APEX GT3

Anyone running performance headers with sport cats with the stock PSE exhaust?

If so, what headers and cats did you go with and how’s the sound without an after market rear section exhaust?

Tupper

Just curious, why would you do headers and cats but not change the exhaust?

APEX GT3

The Porsche sport exhaust system is pretty well designed and I’m not gonna get much more power from amd aftermarket option. And I don’t want to increase the drone at all. I just don’t think it’s really necessary unless you’re going for ultimate sound - I would do a straight path X pipe performance exhaust if I wanted that option. I don’t want it to be extremely loud.

Tupper

^ I’m not expert, but to me it seems that if there is a “choke” on gas flow at any point in the system, even further downstream, then widening the system upstream would still not achieve the intended effect of increasing power.

In other words, you have headers but then you’ve got the PSE with the valves and mufflers slowing down the path of gas, which would affect flow through the entire system anyhow.

Anyone want to weigh in?

centaur

I could be be wrong in regards to the 992 but late model stock exhausts are pretty damn good performance wise but may not render the quality or decibel level of sound that we as individuals prefer. In other words an aftermarket exhasut is usually about sound and has little to no increase in performance. Once again I am not certain if this holds true with the 992 series cars.

APEX GT3

That’s my feeling on it. The 992 has a much better sounding PSE on it than the 991.2.

With adding headers and sport cats on the 992, I don’t think another 5k is worth it for the minimal performance of an aftermarket exhaust.
As for for the sound:
- valved is expensive and won’t change the sound that much
- no valve and free flow is very loud at cold start and starts to pull away from the refined 911 sound IMO

The heavier air flow from the performance headers will push into the turbo. The sport cats will be sending more pressure into the PSE system which will generate more volume.

The 700 cel stock cats are very restrictive and I (believe) that the PSE is not the restrictive part of the exhaust system. (Coming from reviews and advice I’ve gathered from vendors who sell aftermarket exhausts).

but who knows. LoL

Kurac

I don’t believe I’ve seen an aftermarket cat back that advertises adding any extra horsepower. So with that being said, I’d keep the stock PSE myself.

Tupper

^ Well, I’m doing the nonvalved exhaust mostly for sound and volume. I ran PSE with sports cats for a year, and I told myself it was enough but I was bulls**tting.

It just isn’t loud enough. Porsche knows their audience and they are a polite and…mature….one, hence the PSE.

Well, I just wasn’t satisfied. It’s not loud enough and it lacks oomph. So that’s why I’m doing it.

Now, I don’t entirely agree that a higher flowing exhaust won’t add power. Soul’s nonvalved exhaust increases diameter by 1/4 inch from cats to tip. No other aftermarket products have that diameter. Furthermore, once again you are getting rid of the valves entirely. If that alone isn’t enough to increase power, then couple it with a tune and now you’re in business. Is it a huge gain? Probably not, but I would wager you’d register a difference on a dyno

centaur

Your gains with an aftermarket cat back exhaust will be minimal if any. You can bank on that statement in the overwhelming number of applications as OEM exhausts do a great job performance wise. This is a very well known fact in this arena. Gains on the post combustion side come from headers and less restrictive catalytics. Cat back replacement exhausts are about sound.

Tupper

Oh, I agree that cats and headers increase hp, but would it be that dramatic either?

Also, even a catback exhaust can increase hp by small amounts.

Go onto YouTube and watch Kies Motorsports video where they compared dyno results for the BMW M340i before and after adding an AWE catback exhaust. HP gains of about 12-15 and torque gains about about 10 were what they discovered. That is not a lot, but it’s not insignificant

Tupper

There is someone here on Rennlist who has headers AND the Soul nonvalved exhaust. I think they have high flow cats like I’m doing. I forgot who it is, but that thing must be insanely loud!

Tupper

Here it is:

centaur

Exactly.

centaur

Yeah, like 2.5 % which you will never feel. Cat back is for sound NOT power.

Tupper

^ Well, I’ll still take it. But now you guys have got me wanting to get headers