Re: Exhaust???

[anderson@msai.mea.com (David Anderson)]

On Apr 15,  1:39pm, Donahue C. Herrero wrote:
> Subject: Exhaust???
> In the May issue of European Car there is an article on the Schmidt Racing
Team Corrado and GLX.
> 	It says:
> 		"...everything else (exhaust) was replaced with 1 3/4-inch
mandrel bent pipe...2 inch pipe was tried, but hurt low-end
		torque."
>
> these cars are racing in the showroom stock category.
> does this mean that we are going in the wrong direction by installing larger
diameter exhausts?
> anybody know the answer to this one?

I don't.  But I'm gonna guess.  (I have this issue at home, but I'm at work
now, so I can't look at it.)  I think when they replaced the exhaust, they're
talking about the WHOLE exhaust - getting rid of the cat, mufflers, etc., and
just using a straight pipe.  Is that right?

If that's the case, that would eliminate a large percentage (almost all?) of
the exhaust back pressure.  Eliminating the back pressure, for whatever reason,
helps high-end horsepower, but hurts low-end torque.  Therefore, to keep some
of the low-end torque, they wanted to retain some of the back pressure, and
thus they used a smaller pipe.

Most of us, when we replace our exhaust, keep our stock headers and cat, and
only go with a larger pipe from cat back.  Much of the exhaust back pressure
comes from these two components (headers and cat).  Thus, we've only slightly
eliminated some back pressure, helping high-end horsepower, while the low-end
losses can hardly be felt.

Anybody, feel free to refute/trash/totally shoot down my argument.  Like I said
- - I'm only guessing.  (Although, I think it's an educated guess.)

David
anderson@msai.mea.com