2016GTS

I'm not big into modifying an already great car but I have been looking for some upgrades that will produce useful and dyno proven hp or torque increases. So does anybody know if there are muffler by pass systems out there with dyno test results? Or x pipe systems?

Aside from a cobb map anything else out there?

c_Gio

By-pass more of a turbo thing as I recall from searching. Several great x-pipe or exhaust options from a few grand to triple that.

Before/after dynos from real users are few and far between it seems.

You mentioned Cobb. The other I see is giac by way of awe. About same price.

Larry Cable

FVD.US

Cristophosphorus

Most exhaust manufacturers will put out a claim of ~5-25hp depending on the location in the powerband. I wouldn't pick up an exhaust just to gain power. But, theoretically, I've read that a straight-through x-pipe design will yield a bit more power compared to the stock PSE mid-muffler.

True or not, I'm not sure. But there are a ton of companies you can check out (FabSpeed, AWE, Cargraphic, FVD, etc.)

STG

Don't expect any noticeable gains from anything behind the catalytic converters other than a better sounding option and a little weight loss. I wouldn't do any exhaust options for merely performance gains.

There's so many exhaust theads between here and 6Speed it would make your head spin.

beaverlake

I agree with STG about all the threads and the dearth of real data. And what little data there is seems to indicate that you can spend a lot of bucks for little to no gain in HP or torque. I tend to be in the camp of no worthwhile gain. The sound may vary and it may or may not be a good thing but for 991s exhaust alone seems to be an investment in sound, not necessarily a sound investment.

Penn4S

Totally agree.

MagicRat

I have some 'GTS-specific' headers and cats from Fabspeed on the way to me, which I plan to dyno test. Won't be for a few weeks probably, but I'll post results here when it happens.

STG

Didn't you try headers at some point? What brand?

Plan on using PSE with the FabSpeed headers?

Fabspeed and Cargraphic quote 200 cel cats. What are OEM?

Cargraphic also has a long tube design.

HRE_Jurrian

If you're looking for a legitimate increase in power and performance from a lightweight exhaust system built without compromise, then this particular system from Akrapovič is going to be something to look out for. Here's some more info:

MagicRat

I did. Long story, detailed in 'MagicRat's modification thread'. Short version: I had their sport headers, which seemed to make the car make less on the dyno. Fabspeed are in the process of exchanging them for ones with a wider-aperture cat (which I think is what the Cargraphic ones have). We shall see how the new ones perform, but I've been impressed with Fabspeed's customer service so far.

STG

Read it. Yikes.

Why not just go with Cargraphic? Look like same $$$. They have a proven track record.

I can't believe the pics of the FS ones. Barf.

Anyone try Cargraphic headers???

http://www.cargraphicts.com/en/produ...11-models/991/

2016GTS

Would l love to see those once you get it done. Hope you get some great results!

MagicRat

I was going to, but FS offered me a pretty generous discount on the new ones and seemed like they wanted to make things right so am giving them benefit of doubt for now. We are currently corresponding about the state of the bolts!

STG

Do you still have PSE?

Wondering how Cargraphic headers would be with PSE? I assume a bit more aggressive.

I like PSE, and don't see much upside for the cost of a new full aftermarket exhaust system. Not a fan of bypass pipes.