Horsepower increase for just X-pipe?

[John@Roc-Euro]

What about the scavenging gains from x-pipe???

Not post-catalyst on these cars. In a very simplified sense, the X only works to scavenge if it is at the correct location downstream (often limited by chassis underpinnings) and has a super clear path back to the exhaust valves. IF you were running headers, and no cat, and could place the X in the perfect spot, I could not deny that scientifically speaking, there could be an impact. We are also likely on the same level as taping body seams to make your car more aerodynamic. Yes, it technically works, but to what extent and what level is it effective? Stuff like that. Either way, I am solely referring to this car and platform for the specifics.

Can't tune for it, you can't gain from it... /end thread

Not always true, that's just where the best gains are found.

So your saying exhaust systems have zero quantifiable gains?

No; A specific component of an aftermarket exhaust system is not always a constant improvement. We see light gains from any exhaust system that improves flow and reduces restrictions versus the OEM pathway. The X-pipe is not going to make more power on these cars in the existing aftermarket options OVER another aftermarket option with similar specs asides from the crossover.

[saxon]

No; A specific component of an aftermarket exhaust system is not always a constant improvement. We see light gains from any exhaust system that improves flow and reduces restrictions versus the OEM pathway. The X-pipe is not going to make more power on these cars in the existing aftermarket options OVER another aftermarket option with similar specs asides from the crossover.

Ok, I think the op meant a stock exhaust with x pipe mod compared to an aftermarket exhaust.