True dual exhaust question

[qruG35]

I was just wondering what the benefit of an H-pipe or an X-pipe is. Can you just have two comepletely independant pipes running from each exhaust manifold back to each muffler or do both banks need to be connected at some point?

[NJlakeshoreG]

helps with rasping to have a x pipe! it equalizes the exhaust pulse!!

[ATL_Red_G35]

Depend on how you want it, comfort or power. You can have either

2 Independent pipe = serious drone and rasp

H-Pipe: More Tq, lil lgain HP, less drone, less rasp

X-Pip: More HP, lil gain tq, a lot less rasp, same drone.

I've tried the H, didn't like it, tried the X, didn't like it either, then tried the Perforated X and it helps a lot with the rasp.

[Gary C]

Stillens true dual exhaust system has a cross over that blends the exhaust signals
resulting in a better sound with virtually zero rasp! Borla has a simular system but
their quality and pipe size is inferior in comparison. Then you need to ask yourself do
I need a dual system with all that extra weight? If I am planning a FI system for my
G then the answer is yes. If not the extra weight isn't worth hawling all that heavy
pipe around. So then the answer is a single system which might include a aftermarket
y-pipe for a little extra flow and nice sound like my Magnaflow cat back system.

[RANC3R]

first i had a fujitsubo and now i switched it with hks hi power td exhaust i drove it last night for the first time and fell in love. the sound is pefect

[qruG35]

Thanks alot for all the great info!!!!

[DaveO]

Exhaust system sound is very subjective and I like the exhaust note of the systems mentioned above.

As for power--from our experience we find the X-pipe increases exhaust gas scavaging and cylinder charging, Therefore torque and HP with the VQ engine are increased. It appears (from our many dyno results) that the VQ engine really "likes" the X-pipe. More often than not the mean average torque and horsepower numbers favor an X-pipe exhaust system.

At a recent dyno day there were two similiarly modified revup engine Coupes. One had the current internet forum favored non-connected aftermarket dual exhaust system (say that three times fast), the other an aftermarket X-pipe exhaust system.

The results:

05 G35C Revup/6MT -- Peak Tq = 250.4 - Peak HP = 276.7 - M-ave Tq = 232.08 - M-ave HP = 187.1

05 G35C Revup/6MT -- Peak Tq = 263.5 - Peak HP = 274.1 - M-ave Tq = 240.47 - M-ave HP = 202.5

Now I agree that this was only two cars, but time and again the results have been the same. A couple of years ago we did a G35 dyno day with almost 20 cars. Of the top seven, five had an X-pipe catback exhaust system. No Gs below the seventh had an X-pipe exhaust system.

I'll close with two questions.

Has anyone looked at the 07 G35 Sedan's 306 HP factory exhaust system?

How about the G37 Coupe's 330 HP factory exhaust system?

:wink60: