Dennis

Hi all, I installed the headers and hi flow cats yesterday. Did the job at my performance shop with the owner. I am not that familiar with the 911's that much, been doing 94t/T/968's for a long time. Job was relatively easy, about 3 hours to do.

I already had the Gemballa SS exhaust so I decided to stay uniform and installed their headers and cats as well. I am not sure about the source of the cats though. They were definitely not stock items from the U.S. and they were SS. I did notice that they had a factory Porsche part # on them so I am kinda curious about that. The number was very faint in the SS though.

Everything fit perfect and there were no problems with the install. I only got to drive the car a short distance and the traffic was fairly heavy when I did. I noticed the car was noticibly louder but not at all "loud" with the windows up, about 15% louder than with just the mufflers.

There is a marked increase in power in first and second gear, the car really responds well with lots of pull. It feels like there is a more uniform/linear delivery of power with this exhaust system. Before, in third gear at 3500rpms, the car would "lunge" forward if you just nailed the throttle, now, the power comes on smoother but the motor seems to build more power as the revs pass 4500 or so.... On the highway, the car doesnt feel much faster but it surely appears to be picking up speed at a much quicker rate, especially one it got over 110mph.

I know almost all modifiers are claiming the headers alone produce somewhere in the 15hp range and the cats another 3-6hp. I talked to a guy who did dyno a 996 with the exact same exhaust and he claimed(not a salesman)a 17 HP gain. Not sure if it quite feels like that though, need to drive it more.

I would be interested in seeing any dyno information that anyone has from similarly modified cars.

Huzurdd

Any pictures of the exhaust system ie; cats-headers???

roschpe

Sounds like you have the cats from porsche Motorsports..mine was the same way, very faint part#...mine are from the GT3...
i am also installing the Porsche Motorsports headers, and the light weight flywheel from Porsche..it is a Sachs unit it weighs 8lbs..the stock unit weight 28lbs.

I have not yet installed the flywheel yet but when i do, i also have to remapp the comp b/c of the lighter flywheel...

The flywheel should make a HUGE difference in rev build up..
i will let you know when i have it complete

Dennis

Hello, thanks for the input on the Cats. I have the parts CD which includes the GT-3 and I looked at that to see if they were the ones I got. The part numbers are different from stock but the location of the O2 sensors appear the same as stock units in the pictures on the CD. The pictures have always appeared accurate, I assumed they were not the Gt-3 units because the Cats I got have the sensors in different locations, one goes right into the Cat itself. Are those the ones you have as well?

Thanks Dennis

PS: no pictures yet