I had a thought today while I was looking at the exhaust on a semi truck. On those trucks there is a short run of flexible exhaust pipe right off the manifold (or turbo) and it runs to the rest of the pipe and stacks. The stacks and all the rest is hard mounted, no hangers. So I thought, y can't I do this on a car? The only concern I have is that the pipes would expand lengthwise when hot. But, I think it would last longer of I ran a short piece of flexible after the Y pipe and hard mounted the rest.

P.S. I work with semis a lot, and those massive, powerful motors run SINGLE exhaust. Even the ones without turbos. The twin stacks are JUST FOR LOOKS.

 

Trucks use it because of movement between frame & body (prevents cracking of hard tubing). I used some stainless flexible between the headers and mufflers on the '57 because the shops didn't want to bend 3" pipe for me (without charging an arm & leg, that is).

There really isn't any reason to use it on our cars, where prefabricated parts are readily available.

 

Yeah, I really thought some of the guys would go crazy about the single exhaust thing. Guess not. Just a thought

 

well if your gonna bring it up again... why does smoke come out of both of the stacks. is there a Y pipe that seperates the single exaust to go through both of the stacks?

 

Yes, the exhaust is usually 4-5 inch!!!!! This runs to a Y that feeds the stacks which are also 4-5 inch. That could explain why semis run whimpy or no mufflers, cuz of all the expansion in the stacks. You're right though, the flexible pipe is because of the air-ride cabs (the cab floats on shocks attached to the frame). Still semis cheat a lot, they use flexible pipe where ever there is a difficult curve. This seems to work fine for them.

 

5" stainless flex is about a dollar a foot.

Figured I'd add another post to my total