It's more "tuning" than changing backpressure. But the two concepts cross over and mingle anyway.
But yes to the "equalizing" concept. Takes the pulses and other resonances and lets them transfer as they want to the other bank with the lower pressure.
But it's to me a better sound on Fords. I don't mind discrete duals as much on Chevy's, but with Fords I always preferred the sound of either a single exhaust or attached duals.
The crossover was the first to be tried if I remember the sequence. And it was racers and tuners like Smokey Yunick that got the ball rolling for the rest of the world. The X-pipes came about more recently (like 25 years recent?
) for packaging reasons I believe. Although the originators may have been trying too, to smooth out the transitions between the banks.
X-pipes just don't lend themselves well to trucks. Especially 4wd trucks with all their extra crap underneath. A 2wd or a car on the other hand, can run the duals closer together at some point and not interfere with as much stuff. That way they can add an x-pipe with less trouble.
But in a situation like a Bronco with true duals, a cross-over tube (or "H-pipe" as they're now called) is more compatible.
Convenience is why we see more dual-in-dual-out mufflers, H-Pipes, and simple joints between two tubes than we do true x-pipe fittings.
But peruse the X-pipe supply at Summit sometime to see the different designs.
Me, I think a "chamber" setup would be beneficial to some setups. That would be were a section of the two banks is connected by a long chamber, rather than a single tube. Think "x-pipe on steroids" or something like that.
Here's a fun watch. It's not necessarily an engineering dissertation, but it's got some great feedback:
https://www.youtube.com/watch?v=fCio5K0WfHU
Enjoy
Paul
