Cross over needed in dual exhaust?

[try2pas]

I just had dual 2 1/2" dual exhausts installed on my '80 with the LS3 engine installed also. They didn't put in a cross over between the
2 pipes. Do I need that installed or is it not really necessary? Just want it to be all it can be!

 

[spikebot 81]

Lots of opinions on this one. From what I've read the placement of a H or X pipe is important for best performence, if there is any gains to be had. If your exhaust is like mine the drivers side crosses over just behind the trany to the pass. side and then out the back. I had a raaaappp sounding exhaust at WOT with the new 2 1/2 system, magna flow mufflers. I installed a X pipe about where the cat was and that cured the problem. No performence gain was noticed. But the X pipe did tone the idel rumble down a bit and as mentioned wot does not rap and pop like before.

Way back in the mid 70s I had a 351 cleavland engine is a f100 ford truck. We installed the newest hooker headers and their header mufflers. Hooker speced to install a H pipe 1 ft behind the collectors as we did. Dang truck was fast and sounded great.

 

[KANE]

I just had dual 2 1/2" dual exhausts installed on my '80 with the LS3 engine installed also. They didn't put in a cross over between the
2 pipes. Do I need that installed or is it not really necessary? Just want it to be all it can be!

JMHO... most likely not unless you need to wrangle every conceivable ounce of power out.

Sounds like your shop thought so too if they were the same ones who did the LS3 install.

 

[EC_BG124]

Needed... no. Worth the extra few dollars... absolutely. Without a crossover your V8 is essentially working like two four-cylinder air pumps. A crossover pipe will equalize backpressure (when placed as close as possible/practical to the collectors) and virtually eliminate any exhaust drone at cruise speed. I've felt a seat-of-the-pants torque increase on every vehicle I've upgraded though I've never dyno'd one to prove it. IMO - just the reduction of the droning at speed was enough to convince me.

 

[1963SS]

Vette Magazine ran an article that pretty well summed up the question. There is very little HP or torque gained by an X-pipe (really surprised me) but a lot of noise reduction. I know I've seen other articles that documented more gains but I don't recall where. The full article can be found at:
C5 X Pipe Install - Tech Articles - Vette Magazine

 

[GTR1999]

I installed one when I ran those crappy chambered pipes a few years ago, it made a difference on the way they sounded. I've since dumped that setup and cross over. The trick I was told is to paint the pipes and install the cross over at the hottest part after the headers,not that there's much room under a vette to do this.