How much power does an H pipe really make?

[Edster]

Its time for a new exhaust. I've heard that they make about 3-5 hp and improve midrange torque. I've also heard they make a big difference. Is this difference really noticeable? Is it worth the extra cost for a street driven car? does it improve fuel economy and if so is it a big difference? I'm not racing the car just cruisin around. I know that on my Sportster when I removed the H pipe it seemed to have better mid range and upper end. Of course it is and etirely different animal in comparison. I really don't think it will make a noticeable difference on a V8.

 

[gregski]

why don't you dyno your car before and after and put all of our doubts aside, I agree with you that it won't be that much, but the proof is in the pudding, I know dynoing will cost you extra money but you can file it under lessons learned and it may be an eye opening experience, of course if you change the pipe diameter at the same time then all bets are off now there's more factors involved than just going to H pipe, also if you change mufflers, also if you change exhaust manifolds for headers, its really easy to get the domino effect on an exhaust upgrade, good luck and keep us posted, pictures don't hurt either if you plan on doing the work yourself

 

[2+2GT]

According to Hot Rod testing years ago, the crosstube was good for an increase of 5-15 hp, depending on how the rest of the system was configured.

 

[Edster]

I plan on going from 2 inch to 2-1/2 inch system and will use thrush turbo mufllers (mainly cuz I like the way they sound).

 

[tx65coupe]

The H pipe equalizes the exhaust flow and makes it sound a bit smoother too. Like was already said, its not going to increase performance substantially, but will be better. I added one to mine when I put on all new exhaust. I feel it is worth it.

 

[blown65]

I have an X on my car and like the sound of it.

Tested at the drags with both the X and mufflers and with just header extensions. Even with the weight loss of the exhaust system I went pretty much the same MPH and ET.

 

[Edster]

Thanks for the info, I like the rougher sounding idle of individual exhaust better, and if i gotta pull the trans its easier w/o the H-pipe