Just thought I would post this old exhaust comparison, for research purposes of todays exhausts. There are so many good exhausts, this at least gives some data for comparison purposes. The test was done by Imagine auto and I had basically retrieved the parts I was interested in. you can find the complete test online if you google. The only two on this list still around are the stock and the EP.



Exhaust type.........Db idle.........Db 3k rpm.......Db WOT .......Weight........Backpressure.........Max HP..........Max Torque
996TT Stock.........81/84...........93/96.............97/101.........54 lbs..........6.3 psi.................458 bhp...........502
EP.......................91/69...........103/86...........109/91..........54...............2.5.................. ....467...............538
Fabspeed Gn1.......94/88...........101/102..........110/104........30lbs...........2.25................... ..499................552
Fbspd Cat/pipe......88/85...........104/108..........114/105 .......11..............1.75.....................49 8................561
RUF exhaust..........92/80...........95/88..............100/92........53................3..................... ...462................498

the db is outside/inside..



HP for all exhausts
Exhaust...........2500.........3000........3500........4000........4500........5000........5500........6000........6500........7000........Average

Factory...............125..........182...........247..........338..........429 ..........448..........452..........440..........437..........419..........346.0
Europipe..............145.......... 213..........305..........409...........429..........455..........452..........464..........440..........439..........351.0
Fabspeed Gen1......128..........190.......... 271...........384..........447...........461..........463..........469..........452..........442..........376.9
Fabspeed pipe.......127..........189...........274..........385..........466...........493..........487..........490..........462..........402..........400.0
RUF...................136..........200...........274..........363..........404...........415..........425..........427..........438..........419..........361.0


Torque for all exhausts
Exhaust .........2500........3000........3500........4000........4500........5000.........5500........6000........6500........7000........Average

Factory ............263..........319...........371..........444..........501..........471..........431..........385 ..........354..........313........388.5
Europipe ...........305..........372..........458...........538..........500..........478..........432..........407..........356 ..........328 ........ 413.0
Fabspeed gn1.....268..........332...........407..........504..........521..........484..........442..........411..........365.......... 334 ........418.3
Fabspeed pipe....271..........330...........411..........505..........544..........518..........465..........429..........373 ..........302 ........433.8
RUF................284..........350...........411..........476..........472..........436..........406..........374 ..........354..........317 ........400.9


*edited to add correction per PM concerning EP results. Torque at 4000 rpm is 538 instead of the quoted 438

this also makes a huge difference in performance. The EP actually produced the highest torque. Very impressive.

 

Very interesting data. Is there really that much variation in HP and torque? Seems hard to believe. Also, can anyone estimate based on a comparison with these figures what the db's would be on the TJW mod?

 

Very interesting post, thanks.

It seems that CAT+pipes setup should give the best performance all over the rev range..

I read many times about torque loss with straight pipes..

Do you know if those number were measured after an ECU flash or with the stock program?

How is it?

 

here is more info about the car:

• A 2001 Porsche 996TT with 20,000miles, stage 4 ECU upgrade, and K24 turbos was used.
• A minimum of 50 miles was put on the car with each muffler to account for ECU calibration
• Dynojet 248 Dynamometer
• DB tests were taken 12 ft from rear of the car by a Radio Shack Digital db Reader part
number 33-2055
• Backpressure tested 3” post turbo and 3” pre cat
• 3k constant load pulls were done on the dyno, under part throttle load.
• SAE HP correction was done based on weather station information. The correction factor for
all runs was 1.06-1.07DIN.
• Intake temperatures were held to within 10 degrees F

 

Isn't this Stephen Kaspar's data?

 

yes, I stated Imagine Auto above as it was his shop. Not sure who was there to witness it. I found this doing some searching and stored it for me, but figured others might be interested for comparison to other newer exhausts. Especially the inside noise on each.

The EP is quite impressive for interior noise and it seems to me is the best compromise for performance and noise level....probably nothing that a lot of old timers in here don't already know

 

the only surprise here is how poorly the Ruf exhaust performed. It is barely above stock it seems that it actually lost power between 4500--6500 rpm

 

Oops...missed that.

I have the dyno sheets if anyone is interested...PDF format.

ImagineExhaust.pdf

 

interesting data, the dynos look interesting as well.

was anyone aside from Stephen, there to confirm this data? excellent and very extensive test for sure

 

FWIW

3db increase in sound = x1.23 increase in volume
6db increase in sound = x1.52 increase in volume
10db increase in sound = x2 increase in volume (double)
20db increase in sound = x4 increase in volume (quadruple)

 

updated via info provided in PM. EP has much more torque and the reading was a typo. The corrected number looks much better. The EP is the highest torque of all tested along with the quietest sound. Impressive.

 

Good post Dennis, someone needs to add a kreissieg for comparison, of course finding a like control vehicle will be very difficult.

 

Dennis is this the old data that was posted years ago, or is this newer data?

Mike

 

Mike, it's old data from somewhere else. it was not posted here. I did a search before posting it. But you probably have seen it before. Of course the results are always suspect. I have a hard time believing that an aftermarket Ruf exhaust is worse than stock.

 

If IA did the comparison no need to verify. He is a straight shooter and fellow PCA technical advison with integrity. I am just sad not to see my JIC TI in the mix.