Exhaust Pipe

[Ben_W]

I have a 44 HP Yanmar Engine in my McCormick GXH45. I noticed the exhaust manifold outlet appears to have a bit wider inside diameter than the exhaust pipe. Would there be any problem going to a larger ID of exhaust pipe? Or, is an engine tuned to a particular size? Also would it gain me anything? Thanks

 

[thcri]

I would keep it the same. I am sure Yanmar and McCormick designed it that way. There is suppose to be the right amount of pressure on the outlet side.

murph

 

[normde2001]

You might gain 1/10 of a second or so in the quarter mile, but otherwise not worth the effort.