i have a cutom TD exhaust on my g35. its basicly 2 straight pipes from the cats back. i was thinking about adding a X pipe. what are the pros and cons of an x pipe?

 

It scavenges better, it should help...DO IT.

 

would it sound any different?

 

yeah, it will sound like a 6 cylinder instead of two 3 cylinders running next to each other....if that makes sense? Which it probably doesn't, b/c i'm having trouble making sense of it.

Someone [...] help me [...] please?

edit: I'm sure you will see some small gains though, nothing big...it's hard to see large gains on a stock N/A setup.

 

I have an Invidia G200 and your comments are correct. I added an "H" pipe to mine, and it smoothed things out at idle. At idle it sounded like you said, two 3 cylinder engines. It also had a lop. The "H" corrected this.

Lou

 

In an N/A car, a little back-pressure is welcomed for a smoother idle + low-end torque. The X-pipe will deliver on this. The problem with TD exhausts on an NA car is that it expels the exhaust gases too quickly. While this is ideal for a FI, it is not for NA.

 

how will an x pipe sound? raspy?deep? throaty?

 

I think you mean...

Exhaust volume increases.
Exhaust velocity decreases.

 

Exhaust pressure on either side will be equal after the X-pipe. Not certain if this is a performance advantage.

 

would an h pipe be a better option?

 

I guess you have diagnosed this "problem" after seeing hundreds of dyno charts with true dual exhausts losing power on N/A?




I agree that the X-pipe will help, but not because of any of the reasons this guy just said.

I guess the backpressure myth will never die!

 

X-pipes are more efficient at scavenging exhaust gases, and therefore increase and balance flow. Some x-pipes are made better than others, and do a better job. In an H-pipe, once the pressure builds in the H, the benefit gets stagnant - hence a reason that H-pipes can deliver a little better bottom end, but loose at the top.

At higher RPM rates, X-pipes are more efficient, and can provide for more horsepower, as long as the rest of the exhaust system is designed properly as well.

Years ago, I did some tests on H v. X and found the X to give more HP overall, by about 2-6 HP, depending on mods. For an FI car, the X is best, as the more flow and better scavenging, the greater gains overall. Keep in mind, these test were done on 6 cyl..not 8 cyl..so I don't know the difference of that rate, which the former is more on topic anyway.

Rick