DocMo

Hi all,

I have had the AWE Xpipe on my GTS for 5000 miles and I just love it. It's a great sounding exhaust with valves open and still very quiet with no drone when valves are closed.

I'm considering adding sport headers and 200 cell cats for 2 reasons :
1. Improve throttle response and torque below 4000 rpms. (I know I won't get +30 hp).
2. Get a more exotic high pitch sound when valves are open.

Drone and / or loss of power / torque are No go for me even if it's very light.

I don't track my car and I would like to avoid ECU tune to keep my guarantee safe for now.

I would really appreciate if you share your first hand experience with similar set-ups. (I've seen MagicRat Dyno results with Fabspeed headers and cats).

Thanks a million!

jimbo1111

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cajerseyboy

You don't have to worry about ECU tune if you use the Cobb accessport. You can remove maps when you take it to the dealer. So I've heard.

c_Gio

I don't think AWE makes... Which are you thinking of getting?

Jnosol

I have a GTS. I was wondering about should I do x-pipe first or headers first. So I reached out to a guy on IG with both on his GTS.

Instagram User, joey_gts, has AWE Switchback and Fabspeed Sport Headers. He's extremely happy with the result. This is his exact quote when I asked him about it.

"I have both. AWE Switchback and Fabspeed Sport Headers with 200-cell cats. Orignally had AWE only and the sound was great, very loud and muscular but very much an exhaust sound. With the addition of the headers it is slightly louder, but more of an engine note than the exhaust only. Very high pitched and loud." - joey_gts

FYI: Cobb or ECU tuning isn't required with Sport Headers. Also keep in mind that not all aftermarket cats are made equal, only buy catted headers that uses HJS catalytic converters (OEM quality). Fabspeed, Cargraphicts, and GMG Racing are the few brands that uses HJS cats.

Based on my research, Fabspeed makes short/mid headers. Cargraphicts/GMG make long headers. Long headers are great if you spend most of your time at the higher RPM bands (i.e. racing purpose), but short headers have better low-mid gains for improved street driving experience.

DocMo

As I am in Europe and heard great feedback about Kline products I am going with their sport headers and 200 Cell cats (HJS HD from Germany). Felix Kline has been fantastic so far.
I will also Dyno my car before and after to document the impact on power and torque curves.
@ Jnosol, many thanks for sharing. This is exactly what I thought. Hence I am getting short/mid headers as the most important for me is street drivability and torque below 4000 rpms.
From a sound perspective if I get a more "exotic", higher pitched scream and more mechanical sound that's the icing on the cake!

Jnosol

In the U.S., we don't hear too much about Kline. I didn't realized Kline makes sport headers for the 991 GTS. Please share the link and info.

I know Kline's exhaust has a very interesting sound, since the centers are made of Inconel.

Also, ensure the headers are designed specifically for the GTS. The GTS' OEM headers are very high flowing compared to the S, Fabspeed's first version of 991 headers weren't GTS specific so a loss in power was reported. Their latest version is GTS specific.

DocMo

The headers and Cats I am ordering are Stainless steel I couldn't justify the extra cost of Inconel.
There are many reviews of their exhaust on the forum with pics. I am not recommending them yet that's not the goal of my thread. I'd like to focus on users' experience and feedback, dynos with similar set-up.
Good point on Fabspeed's first version loosing power however in their second try they've significant power gains.

_Phan_

Here's a video of what it'll most likely sound like.

DocMo

Thanks for the Video, it should be close but this is with decated race headers. Too extreme for me + CEL issues

R_Rated

Remember that reduction in back pressure(Headers/Cats) is going to increase HP but likely DECREASE TQ - especially low end and result in worse responsiveness.

The Sound will be amazing! Unfortunately, IMHO it make have the opposite effect you are looking for in responsiveness.

DocMo

@ R_Rated, are you sure about torque and responsiveness loss in low rpms with short tube headers? Any data or personal experience?
Thanks.

R_Rated

Personal experience although not from Porsche. I don't know of any specific data points but it's pretty common IP in modding cars.

Back pressure is a large factor in TQ and when you lose too much back pressure you hurt the performance. Dial in the right amount[or lack of - back pressure] and you gain HP at the top end at the cost of low TQ at the bottom end - every car will have difference proportions but assume that any gains up top will cost you proportionately on the bottom with high flowing cats/headers.

Headers will impact power more so than exhaust on our cars.

That being said; and as the owner of one of the better aftermarket exhausts, I seriously doubt an exhaust makes any quantifiable difference in performance on our cars. I do love the sound of mine though!

Just like HP claims for exhaust on our cars... the low end TQ numbers; if there are any, are all marketing propaganda and hype. It WILL SOUND awesome though

DocMo

What about MagicRat Dyno results with Sport headers and cats?

R_Rated

"assuming baseline numbers are correct"...

We all justify these mods the way we want to. I'd bet a lot of money this car performs no differently. This is "a Dyno" but it is not a dyno of the same car, in the same conditions, on the same da,y on the same dyno, etc... with and without modifications.

I'm not saying don't do it. It is fun to mod and will sound terrific. All I'm petitioning is that if you're trying to get low end response that headers are not a viable path to the desired results.

I don't have header/performance Cats on my car and don't want them but I'll still drool over his sound and what he's done. Very cool Mod, just not for me and my wants nor will it contribute to low end response/Tq.