X-pipe or no X-pipe?

[J-440]

Evening all. I am getting ready to buy my exhaust system and have a few questions. First off the specs: 440EFI (soon to be blown), 3" exhaust, electric cutouts. The exhaust will be exiting behind the doors in front of the rear tires. A cross member is preventing me from running the pipes to the rear so space is an issue. I've got the mufflers pretty much picked out as I don't need them aggressive since I have the cutouts. My question is the x-pipe. Do I need one? Can I get away without running one since that will free up more space? Would there be a huge difference in how the engine would perform with or without one? The car has a FAST XFI setup so could the computer compensate for the backpressure or lack thereof? Thanks again.

[Schwartz Performance]

It's always better to have an H or X in the system. But will it be a 30hp decrease and major loss in exhaust sound? No.. You'll be ok without one if you have no space.

-Dale

[sam 74]

There are benefits to having a h or x pipe but you can run without it, lots of people do, as for the cut outs they'll create back pressure in the system when not open and that can hurt things. You're not running full exhaust so I doubt the cutouts are going to do that much for you other than noise.

[J-440]

When you say "hurt things", what exactly does that involve? I know NASCAR runs an x-pipe so obviously it does something for the engine. Or that just maybe because the rules state that they must run one. This will be a street driven car 80% of the time. I appreciate the input.

[HellPhish89]

x pipe. better scavenging than the H


short answer is the x helps keep velocity up and as an exhaust pulse crosses one side, it helps draw in the next pulse on the alternate side (iirc). i would bet that they would work amazingly well with 180* headers.

[sam 74]

By hurt things I mean your tune for one will be different for open exhaust vs going through pipes and mufflers. You want to optimize things to work efficiently with each other especially with forced induction. The cutout creates back pressure on the exhaust side of things when closed and upsets your air/fuel curve if it's tuned to run open, if you're not going or all out power for racing then its no biggie having the cutouts but you'll need to keep in mind you can lean the motor out by opening them up, and vice versa, you can richer things up when closed. I had cutouts on my car for a few years, ended up takeing them out because the made the tune go off, I was useing nitrous at the time and going lean wasn't an option for me so off came the cutouts.

[J-440]

So far as I research this subject, I'm getting a 50/50 from lots of people. NASCAR uses an x-pipe on their NA cars and drag racers with blowers do not. I've heard turbo cars need an x-pipe to control back pressure but s-charged cars don't need one. My buddies 79 Vette does not have one, but his 69 Super Bee has an H-pipe. Yet the guy from Flowmaster says that my original setup will be fine. Gotta love it!!

[HellPhish89]

So far as I research this subject, I'm getting a 50/50 from lots of people. NASCAR uses an x-pipe on their NA cars and drag racers with blowers do not. I've heard turbo cars need an x-pipe to control back pressure but s-charged cars don't need one. My buddies 79 Vette does not have one, but his 69 Super Bee has an H-pipe. Yet the guy from Flowmaster says that my original setup will be fine. Gotta love it!!

you dont need it but it is better than an H. H's are simply balance tubes. just do it