4 inch exhaust question
 

Is the 4" stainless marine exhaust pipes measured by ID or OD ?

Re: 4 inch exhaust question
 

Pretty sure that is OD,

since the hose is measured ID

Re: 4 inch exhaust question
 

hi-perf

It would be the OD. Tubing is measured by the OD, example - exhaust tubing and Pipe is measured by the ID example - Black pipe.

Re: 4 inch exhaust question
 

thanks guys

Re: 4 inch exhaust question
 

They are 4" od and 3" id on the silent choice risers.I lengthened mine to make them long wet risers and left the inside tube 3".I dont know if the long wet or long dry risers from stainless marine have a larger id.I was concerned about the diameter being to small but it seems fine in a 502/500 horse aplication.