Spec exhaust:: = to or > than

#1

Equal to my existing exhaust or (hopefully) greater than—that is the result that I had hoped for when I changed to the spec exhaust.

But, that is not what showed up on the dyno. Here is the story.

The spec exhaust was first: 157hp 156tq, three run average, the numbers were consistant…

This compared wonderfully to my 157/157 test of the same car in May 2006. I started to load-up and go home, figuring that the engine was two years older and probably a little down on power. And, after the good reports about the exhaust,I concluded that the new set-up made some “lost” power.

But, I had told others that I would do a back-to-back test. So I jacked up the car and proceeded to get hot with it.

Much to my surprise (and disappointment, I really wanted to be down on power so that no one would care if you ran a “slower” exhaust), the Muffler Mike two pipe set-up checked in at 163hp,159tq.

I’m at a loss to explain my bigger numbers versus the bigger spec system numbers that others have found.

Whether or not the audience agreed with the implementation of the exhaust rule, it does prove the point that a spec system was/is a wise idea.

I had previously concluded that changing the exhaust would not make for a dimes worth of difference. This was based on the same two pipes tested open and with the glasspacks turned in opposite directions. I was wrong.

Just my 2 cents worth of data.

Regards, Robert Patton

#2

And some anecdotal data. At Road Atlanta, I had my custom twin glass pack set-up. JP had the new Spec exhaust. He has a refreshed motor, I don’t. Coming out of T7 he had a better run and a little speed on me as he pulled away from me. I nailed it, he nailed it. I wasn’t drafting, but I got side-by-side down the back straight, and by the braking point I had pulled him by 3/4 of a car length, from behind!

Also at VIR during practice when Carter was driving 6/10 and I was driving 9.5/10, I was able to stay absolutely on his bumper out of Oak Tree all the way down the back straight. Again, he had the spec exhaust, I don’t. He has a refreshed engine, I don’t.

But as Robert said, this is really an argument in support of the spec exhaust. Then we’ll all be equal, even if we’re equally slower.

Sasha

#3

Ex36 wrote:

[quote]And some anecdotal data. At Road Atlanta, I had my custom twin glass pack set-up. JP had the new Spec exhaust. He has a refreshed motor, I don’t. Coming out of T7 he had a better run and a little speed on me as he pulled away from me. I nailed it, he nailed it. I wasn’t drafting, but I got side-by-side down the back straight, and by the braking point I had pulled him by 3/4 of a car length, from behind!

[/quote]

Sasha, at time this is what my exhaust looked like. I also had a huge leak at the manifold to downpipe junction.

#4

155MPH wrote:

[quote]Ex36 wrote:

[quote]And some anecdotal data. At Road Atlanta, I had my custom twin glass pack set-up. JP had the new Spec exhaust. He has a refreshed motor, I don’t. Coming out of T7 he had a better run and a little speed on me as he pulled away from me. I nailed it, he nailed it. I wasn’t drafting, but I got side-by-side down the back straight, and by the braking point I had pulled him by 3/4 of a car length, from behind!

[/quote]

Sasha, at time this is what my exhaust looked like. I also had a huge leak at the manifold to downpipe junction. [/quote]

You should have let Sasha cling to his delusions of being fast and powerful.

#5

I have the same 2-pipe Muffler Mike system as Robert, and sometime in the next couple weeks I plan to do the same back-to-back at the Balanced dyno for another data point. It’s really going to stink if I find that I’m going backwards even more with the new spec system, but if that’s the case then it does reinforce the need for a spec system.

If I’m going to have a shot at the 6th place trophy anytime soon, we might have to vote a few guys over into GTS3 to clear some room!

#6

As did I. Looking at the SpecExhaust© design, it seems logical that it would make more power. It’s basically a straight shot from the collector back whereas our twin pipe setup wraps around the rear subframe, no mandrel bends, etc. I’d love to hear what your dyno data tells you!