No HP gain by aftermarket exhausts?

["Bradley Peet" <btpeet@effervescent.com>]

Whatchya smokin' over there, Jason?  We don't have to THINK there is a HP
gain with aftermarket exhausts.  We KNOW that there is a HP gain when
upgrading from stock to something like a TT exhaust because it's been PROVEN
by repeated tests on the dyno.

NOTE: For the sake of this discussion, I am talking about upgrading the
STOCK exhaust on a STOCK 16V Scirocco.

It's true that you probably will NOT notice the additional 5 HP of power
produced at 5500 RPM (or so), so clearly the performance effect of an
aftermarket exhaust is by no means dramatic.  HP gains from a new exhaust
system would be far more significant on a motor with cams, P&P, etc.

Effects of aftermarket exhausts upgrades (over stock) can be summarized as
follows:

1. Marginal gain in HP (on stock motors)
2. Increase in longevity over stock muffler (if you get stainless)
3. Dramatic increase in NOISE (esp if cat is removed)

The real point to this whole discussion is that aftermarket exhausts give
you marginal power increases in exchange for dramatic increases in the
volume of exhaust noise.

That said, I'd agree that 2.25" tubing is perfectly adequate for 1.8 and 2
liter normally aspirated engines.  I'd also agree that the sound of the
stock exhaust is far more pleasant than many aftermarket systems because it
allows you to actually hear the ENGINE, not just the overwhelming drone of a
non-cat, straight-through system.

So choose your exhaust system wisely.  If you want a modest power increases
without an increase in noise, get a high-flow baffled muffler like the
Dynomax "Super Turbo" muffler.  That is the best bang for your buck (and
your ears).  This muffler is cheap, quiet, weighs far less than the stock
"boat anchor", and will allow the motor to breath better.  (One caveat: that
muffler won't last more than a couple years, so buy two.)

If you can tolerate a little more noise, get a straight-through muffler like
the Ultra Flo or a Borla.  As long as you keep the cat, the noise level
should still be reasonable when not at full throttle.

That's my 10 cents worth.

-Bradley
Alpine White 1988 Scirocco 16V
Cosmos Blue  1981 Scirocco S
R.I.P: '86 Scirocco 16V 2.0 "T"
http://dns.effervescent.com/vw/

> ------------------------------
> Date: Thu, 20 Apr 2000 13:58:55 -0400
> From: 16v Jason <jason@scirocco.org>
> Subject: Re: dynoed a 2008cc motor
>
> >--- StephyGee <stephygee@prodigy.net> wrote:
> > Okay, this is my confession, as I'm a closet
> > stock exhaust lover.
>
> LOL is right. :)  Me too!
>
> And I agree with Daun-- I don't think there's a tenth of a HP
> to be gained
> by aftermarket exhausts.  2.25 inch diameter exhaust tubing
> is *more* than
> sufficient for a 1.8 liter engine-- and certainly sufficient for a
> 2.0.  For _seriously_ tuned 2.0 (and above) liter engines, a
> small amount
> of power might be gained in the very top-end, but without the
> backpressure,
> probably at a sacrifice to low-end torque.
>
> My $0.02.
>
> (and my car has a stock exhaust. :)



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