dk996tt

I just removed my stock exhaust system off the 997 Turbo. I had 100 cell metallic substrate cats installed, about a 3" long turbo muffler (tried to quiet it down, but not too successful) and then tailpipe out the rear bumper. I felt a dramatic difference in power, probably in the tune of 40+ lb ft. of torque. Its pretty damn loud, but will do for now until i get a performance exhaust system for it. I was shocked at the improvement in throttle response and power. The first time I stepped into it in first gear, i bounced the tach off the rev limiter. This thing really spools fast, especially in first and second gears.

cooperlee

nice..it this a custom system you had made up with the 100 cats and mufflers or muffler bypass?

PorscheDoc

How did you come up with the 40ft/lb gain? Did you dyno it?

dk996tt

this is a custom made system with 100 cell cats. the muffler section is only about 3 to 4 inches long and then goes straight out the tips.

dk996tt

actually, the 40 ft/lb gain is from my butt dyno. i have dynoed many cars in the past and i must say that my butt dyno is pretty darn accurate. In fact, the first few times i drove the car with the new exhaust, i kept bouncing the tach off of the rev limiter in first gear. Not only does it pull much harder in first gear, but through all the gears. There is a noticeable difference. However, just to confirm my butt dyno, i am having my car dynoed in November when my real custom exhaust arrives.

slownrusty

PorschePhD

I have been running dynos on new systems and the most I have seen is 22 ft lbs which is pretty darn good in AWD. No offensive meant here but the Butt dyno is not really an accurate tool. I like my butt but the Mustang 500SE works a little better

allegretto

One must divide by at least 2, and sometimes 4 or greater to convert Butt to Mustang

dk996tt

i should have added "Dynojet" butt dyno, not mustang

allegretto

Is that what you call it?

PorschePhD

I hope it was not a Dynojet...Do not run a Porsche AWD on a uncoupled AWD dyno. Dynojet uses two different dynos to create 4 rollers. They do not operate at the same speed and will destroy the front diff.

dk996tt

i was just referring to the hp gain. we all know that dynojet hp numbers are substantially higher than mustang numbers. so a 40 hp gain on a dynojet would be equivalent to a 25 hp gain on a mustang dyno.

PorschePhD

Oh gottcha! Sorry. I am a little slow sometimes.

gota911

If your butt has a crack in it, then it is broken, so the "butt dyno" results may be flawed.

dk996tt

its got a crack in it, but it works pretty good!