Exhaust stack diameter

[bluebird90]

Need some opinions here, I'm installing an exhaust stack at the back of the bus. Existing exhaust is about 35 ft at 4 in diameter. I will be adding about another 13 ft of stack and pipe. But I'm concerned about causing too much back pressure for the engine. Has anyone continued to use the 4 in pipe for the stack or go larger diameter for the stack itself? Not interested i having the exhaust at the side or having to change the whole system.

Mechanical DT466, 210 hp.

 

[o1marc]

Need some opinions here, I'm installing an exhaust stack at the back of the bus. Existing exhaust is about 35 ft at 4 in diameter. I will be adding about another 13 ft of stack and pipe. But I'm concerned about causing too much back pressure for the engine. Has anyone continued to use the 4 in pipe for the stack or go larger diameter for the stack itself? Not interested i having the exhaust at the side or having to change the whole system.

Mechanical DT466, 210 hp.

Am I wrong , or could there be a 30' difference in exhaust pipe length on the same motor whether FE or RE? I think the diameter of the pipe doesn't make much performance difference due to length, it's as free flowing as it's going to get.
Where were you planning on running it?

 

[Booyah45828]

4 inch is plenty, especially after it's run 35 feet to the back of the bus. At that point, a lot of your heat has gone and your velocity has gone with it. You won't get any pressure increase by keeping the 4 inch.