Horsepower increase for just X-pipe?

[spawn350]

Tons of threads, but most talking about the sound. If I keep the stock cat-back but add a X-pipe and maybe hiflo cats, any info on HP increase? This would be on a stage 2 car. Thanks!

[saxon]

I don't have solid evidence of stock to x pipe, but I did get my car dynoed one week with the x pipe and the next week with the apr exhaust and I was within 2 hp (x pipe made more but most likely due to dyno variances and temperature)

[spawn350]

Got it. Thanks! I'm looking for HP and not a noise maker. Hopefully some others will chime in as well.


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[jran76]

Got it. Thanks! I'm looking for HP and not a noise maker. Hopefully some others will chime in as well.


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No real gains with an X-pipe. Most exhaust mods outside of test pipes are not going to add much power. A full exhaust may add a few HP, but nothing substantial. Same goes for headers when compared to test pipes, and both have their obvious drawbacks.

Getting rid of the stock air box will probably be the easiest thing to do to gain some power.

[87rangermud]

If you think there's no gain from an x pipe or headers you've been fooled there def is

[John@Roc-Euro]

If you think there's no gain from an x pipe or headers you've been fooled there def is

Um, bit of a difference between these here items.

X-pipe added into 3.0T catback? Zero quantifiable gains.

Headers or other catalyst replacement device? Different story (and a loaded conversation)

[87rangermud]

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

[jran76]

Um, bit of a difference between these here items.

X-pipe added into 3.0T catback? Zero quantifiable gains.

Headers or other catalyst replacement device? Different story (and a loaded conversation)

Exactly....

[RecklessactN]

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

[saxon]

Um, bit of a difference between these here items.

X-pipe added into 3.0T catback? Zero quantifiable gains.

Headers or other catalyst replacement device? Different story (and a loaded conversation)

So your saying exhaust systems have zero quantifiable gains?

[Schadenfreude]

So your saying exhaust systems have zero quantifiable gains?

Probably a very small delta (which depending on variables like rpm etc etc could be up OR down) and that delta is likely small enough to be absorbed by the dyno variances and standard error of measurement for each particular dyno. So in the end, not quantifiable is likely.

For example if std error of measurement is +/- 10 hp then a gain of 3 hp would be effectively undetectable since every dyno run would give you the same 20 point spread around the "true" value and the 3hp change would disappear within that 20 point value uncertainty

[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.

[John@Roc-Euro]

Still just sound.

[saxon]

Still just sound.

I made the exact same power with stock exhaust an x pipe add I did with full apr. So if the x pipe is just sound I'd argue all exhaust are just sound

[chaos2984]

I made the exact same power with stock exhaust an x pipe add I did with full apr. So if the x pipe is just sound I'd argue all exhaust are just sound

yes this guy had it dyno'ed and had no results in gains from going from exhaust with xpipe to full apr exhaust. I almost bought his factory system from him. Im doing this mod. I picked up a factory complete exhaust and going to modify it to put on my car with an x-pipe.