In article <g25so3l0povhujvtivprgj5c3se4lgcql1@4ax.com>,
still just me <wheeledBobNOSPAM@yahoo.com> wrote:

> On Wed, 16 Jan 2008 04:17:57 -0600, Ben C <spamspam@spam.eggs> wrote:
>
> >The thing is you get best economy and torque at lower revs but best
> >power at higher revs. Hence all the throttle position sensing and stuff
> >on the BMW.
>
> Torque is power.

No, that is not the case.

mass
weight
momentum
speed
velocity
acceleration
torque
force
distance
angular momentum
energy
work
power
moment of inertia

These words have precise definitions.
Each is a quantity with dimensions.

> Or, more correctly, horsepower doesn't even exist
> except via mathematical formula.

Horsepower can be measured directly.

--
Michael Press

still just me

01-04-1970, 12:32 AM

On Wed, 16 Jan 2008 09:06:11 -0600, Ben C <spamspam@spam.eggs> wrote:

>>>The thing is you get best economy and torque at lower revs but best
>>>power at higher revs. Hence all the throttle position sensing and stuff
>>>on the BMW.
>>
>> Torque is power. Or, more correctly, horsepower doesn't even exist
>> except via mathematical formula.
>
>What _are_ you talking about?

Perhaps I should have emphasized "Torque *is* power". Horsepower is
*calculated* mathematically by measuring *torque* on a dyno.

Statements like "best economy and torque at lower revs but best power
at higher revs" infer that "torque" is different than "power"
(e.g. horsepower) and that torque has effect at lower rpms and
horsepower has effect at higher rpms - when in fact they are one in
the same.

jobst.brandt@stanfordalumni.org

01-04-1970, 12:34 AM

Bob who? writes:

>>>> The thing is you get best economy and torque at lower revs but
>>>> best power at higher revs. Hence all the throttle position
>>>> sensing and stuff on the BMW.

>>> Torque is power. Or, more correctly, horsepower doesn't even exist
>>> except via mathematical formula.

>> What _are_ you talking about?

> Perhaps I should have emphasized "Torque *is* power". Horsepower is
> *calculated* mathematically by measuring *torque* on a dyno.

That's an odd way to define power. Power is torque x RPM with the
right times constants of conversion. At constant torque, power
increases linearly with increased speed and at constant power, torque
decreases linearly with increased speed. The units for power are
usually Watts or HP.

However, there is generally more fluid friction at higher rotational
speeds so there is a slight non-linearity as speed changes although
not one that affects average users.

> Statements like "best economy and torque at lower revs but best
> power at higher revs" infer that "torque" is different than "power"
> (e.g. horsepower) and that torque has effect at lower RPM and
> horsepower has effect at higher RPM - when in fact they are one in
> the same.

I don't know what your are developing with that paragraph but torque
and power are not the same. RPM not rpms. It's an acronym for
Revolutions Per Minute.

That's marketing BS that tries to confuse the issue.

Jobst Brandt

Helmut Springer

01-04-1970, 12:34 AM

still just me <wheeledBobNOSPAM@yahoo.com> wrote:
> Perhaps I should have emphasized "Torque *is* power".

It isn't, simple.

Power (Watt=J/s=Nm/s) is Torque (Nm) times rotational frequency (1/s).

--
MfG/Best regards
helmut springer panta rhei

still just me

01-04-1970, 12:34 AM

On 17 Jan 2008 00:09:15 GMT, jobst.brandt@stanfordalumni.org wrote:

>> Statements like "best economy and torque at lower revs but best
>> power at higher revs" infer that "torque" is different than "power"
>> (e.g. horsepower) and that torque has effect at lower RPM and
>> horsepower has effect at higher RPM - when in fact they are one in
>> the same.
>
>I don't know what your are developing with that paragraph but torque
>and power are not the same. RPM not rpms. It's an acronym for
>Revolutions Per Minute.
>
>That's marketing BS that tries to confuse the issue.

But that's my point. Horsepower can only be calculated. It is the
application of torque-> spin, but it's also a calculated figure. Give
me the torque/RPM, and I'll give you the horsepower. Horsepower is, in
a sense, a useless figure - you could throw away HP numbers and just
cite torque @ RPM. But horsepower numbers are bigger, so manufacturers
like those.

Strictly speaking, HP is the more correct since we care about power,
not potential power, but an auto engine is always spinning and one or
the other is always calculable, so pick one and use it. My beef is
when people suggest that somehow auto engines change from using
something called "torque" at low speeds to something called "HP" at
high speeds.

jim beam

01-04-1970, 12:37 AM

Helmut Springer wrote:
> still just me <wheeledBobNOSPAM@yahoo.com> wrote:
>> Perhaps I should have emphasized "Torque *is* power".
>
> It isn't, simple.
>
> Power (Watt=J/s=Nm/s) is Torque (Nm) times rotational frequency (1/s).
>
>

praise the lord!

jobst.brandt@stanfordalumni.org

01-04-1970, 12:38 AM

Bob who? writes:

>>> Statements like "best economy and torque at lower revs but best
>>> power at higher revs" infer that "torque" is different than "power"
>>> (e.g. horsepower) and that torque has effect at lower RPM and
>>> horsepower has effect at higher RPM - when in fact they are one in
>>> the same.

>>I don't know what your are developing with that paragraph but torque
>>and power are not the same. RPM not rpms. It's an acronym for
>>Revolutions Per Minute.

>>That's marketing BS that tries to confuse the issue.

> But that's my point. Horsepower can only be calculated. It is the
> application of torque-> spin, but it's also a calculated figure.
> Give me the torque/RPM, and I'll give you the horsepower.
> Horsepower is, in a sense, a useless figure - you could throw away
> HP numbers and just cite torque @ RPM. But horsepower numbers are
> bigger, so manufacturers like those.

Not so. That's why cars have gears, to convert power to torque, the
wheels not turning at engine speed. At the engine power can be
measured directly as it is by every motor manufacturer. It is a
valuable parameter for the performance of a vehicle. Torque is less
practical because, for instance, most motor vehicles have the
necessary torque in low gear to spin the wheels. So that tells us
nothing about performance?

> Strictly speaking, HP is the more correct since we care about power,
> not potential power, but an auto engine is always spinning and one
> or the other is always calculable, so pick one and use it. My beef
> is when people suggest that somehow auto engines change from using
> something called "torque" at low speeds to something called "HP" at
> high speeds.

Power is the useful parameter, torque can be made with gears from
that. In contrast the torque curve together with peak power is
valuable information. It is often this curve to which people refer
when they speak of torque, although not aware of it. A desirable
engine has a broad range over which it produces its power, which means
it has a broad torque curve regardless of its peak.

A problem with high power engine tuning is that torque may fall off
more quickly to either side of the peak. This requires more gears to
keep the engine in its power range, power being torque times RPM. So
more gears may be an indicator that the engine has a narrow power band
rather than a desirable feature, other things being equal.

Jobst Brandt

Chalo

01-04-1970, 12:38 AM

still just me wrote:
>
> Horsepower is, in
> a sense, a useless figure - you could throw away HP numbers and just
> cite torque @ RPM. But horsepower numbers are bigger, so manufacturers
> like those.

That's like saying electrical watts is a useless figure since it can
be extrapolated from volts and amps. The fact remains that most of
the time, you want to know wattage and not amperage.

Transmission gearing renders absolute motor torque basically
irrelevant-- as a metric of performance, it's horsepower that
counts.

Chalo

Helmut Springer

01-04-1970, 12:38 AM

still just me <wheeledBobNOSPAM@yahoo.com> wrote:
> My beef is when people suggest that somehow auto engines change
> from using something called "torque" at low speeds to something
> called "HP" at high speeds.

They don't change, but when you compare a heavy truck and a sports
car both with 400HP you might get the idea...

--
MfG/Best regards
helmut springer panta rhei

still just me

01-04-1970, 12:38 AM

On 17 Jan 2008 17:57:45 GMT, jobst.brandt@stanfordalumni.org wrote:

>Not so. That's why cars have gears, to convert power to torque, the
>wheels not turning at engine speed.

Gears are irrelevant in a discussion of how much torque and/or power
an engine produces. The only possible interest is loss through the
drive train - that's not pertinent to this discussion of the
terminology.

>At the engine power can be
>measured directly as it is by every motor manufacturer. It is a
>valuable parameter for the performance of a vehicle.

That's only half correct. While manufacturers do measure at the engine
to get higher numbers (rather than the real numbers at the wheels),
they don't measure power. They measure torque, they calculate power.

>Torque is less
>practical because, for instance, most motor vehicles have the
>necessary torque in low gear to spin the wheels. So that tells us
>nothing about performance?

I'm not sure what your point it. When two measurements have a strict
mathematical relationship like torque and HP, only one is needed.

>Power is the useful parameter, torque can be made with gears from
>that. In contrast the torque curve together with peak power is
>valuable information. It is often this curve to which people refer
>when they speak of torque, although not aware of it.

Valid. But torque "through gears" is a completely different topic from
my issues with people distinguishing between torque and HP. We use the
torque/power of the engine through the gearbox to create torque/power
in another machine.

>A desirable
>engine has a broad range over which it produces its power, which means
>it has a broad torque curve regardless of its peak.

Yes, my secondary point. Torque is the more important measurement.
But, I'll take either one as long as someone doesn't suggest that one
is used at one end of the RPM range and one at the other.

>A problem with high power engine tuning is that torque may fall off
>more quickly to either side of the peak. This requires more gears to
>keep the engine in its power range, power being torque times RPM. So
>more gears may be an indicator that the engine has a narrow power band
>rather than a desirable feature, other things being equal.

Agreed on all points, but again, not germane to the discussion.

And the problem with marketing is that people don't know squat about
torque, or RPMs, they just look at a peak HP figure at whatever RPM
the manufacturer could peak it at and use the number - regardless of
the fact that it might be a spike, or sometimes even outside the
engines normal operating range (except when pushed hard). Many engines
peak too early, or too late, or have a narrow band, all of which slips
past the average buyer.

>
>Jobst Brandt

Tom Sherman

01-04-1970, 12:38 AM

jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> ...
> A problem with high power engine tuning is that torque may fall off
> more quickly to either side of the peak. This requires more gears to
> keep the engine in its power range, power being torque times RPM. So
> more gears may be an indicator that the engine has a narrow power band
> rather than a desirable feature, other things being equal.
>
That is why Otto cycle engines should have variable valve timing and lift.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

jobst.brandt@stanfordalumni.org

01-04-1970, 12:39 AM

Tom Sherman writes:

>> ... A problem with high power engine tuning is that torque may
>> fall off more quickly to either side of the peak. This requires
>> more gears to keep the engine in its power range, power being
>> torque times RPM. So more gears may be an indicator that the
>> engine has a narrow power band rather than a desirable feature,
>> other things being equal.

> That is why Otto cycle engines should have variable valve timing and
> lift.

That sounds good, but you cant get there from here. Highly tuned
engines get higher peak performance but the eds of the power band
can't be made to rise equally, so the torque curve has a narrower or
more arched form. Variable valve timing may get rid of overlap at the
end of the exhaust stroke and beginning of the intake stroke, but that
doesn't do much good for broadening the torque curve. There isn't
much power there to be gained.

The simple answer is to supercharge, but that has even more headaches.
Because the engine is compression limited, not being or wanting to be
a Diesel, supercharged engines must be lower compression from the
start. Their power band is broader but their fuel economy at lower
(most prevalent) engine speeds is poor.

Don't think there aren't great minds at work in the auto industry.
They go to great expense to solve these riddles. You are not going to
do it from the keyboard or bicycle saddle for that matter. I spent
interesting times around that work designing camshafts and other car
parts.

Jobst Brandt

jim beam

01-04-1970, 12:39 AM

jobst.brandt@stanfordalumni.org wrote:
> Tom Sherman writes:
>
>>> ... A problem with high power engine tuning is that torque may
>>> fall off more quickly to either side of the peak. This requires
>>> more gears to keep the engine in its power range, power being
>>> torque times RPM. So more gears may be an indicator that the
>>> engine has a narrow power band rather than a desirable feature,
>>> other things being equal.
>
>> That is why Otto cycle engines should have variable valve timing and
>> lift.
>
> That sounds good, but you cant get there from here. Highly tuned
> engines get higher peak performance but the eds of the power band
> can't be made to rise equally, so the torque curve has a narrower or
> more arched form. Variable valve timing may get rid of overlap at the
> end of the exhaust stroke and beginning of the intake stroke, but that
> doesn't do much good for broadening the torque curve. There isn't
> much power there to be gained.
>
> The simple answer is to supercharge, but that has even more headaches.
> Because the engine is compression limited, not being or wanting to be
> a Diesel, supercharged engines must be lower compression from the
> start. Their power band is broader but their fuel economy at lower
> (most prevalent) engine speeds is poor.
>
> Don't think there aren't great minds at work in the auto industry.

shame that's not true of some segments of the bike industry. wheel
books for example.

> They go to great expense to solve these riddles. You are not going to
> do it from the keyboard or bicycle saddle for that matter. I spent
> interesting times around that work designing camshafts and other car
> parts.

so for how long did you work in "automobile design engineering" jobst?
and in what capacity?

Tom Sherman

01-04-1970, 12:39 AM

jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> Tom Sherman writes:
>
>>> ... A problem with high power engine tuning is that torque may
>>> fall off more quickly to either side of the peak. This requires
>>> more gears to keep the engine in its power range, power being
>>> torque times RPM. So more gears may be an indicator that the
>>> engine has a narrow power band rather than a desirable feature,
>>> other things being equal.
>
>> That is why Otto cycle engines should have variable valve timing and
>> lift.
>
> That sounds good, but you cant get there from here. Highly tuned
> engines get higher peak performance but the eds of the power band
> can't be made to rise equally, so the torque curve has a narrower or
> more arched form. Variable valve timing may get rid of overlap at the
> end of the exhaust stroke and beginning of the intake stroke, but that
> doesn't do much good for broadening the torque curve. There isn't
> much power there to be gained....
>
Better tell that to Honda Motor Company, Limited!

Having driven Honda's with variable valve timing and lift for the last
14 years, I can verify that in real life the engines behave like a
normal engine tuned for midrange power, at less than 5000 RPM. This
includes excellent fuel economy for the size and weight of the car.
However, the difference is that instead of the high end power dropping
off, the engines pull strongly all the way to the fuel cutoff at 7000+ RPM.

The engines are also quite durable. My 1994 Si never used any measurable
amount of oil, and had excellent compression at 160,000+ miles, despite
being driven almost abusively hard on a regular basis. Nothing was ever
done to the engine for maintenance, beyond oil/filter changes, scheduled
valve lash adjustments and scheduled timing belt and spark plug
replacements.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

Michael Baldwin

01-04-1970, 12:39 AM

>I spent interesting times around that work designing camshafts and
>other car parts.
>Jobst Brandt

I've never understood the term "cam phase" and it's relationship to cam
design, would you elaborate please?

Best Regards - Mike Baldwin

still just me

01-04-1970, 12:39 AM

On 18 Jan 2008 01:59:18 GMT, jobst.brandt@stanfordalumni.org wrote:

>The simple answer is to supercharge, but that has even more headaches.
>Because the engine is compression limited, not being or wanting to be
>a Diesel, supercharged engines must be lower compression from the
>start. Their power band is broader but their fuel economy at lower
>(most prevalent) engine speeds is poor.
>

Not _that_ much lower. Compression is still at fairly normal levels in
a turbo or supercharged engine, it's just not at "performance engine"
levels. So, unless you have a large displacement engine, performance
before the blower kicks in is not outstanding. But as long as the
super or turbo charger is tuned to a reasonable band of performance,
the vehicle will still get better performance/mileage overall compared
to a similar performing NA engine. For those that want low as well has
high speed performance, dual turbos are the best solution.

Driving such a vehicle does typically require slightly different
techniques to maximize low speed performance but it's still adequate
and the overall balance and performance make it a winner.

>Don't think there aren't great minds at work in the auto industry.
>They go to great expense to solve these riddles. You are not going to
>do it from the keyboard or bicycle saddle for that matter. I spent
>interesting times around that work designing camshafts and other car
>parts.

But unfortunately they are often limited by factors other than what
they can design.

jobst.brandt@stanfordalumni.org

01-04-1970, 12:40 AM

Tom Sherman writes:

>>>> ... A problem with high power engine tuning is that torque may
>>>> fall off more quickly to either side of the peak. This requires
>>>> more gears to keep the engine in its power range, power being
>>>> torque times RPM. So more gears may be an indicator that the
>>>> engine has a narrow power band rather than a desirable feature,
>>>> other things being equal.

>>> That is why Otto cycle engines should have variable valve timing
>>> and lift.

>> That sounds good, but you cant get there from here. Highly tuned
>> engines get higher peak performance but the eds of the power band
>> can't be made to rise equally, so the torque curve has a narrower
>> or more arched form. Variable valve timing may get rid of overlap
>> at the end of the exhaust stroke and beginning of the intake
>> stroke, but that doesn't do much good for broadening the torque
>> curve. There isn't much power there to be gained...

> Better tell that to Honda Motor Company, Limited!

> Having driven Honda's with variable valve timing and lift for the
> last 14 years, I can verify that in real life the engines behave
> like a normal engine tuned for midrange power, at less than 5000
> RPM. This includes excellent fuel economy for the size and weight
> of the car. However, the difference is that instead of the high end
> power dropping off, the engines pull strongly all the way to the
> fuel cutoff at 7000+ RPM.

> The engines are also quite durable. My 1994 Si never used any
> measurable amount of oil, and had excellent compression at 160,000+
> miles, despite being driven almost abusively hard on a regular
> basis. Nothing was ever done to the engine for maintenance, beyond
> oil/filter changes, scheduled valve lash adjustments and scheduled
> timing belt and spark plug replacements.

I don't know to what car you are comparing the performance here, but
in the days of old, auto magazines used to publish power curves by
which one could compare two engines of the same displacement. For
instance, my 1992 station wagon corners and brakes better than the
sports car I drove a few years back. I believe your endorsement of
the car but it doesn't resolve the problem of what did what. With a
power curve of the engine next to one of a competitor would be best.

Jobst Brandt

Michael Press

01-04-1970, 12:40 AM

In article <fmp9oe$jfe$1@registered.motzarella.org>,
Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:

> jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> > Tom Sherman writes:
> >
> >>> ... A problem with high power engine tuning is that torque may
> >>> fall off more quickly to either side of the peak. This requires
> >>> more gears to keep the engine in its power range, power being
> >>> torque times RPM. So more gears may be an indicator that the
> >>> engine has a narrow power band rather than a desirable feature,
> >>> other things being equal.
> >
> >> That is why Otto cycle engines should have variable valve timing and
> >> lift.
> >
> > That sounds good, but you cant get there from here. Highly tuned
> > engines get higher peak performance but the eds of the power band
> > can't be made to rise equally, so the torque curve has a narrower or
> > more arched form. Variable valve timing may get rid of overlap at the
> > end of the exhaust stroke and beginning of the intake stroke, but that
> > doesn't do much good for broadening the torque curve. There isn't
> > much power there to be gained....
> >
> Better tell that to Honda Motor Company, Limited!
>
> Having driven Honda's with variable valve timing and lift for the last
> 14 years, I can verify that in real life the engines behave like a
> normal engine tuned for midrange power, at less than 5000 RPM. This
> includes excellent fuel economy for the size and weight of the car.
> However, the difference is that instead of the high end power dropping
> off, the engines pull strongly all the way to the fuel cutoff at 7000+ RPM.
>
> The engines are also quite durable. My 1994 Si never used any measurable
> amount of oil, and had excellent compression at 160,000+ miles, despite
> being driven almost abusively hard on a regular basis. Nothing was ever
> done to the engine for maintenance, beyond oil/filter changes, scheduled
> valve lash adjustments and scheduled timing belt and spark plug
> replacements.

What he says. Good solid pulling in the fuel efficient range,
and no fall-off at higher engine speed. Rather the opposite:
truly respectable acceleration all the way to the end. Put
it in third on the freeway and get going now! Sixty to eighty
need not be waiting for Godot even in a family sedan.

--
Michael Press

jim beam

01-04-1970, 12:40 AM

jobst.brandt@stanfordalumni.org wrote:
> Tom Sherman writes:
>
>>>>> ... A problem with high power engine tuning is that torque may
>>>>> fall off more quickly to either side of the peak. This requires
>>>>> more gears to keep the engine in its power range, power being
>>>>> torque times RPM. So more gears may be an indicator that the
>>>>> engine has a narrow power band rather than a desirable feature,
>>>>> other things being equal.
>
>>>> That is why Otto cycle engines should have variable valve timing
>>>> and lift.
>
>>> That sounds good, but you cant get there from here. Highly tuned
>>> engines get higher peak performance but the eds of the power band
>>> can't be made to rise equally, so the torque curve has a narrower
>>> or more arched form. Variable valve timing may get rid of overlap
>>> at the end of the exhaust stroke and beginning of the intake
>>> stroke, but that doesn't do much good for broadening the torque
>>> curve. There isn't much power there to be gained...
>
>> Better tell that to Honda Motor Company, Limited!
>
>> Having driven Honda's with variable valve timing and lift for the
>> last 14 years, I can verify that in real life the engines behave
>> like a normal engine tuned for midrange power, at less than 5000
>> RPM. This includes excellent fuel economy for the size and weight
>> of the car. However, the difference is that instead of the high end
>> power dropping off, the engines pull strongly all the way to the
>> fuel cutoff at 7000+ RPM.
>
>> The engines are also quite durable. My 1994 Si never used any
>> measurable amount of oil, and had excellent compression at 160,000+
>> miles, despite being driven almost abusively hard on a regular
>> basis. Nothing was ever done to the engine for maintenance, beyond
>> oil/filter changes, scheduled valve lash adjustments and scheduled
>> timing belt and spark plug replacements.
>
> I don't know to what car you are comparing the performance here, but
> in the days of old, auto magazines used to publish power curves by
> which one could compare two engines of the same displacement. For
> instance, my 1992 station wagon corners and brakes better than the
> sports car I drove a few years back. I believe your endorsement of
> the car but it doesn't resolve the problem of what did what. With a
> power curve of the engine next to one of a competitor would be best.
>

jeepers jobst. the honda design uses two [or more] sets of cam lobes,
with different profiles, and switches between them depending on the
engine's rpm range [and latterly, desired output]. in this case,
there's just one car, but two sets of cam profiles and therefore, a
significantly modified output graph. this technology was in the honda
civic in 1992.

when did your ability to detect that there was something that you didn't
know and therefore should look up before dismissing leave town? 1926?

Tom Sherman

01-04-1970, 12:40 AM

jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> Tom Sherman writes:
>
>>>>> ... A problem with high power engine tuning is that torque may
>>>>> fall off more quickly to either side of the peak. This requires
>>>>> more gears to keep the engine in its power range, power being
>>>>> torque times RPM. So more gears may be an indicator that the
>>>>> engine has a narrow power band rather than a desirable feature,
>>>>> other things being equal.
>
>>>> That is why Otto cycle engines should have variable valve timing
>>>> and lift.
>
>>> That sounds good, but you cant get there from here. Highly tuned
>>> engines get higher peak performance but the eds of the power band
>>> can't be made to rise equally, so the torque curve has a narrower
>>> or more arched form. Variable valve timing may get rid of overlap
>>> at the end of the exhaust stroke and beginning of the intake
>>> stroke, but that doesn't do much good for broadening the torque
>>> curve. There isn't much power there to be gained...
>
>> Better tell that to Honda Motor Company, Limited!
>
>> Having driven Honda's with variable valve timing and lift for the
>> last 14 years, I can verify that in real life the engines behave
>> like a normal engine tuned for midrange power, at less than 5000
>> RPM. This includes excellent fuel economy for the size and weight
>> of the car. However, the difference is that instead of the high end
>> power dropping off, the engines pull strongly all the way to the
>> fuel cutoff at 7000+ RPM.
>
>> The engines are also quite durable. My 1994 Si never used any
>> measurable amount of oil, and had excellent compression at 160,000+
>> miles, despite being driven almost abusively hard on a regular
>> basis. Nothing was ever done to the engine for maintenance, beyond
>> oil/filter changes, scheduled valve lash adjustments and scheduled
>> timing belt and spark plug replacements.
>
> I don't know to what car you are comparing the performance here, but
> in the days of old, auto magazines used to publish power curves by
> which one could compare two engines of the same displacement. For
> instance, my 1992 station wagon corners and brakes better than the
> sports car I drove a few years back. I believe your endorsement of
> the car but it doesn't resolve the problem of what did what. With a
> power curve of the engine next to one of a competitor would be best.
>
I have driven the VTEC (variable valve timing and valve lift electronic
control) Honda's back to back with standard engine versions, and at
lower RPM operation, the engines behave in a very similar manner.
However, the boost in high end power is very noticeable, such as passing
in 3rd gear at highway speeds.

Unfortunately, the costs of the engines (standard and VTEC) are hard to
compare, since getting the VTEC engine means also getting a higher
"trim" level.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

jobst.brandt@stanfordalumni.org

01-04-1970, 12:40 AM

Michael Baldwin <MLB5611@webtv.net> writes:

>> I spent interesting times around that work designing camshafts and
>> other car parts.

> I've never understood the term "cam phase" and it's relationship to
> cam design, would you elaborate please?

It's not part of my vocabulary either but I can imagine to what it
might refer. Each cam, intake and exhaust have a lift curve that
starts at zero, rises to a maximum lift and goes back to zero,
generally in a symmetric "mole hill" curve. Intake and exhaust cam
profiles differ in lift and duration and the two are "phased to
optimize their opening and closing, the two curves having some overlap
as the exhaust valve closes and the intake opens, the exiting gas
having inertia and can enhance "sucking" fresh fuel-air mixture into
the combustion chamber. For this we have both tuned exhaust and
intake channels so that the periodic compression wave motion in these
channels assist each other.

In the work I did, the cam centers were the values that were timed
(phased) to each other relative to piston TDC.

Jobst Brandt

jim beam

01-04-1970, 12:40 AM

Tom Sherman wrote:
> jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
>> Tom Sherman writes:
>>
>>>>>> ... A problem with high power engine tuning is that torque may
>>>>>> fall off more quickly to either side of the peak. This requires
>>>>>> more gears to keep the engine in its power range, power being
>>>>>> torque times RPM. So more gears may be an indicator that the
>>>>>> engine has a narrow power band rather than a desirable feature,
>>>>>> other things being equal.
>>
>>>>> That is why Otto cycle engines should have variable valve timing
>>>>> and lift.
>>
>>>> That sounds good, but you cant get there from here. Highly tuned
>>>> engines get higher peak performance but the eds of the power band
>>>> can't be made to rise equally, so the torque curve has a narrower
>>>> or more arched form. Variable valve timing may get rid of overlap
>>>> at the end of the exhaust stroke and beginning of the intake
>>>> stroke, but that doesn't do much good for broadening the torque
>>>> curve. There isn't much power there to be gained...
>>
>>> Better tell that to Honda Motor Company, Limited!
>>
>>> Having driven Honda's with variable valve timing and lift for the
>>> last 14 years, I can verify that in real life the engines behave
>>> like a normal engine tuned for midrange power, at less than 5000
>>> RPM. This includes excellent fuel economy for the size and weight
>>> of the car. However, the difference is that instead of the high end
>>> power dropping off, the engines pull strongly all the way to the
>>> fuel cutoff at 7000+ RPM.
>>
>>> The engines are also quite durable. My 1994 Si never used any
>>> measurable amount of oil, and had excellent compression at 160,000+
>>> miles, despite being driven almost abusively hard on a regular
>>> basis. Nothing was ever done to the engine for maintenance, beyond
>>> oil/filter changes, scheduled valve lash adjustments and scheduled
>>> timing belt and spark plug replacements.
>>
>> I don't know to what car you are comparing the performance here, but
>> in the days of old, auto magazines used to publish power curves by
>> which one could compare two engines of the same displacement. For
>> instance, my 1992 station wagon corners and brakes better than the
>> sports car I drove a few years back. I believe your endorsement of
>> the car but it doesn't resolve the problem of what did what. With a
>> power curve of the engine next to one of a competitor would be best.
>>
> I have driven the VTEC (variable valve timing and valve lift electronic
> control) Honda's back to back with standard engine versions, and at
> lower RPM operation, the engines behave in a very similar manner.
> However, the boost in high end power is very noticeable, such as passing
> in 3rd gear at highway speeds.
>
> Unfortunately, the costs of the engines (standard and VTEC) are hard to
> compare, since getting the VTEC engine means also getting a higher
> "trim" level.
>

i have direct comparison of cam profile effects. two hondas, identical
motors, one with the stock soh ["low rev"] cam, the other with a soh zc
["racing"] cam.

the stock cam is the better at low rpm's and best suited to normal
driving. by about 5krpm, it's ok, but it's starting to run out of puff.
with the zc cam otoh, below about 4.5krpm, the thing works ok, but
it's no great shakes and certainly has a hard time keeping up with the
stock cam motor. above about 5k however, it really lights up and leaves
the other motor standing. the difference is dramatic.

your later model motor, with the vtec head, marries these two profiles
on the same cam and switches between them as required - the benefits of
the low rev cam and the high rev cam. its a great [relatively low cost]
solution to an otherwise insoluble problem.

jim beam

01-04-1970, 12:40 AM

jobst.brandt@stanfordalumni.org wrote:
> Michael Baldwin <MLB5611@webtv.net> writes:
>
>>> I spent interesting times around that work designing camshafts and
>>> other car parts.
>
>> I've never understood the term "cam phase" and it's relationship to
>> cam design, would you elaborate please?
>
> It's not part of my vocabulary either but I can imagine to what it
> might refer. Each cam, intake and exhaust have a lift curve that
> starts at zero, rises to a maximum lift and goes back to zero,
> generally in a symmetric "mole hill" curve. Intake and exhaust cam
> profiles differ in lift and duration and the two are "phased to
> optimize their opening and closing, the two curves having some overlap
> as the exhaust valve closes and the intake opens, the exiting gas
> having inertia and can enhance "sucking" fresh fuel-air mixture into
> the combustion chamber. For this we have both tuned exhaust and
> intake channels so that the periodic compression wave motion in these
> channels assist each other.
>
> In the work I did, the cam centers were the values that were timed
> (phased) to each other relative to piston TDC.
>

er, i think this technology pre-dated you jobst. by some decades. what
exactly are you trying to say you brought to the table?

Michael Baldwin

01-04-1970, 12:40 AM

>In the work I did, the cam centers were the
>values that were timed (phased) to each other relative to
>piston TDC.
>Jobst Brandt

I'm assuming that these phased centers are advanced or retarded in
relationship to piston TDC timing , no?

Best Regards - Mike Baldwin

Tom Sherman

01-04-1970, 12:40 AM

"jim beam" wrote:
> Tom Sherman wrote:
>> jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
>>> Tom Sherman writes:
>>>
>>>>>>> ... A problem with high power engine tuning is that torque may
>>>>>>> fall off more quickly to either side of the peak. This requires
>>>>>>> more gears to keep the engine in its power range, power being
>>>>>>> torque times RPM. So more gears may be an indicator that the
>>>>>>> engine has a narrow power band rather than a desirable feature,
>>>>>>> other things being equal.
>>>
>>>>>> That is why Otto cycle engines should have variable valve timing
>>>>>> and lift.
>>>
>>>>> That sounds good, but you cant get there from here. Highly tuned
>>>>> engines get higher peak performance but the eds of the power band
>>>>> can't be made to rise equally, so the torque curve has a narrower
>>>>> or more arched form. Variable valve timing may get rid of overlap
>>>>> at the end of the exhaust stroke and beginning of the intake
>>>>> stroke, but that doesn't do much good for broadening the torque
>>>>> curve. There isn't much power there to be gained...
>>>
>>>> Better tell that to Honda Motor Company, Limited!
>>>
>>>> Having driven Honda's with variable valve timing and lift for the
>>>> last 14 years, I can verify that in real life the engines behave
>>>> like a normal engine tuned for midrange power, at less than 5000
>>>> RPM. This includes excellent fuel economy for the size and weight
>>>> of the car. However, the difference is that instead of the high end
>>>> power dropping off, the engines pull strongly all the way to the
>>>> fuel cutoff at 7000+ RPM.
>>>
>>>> The engines are also quite durable. My 1994 Si never used any
>>>> measurable amount of oil, and had excellent compression at 160,000+
>>>> miles, despite being driven almost abusively hard on a regular
>>>> basis. Nothing was ever done to the engine for maintenance, beyond
>>>> oil/filter changes, scheduled valve lash adjustments and scheduled
>>>> timing belt and spark plug replacements.
>>>
>>> I don't know to what car you are comparing the performance here, but
>>> in the days of old, auto magazines used to publish power curves by
>>> which one could compare two engines of the same displacement. For
>>> instance, my 1992 station wagon corners and brakes better than the
>>> sports car I drove a few years back. I believe your endorsement of
>>> the car but it doesn't resolve the problem of what did what. With a
>>> power curve of the engine next to one of a competitor would be best.
>>>
>> I have driven the VTEC (variable valve timing and valve lift
>> electronic control) Honda's back to back with standard engine
>> versions, and at lower RPM operation, the engines behave in a very
>> similar manner. However, the boost in high end power is very
>> noticeable, such as passing in 3rd gear at highway speeds.
>>
>> Unfortunately, the costs of the engines (standard and VTEC) are hard
>> to compare, since getting the VTEC engine means also getting a higher
>> "trim" level.
>>
>
> i have direct comparison of cam profile effects. two hondas, identical
> motors, one with the stock soh ["low rev"] cam, the other with a soh zc
> ["racing"] cam.
>
> the stock cam is the better at low rpm's and best suited to normal
> driving. by about 5krpm, it's ok, but it's starting to run out of puff.
> with the zc cam otoh, below about 4.5krpm, the thing works ok, but it's
> no great shakes and certainly has a hard time keeping up with the stock
> cam motor. above about 5k however, it really lights up and leaves the
> other motor standing. the difference is dramatic.
>
> your later model motor, with the vtec head, marries these two profiles
> on the same cam and switches between them as required - the benefits of
> the low rev cam and the high rev cam. its a great [relatively low cost]
> solution to an otherwise insoluble problem.
>
In the 1.6L VTEC engine used in the 1992-95 Si/EX, the change in cam
profiles at about 4800 RPM was quite noticeable as a "bump" in power,
while the 1.7L VTEC in the 2002-05 EX has a seamless transition - except
for the wider than normal power band, one would never realize the VTEC
was there.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

A Muzi

01-04-1970, 12:40 AM

-snip engaging OT cars-
jim beam wrote:
> i have direct comparison of cam profile effects. two hondas, identical
> motors, one with the stock soh ["low rev"] cam, the other with a soh zc
> ["racing"] cam.

soh cam?

Acronymfinder wasn't helpful, web search turns up references to a man
named Cam Soh...
What is it?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Clive George

01-04-1970, 12:41 AM

"Tom Sherman" <sunsetss0003@REMOVETHISyahoo.com> wrote in message
news:fmph66$d61$1@registered.motzarella.org...

> In the 1.6L VTEC engine used in the 1992-95 Si/EX, the change in cam
> profiles at about 4800 RPM was quite noticeable as a "bump" in power,
> while the 1.7L VTEC in the 2002-05 EX has a seamless transition - except
> for the wider than normal power band, one would never realize the VTEC was
> there.

I've heard that the VTEC in the normal models is set up to be like that -
but the ones in the fast ones (Type-R over here) still have a distinct
bump - possibly to give the buyer reassurance that what they've bought is
working.

(does the second cam on a type R working between 6000 and 8000 rpm sound
about right? Part of the reason honda's NA engines manage such good specific
output is their ability to rev high.)

cheers,
clive