exhaust size question.....

sps21112

New Member
hey guys just bought a holset he351cw turbo and had a question while i wait for it to arrive. That turbo has a 4 inch outlet on the exhaust side and i was just wondering if i could make a 4 inch to 3 inch downpipe. Or do i have to run 4 inch all the way back? Thank for any advice..
 

Accel.speed

basically, i like fast!
Normally people like to run a 3inch exhaust with a turbo (unless you're pushing a lot of power). So Yeah I would do a 4 to 3 conversion how ever you like.
 

Muckman

Not a M0derator
Lol I dont think you're going to enjoy the performance of a diesel turbo meant for a 5.9L engine on a 1.8L engine. The fact that its designed for a 4" outlet could be an indicator.
 


sps21112

New Member
I bought the turbo because it flows the same as a EFR7670 = 60 lbs/min and more than a GTX3071R = 57 lbs/min. And spools just as fast if not faster than a gt3071r. And your right there made for diesel engines, but thats a good thing on a daily driver because everything is beefed up. Those turbos are made to last 500,000 miles at 30+ psi on those trucks. The dsm guys are using them so i figured id try.
 


Ghost75

Consumer of Apples
Turbo's that are made to push big boost aren't happy pushing really low boost (correct me if I'm wrong on that) and I doubt you're going to do 30psi daily.
Our motor is rather petty in comparison, and isn't going to produce the gases.
 
Also kep in mind that diesel turbos aren't designed to be spun over 3-4k rpm.
Engine RPMs aren't the kicker, it is the volume of air being pushed into the exhaust housing that is key.
Turbos themselves spin much faster than 4k rpms.
This comment confuses me.
 

Muckman

Not a M0derator
Me too. Very interested in seeing the boost curve and dyno graph when you get it tuned. Keep us posted.
 
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