I’ve been doing some additional research on 180-crossover exhausts, specifically on LS engines. While the C7 video in the last post has an LT and I have a LS7 my engine is a custom build and supercharged like the LT, so it hopefully provides some insight into what mine might sound like. In any event, that car has a build thread and I was able to determine how it was fabricated. As I previously mentioned, the optimal approach for scavenging and sound is a round collector with the tubes firing in a sequential clockwise or counterclockwise manner. As can be seen in the picture below the fabrication is top notch and flat collectors were used for fitment reasons.
I was curious if the fabricator was able to optimally sequence both collectors. As can be seen below, the top collector is as good as you can get with a flat shape, but scavenging/sound won’t be optimal between B and C. The bottom collector has two discontinuities; B-C and D-A. Does it matter? Probably very little, but a round optimally-sequenced collector would likely sound a little more refined.
Here’s another video of that car. The first 30 seconds has an x pipe and the following 30 seconds has no merging after the collectors. The owner preferred the version without the x pipe so that part of the exhaust went in the recycle bin. Interestingly, Abe fabricated and installed an x pipe in a Ferrari 812 Superfast last week and everyone preferred that sound.
The following picture shows the version with the x -pipe.
Here are a couple of other video/sound clips. All of the cars are white and I’m fairly sure they’re all the same car. I don’t think the first video has an x-pipe and the last two definitely don’t have one. In any event, they provide some inspiration.