Old Library

I just got my Techtonic's 2.5 exhaust (2nd one in 2 years).  I'm once again
impressed with the build quality of this unit...

For those who doesn't know, Techtonics basically weld together the pipes
and terminate it to a Borla final muffler.  It has 2 resonators for noise
control.  With the option of stainless steel.

The bending of the pipes are just fine, as they are mandrel bent.  The
welds are definately done by HAND.  The welds are continous, but you can
see points that are a little heavier that others.  The resonators used are
straight through.  The design of this resonator (off the shelf item) relies
on using many little "tabs" (a little bigger then your thumb nail) placed
90o in relations to the pipe, in the perimeter to "collect" the air/sound
waves outwards to expanded resonator chamber.  It's not like the Borla
resonators ($$$) which the inside diameter remains constant, with a
straight flow and the air/sound waves are passed along inside a collender
style hole passage.

When you put the Borla final muffler next to the piping...  The difference
is quite dramatic.  In my pevious 2.5 system, the SS pipes brown/black out
quite quickly.  This is a sign of a grade of SS with less nickel content
(cheaper in another words)?  The piping around the welds are brown/black,
meaning...

This systems has proven to work quite well.  I wish they would put a little
more pride in the build quality and use a little higher quality parts.
>From a consumer point of view, $500 bucks is a lot of dough. We want it to
work AND look pretty for that price.

Jim
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There has been considerable debate concerning the gains with a cat-back
exhaust system.  I've always thought that the stock exhaust was pretty good
up to around 6000, but would choke the car above that, and that an
aftermarket exhaust would show the greatest gain up high in the rpm band..
Well, I was wrong!

Yesterday, I took my car to AWE and had the latest Techtonics Tuning
stainless steel exhaust system installed.  This system consists of two
resonators, a Borla muffler, and heavy-gauge 2-1/2" piping.  Fit and finish
is excellent.   My car has Schrick 268 cams, a Schrick VGi manifold, Garrett
11c chip, and the standard airbox mods (cone and snow-screen removed).

My car was dyno'd immediately before and after the exhaust installation.  The
results with the exhaust:

* +9 hp at the wheels at 6000 rpm.
* +13 ft-lbs of torque at the wheels at 3500 rpm!

This is obviously quite a bit more than the "5-6 hp" that is so often bandied
about when people talk about exhaust systems.  Now I cannot say if the
results with a "stock" engine (without the cams and manifold) would be
similar, but on my car, I'd say the gain is "signfigant"..:-)

With a 1.15 wheel-to-crank correction factor:

Stock Exhaust         TT Exhaust            Difference
191.6 hp @ 6000       201.8 hp @ 6000       +10.2 hp
184.6 ft-lb @ 3500    199.3 ft-lb @ 3500    +14.7 ft-lb

Some pictures of the exhaust and the dyno plots:
http://wso.net/ross/Uwe/VR6/tuning/tt-exhaust.html

- -Uwe-

PS:  It sounds GREAT outside the car.   But I haven't had it long enough to
make real comments regarding the liveability of the noise level inside the
car (a factor to which I'm rather sensitive).  Give me a few weeks! :-)