Tubro Down Pipe Sizing

Diesels like to breathe. Larger the better. To constrict the pipe by going smaller will rob you of necessary horsepower.

Other thing that helps is more intake, less restriction for air comming in the better.

 

You can "play" with the size of the pipe, too big and it will hurt torque numbers unless your engine is really modified.

 

You've got to maximize the effects of "exhaust scavenging" with the right diameter and length pipe. If you're a gearhead you can really overstimulate your brain on this subject, EVERYBODY wants the maximum effect. You might try Googling it, it's TMI to get into here.

The wrong size pipe (diameter or length), a split for dual pipes in the wrong place (too close or too far from the turbo) and a bunch of other details can change the torque curve or mileage in your motor. Sometimes not for the best.

Interesting subject..

 

I would have to say 5 inch is a pretty good size. Seems most come stock with 5 inch. Keep in mind that getting a free flowing muffler of some sort will help more with lowering your EGTs and getting a better response out of your turbo/s. I would say go with a 5 inch DP and go with a good set up flow through mufflers.

 

Sorry, not trying to hijack but I have be wondering something. I have the wrap to do mine from the beginning of the flex pipe off the turbo all the way back under the cab to the bottom of dual 5" stacks. Haven't done it yet though. With dual straights do I need to worry that the wrap will negatively affect my EGT's? I don't have a pyro to tell me. Just trying to lower my under hood/cab temp and reduce the fire risk from the chaff that builds up on my tanks and surrounds the exhaust.

 

A really great insulator (not sure if you can get it) is fiberfrax. Used it on miniature boilers in the Live Steam hobby. I highly recomend it if your going to insulate your pipes.