Will going from stock to a mildly larger turbo like a 62/71/13 give you higher cruising egt's with lower boost at cruising?

Would this hurt or help mileage.

With my truck i am at 10psi, 2200 rpm at 70 mph...cruising at 80 i am at 2500 and around 18-20 psi. Seems like a turbo with a "looser" exhaust housing would help me and us other short legged G-56 guys out.

I remember MY 97 powerstroke had a 1.15 A/R stock turbo and it cruised at 2500 rpm at 70 mph and it only took around 5-7 psi boost....

The high boost seems like it hurts my interstate mileage?

Am i way off on my thinking here?

With my cam i can be at 30 lbs of boost by 1500 rpm in 6th gear now...seems like i could spool a "looser" turbo?

 

i have a 64/71/13ss for sale

the spool is great and it will support decent horsepower

pm if you want

 

Naw, you're about right. I see about 3-4 psi @ 70mph up to 7psi depending on where I'm driving. Egts stay around 650* cruising and will jump up to about 900* climbing a decent hill unloaded. When towing my egts never see past 1200* and thats on a hard run. Spoolup is great for the truck, @ 70 the 62/71-13ss is right in its powerband, so spoolup is pretty quick and responsive for me. Believe it or not, my mileage is beter with my setup now than with the stock turbo. Maybe its because the betas are more at home now than they were on my stocker.

 

MY thinking is my mileage would be better just due to all that air trying to squeeze through cruising. At 70 mph im at 2200 rpm, 600-650 EGT and 10-12 lbs of boost on flat ground!! At WOT i cant get my EGT past 1350 with my JR on 100 horse.

Why did the older trucks come with larger exhaust housings? didnt alot of the 1st gens come with 18cm exhaust housings? Emissions?

 

If you give it WOT in 6th gear from about 1200 rpm..about what rpm does your turbo start to light?

 

It'll really start pullin at about 1800rpm, but the hard fueling down low picks the truck up to its boost pretty quick.

 

i wonder if them would work ok with a 24v manifold....this is on my to do list for sure
http://www.cumminsforum.com/forum/3r...3rd-gen-2.html

the sound is awesome

 

Heres how mine sounds with it and a Flo-Pro Muffler. Sounds great, and the noise is a whole different experience.

 

is that with a 3rd gen manifold?

 

Yes sir, haven't touched the manifold at all.