would it really matter if i do straight pipe all the way back since im in a 250 or should i add the x pipe for more torque im assuming?

update on page 2!

 

It won't really matter. The difference between an axle-back and a full true dual exhaust even on an IS350 is like 5 horsepower.

Well, it'll matter as far as failing emissions if they do a visual for cats...and it'll probably matter for changing the sound... but it's certainly not worth it for power gains, especially on a 250.

 

well im not worry about emissions. and i know power gains won't be crazy but just wondering if some back pressure would be better then no back pressure. This would be on a true dual set up of course.

 

It's a myth that a car needs "back pressure"- what it needs is exhaust velocity

Here's a good explanation of the issue-

http://www.thumpertalk.com/forum/sho...d.php?t=659727

 

awesome !! thanks a lot

 

Whether you do straight pipes, x-pipes or a simple axle-back the only difference between these is noise. You won't gain much power and if you do it's minimal to the point where you won't notice it. It's all for noise..

 

Here's a piece I wrote on this a few years ago. It's a little Scion tC specific in spots, but the general principles are the same.

AFA the X pipe - I would do it. It will help mid-range torque noticeably even if the peak numbers don't show a big difference.

 

I'd still like to see the Burns Y-Pipe to single 2.75-3" exhaust to finish. I was going to give it a shot but I'm already on my third exhaust not and am not spending any more $$$$ on exhaust. Some one should pick up some good gains because V6 motors don't have the best exhaust velocity, just look at the headders that never worked out.

 

hmm.. i'll just try something new and see where that takes me.haha.

 

Yeah, I had the same thought. A single pipe would look different and would need some cosmetic help with the two cutouts on the rear bumper cover. I'm still not 100% clear on why NASCAR Cup cars run two pipes with an X though. the only thing I can figure is they need the ground clearance and it's easier to do with two pipes instead of one and the performance difference must be zero. If there were even 2 hp more running a single pipe, I'm sure they would (unless the rules state they must have two...)

 

Well with V8's you always have at 2 pistons firing so get scavaging. V6 is not in the same boat. One piston fires at a time so headders make no differance. This is per head (bank) of course. So just having a way to help velocity from scavaing from the other head would help gains some. I always thought a Y-Pipe would make a better diff. on V6's just because the velocity just isn't their and keeping it all in the same pipe would help keep exhaust temps up which also keeps velocity up.
With an X-pipe your cooling the exhaust more than you would with a Y-pipe setup.

 

Hey if you are a striaght pipe can you post a video of it i wanna hear it before i do it i wanna know if its worth it

 

will do waiting on my cannisters to come in.

 

ask UV... he has straight pipes... i drove his car... god damnnn that shiet is loud... haha

 

When I took off the stock exhaust and put my custom one on, it added much more than 5hp. I raced a stock IS350 and walked away from it and my only mod is my exhaust (for now ). Stock I lost to a E46 M3 with exhaust, but after my exhaust I pulled a 1/4 car from 40-90. My exhaust is a dual 2.5" with an X-Pipe. There are also no CATs on the exhaust.