Doug H

The automobile magazine article mentioned tighter packed cats than those on the 996 for increased emissions. Does that equate to a more restrictive exhaist. If so, then it would seem pretty easy to squeeze a few more ponies and some more torque out of the 997 with an exhuast change.

sjsharks

Has anyone had any experience with the optional sports exhaust system?

Moogle

FYI the sports exhaust will be an option only on the Carrera S

Viken

Option XLF - Sport exhaust system includes sport pipes - Is available on both Carrera and Carrera S.

Viken

Assuming that is true, you won't gain anything by replacing cats with more free flowing ones. Without the backpressure designed into the stock exhaust, the car will lose a considerable amount of bottom end torque and gain a handful of ponies up near the engine's redline. A complete waste of effort and money. Besides, you need to come up with a way to fool that ECU after removing effective means of cutting back some emissions.

Doug H

I hear you, but would the same not hold true for other Porsche models. I have been experimenting around alot with the 964 engine and the cat bypass made more lower end torque and increased the overall area under the torque and hp curve, but the hp curve did drop off sooner (maybe 3 or 4 hunder RPMs) than the stock curve which seemed to be from a loss of back pressure. The drop off was 255 rwhp and still much higher than stock. We had felt like we could possible get 270 rwhp though if the curve had continued upward at 5,500 RPM Obviously I have alot of other mods, but the removal of the cat definitely freed up a whole lot of torque in the lower end as that was one of the last mods.

The TTs also benefit from freer flowing cats. Not sure about NA 996s though.

You may be right. I just thought maybe this might be a window of opportunity to take the 3.8 to even greater heights as far as horsepower if what the article reported about the cats was true. Maybe this will be an area where tuners can make some advancement on the 3.8 if Porsche is really building in greater restrictions based upon emissions concerns.

It would seem that there could be a lot of potential in a 3.8 and perhaps Porsche has held it back a little initially as they seem do hp increases in incriments over a model range.

Just food for thought and not trying to start an argument. The S would be awesome though if the 3.8 could be taken up to 380 or 400 hp through a remapped ECU and free flow exhaust.

Viken

Yes, turbocharged engines don't need nearly as much backpressure as normally aspirated engines.

sjsharks

But what exactly does the optional exhaust do?

Is it just a sound thing with no additional HP?

Viken

Yes.

petert

Correct me if I'm wrong, but I think the aftermarket exhausts for N/A cars use the stock cats anyway (probably for the reasons Viken mentions).

Viken

You are correct. Cats are left intact. Both, for that reason, and the fact that it is against the law to remove them.