Fanged03

I seen somewhere on here that when the stock turbo is making 35-36 psi it could crap out? Is there any truth to this? In this cold indiana weather with my H&S on mild it'll make that no problem. I have set the defuel at 35 psi but when floored from a stop it'll defuel pretty quick and go in and out of defuel. Is this something to really worry about? I don't want to hurt my turbo but love the power boost with the cooler air. What should I do?? keep the defuel at 35 or not? I kinda want to see what she can push but don't want to hurt it either. She only has 4k on the odometer and I don't want to put all that junk back on to try and get warranty work done.

Brent

djcheez

you will get several different answers on this. some have blown headgasket or turbo on stock trucks. Others can push the limit running 38 psi of boost and dont have problems. I would say anything above 32 you are gambling. however (knock on wood) i have run 36-38 max consistantly for 30k miles and havent had problems. prolly will put some 625's in for added security

Stargeezer

I wish I'd had a boost Gage BEFORE I deleted everything. I just uploaded the mild/no turbo tune and it will hit over 35lbs in a heart beat as it drops a gear into passing mode.

Knowing what the boost was before I swapped everything out would be comforting (or scary ). I can't do the studs right now and we are going to pull out with the RV in tow in another week.

Blowing the HG as soon as we pull out of the driveway would put a very dark cloud on the trip.

New2Diesel

I'm with you on that one brother.

I say set defuel at 30PSI. The H&S is not immediate, and blowing a HG is!!!

Even if you set defuel at 25PSI, your truck will still spike at 35. Trust me, I have tested this.

Even the EGT's are the same way, I set my defuel at 1200 and it still got above 1600. The H&S is a little slow but I am not at all saying its bad. I refused to take stock studs over 30PSI unless the factory bolts were torqued an additional 10 ftlb

Bullet112233

I asked this question about 2 months ago and got nothing but arguments over the engine and head gasket, but only a few opinions on what to set defuel at. I set mine at 35 psi and cuss everytime I defuel. Going to put some studs in soon and let her have 38!

Mike Holmen

I've run a few times to 43psi on mine, nothing has happened yet, still stock head bolts.

Lots of issues cause turbo issues, most failures are electronic failure from excessive heat.

mikenadalin5.9

I just put and edge juice cts and when its on the stock setting i can push 30 psi when i jack the chip up to 100hp i can push 45+ boost and nothing has happend yet. it is a good idea to beef up the head bolts and the gasket bc we all know that the head is going to leave a good dent in the hood when she blows.

Lil Dog

Head gasket issues on the 6.7 are more to do with timing than boost.

Mike Holmen

Lots and Lots of reasons for head gasket failures. I had to deck one 6.7L block 7 thou just to get it true again. The CR heads typically need 4 to 8 thou cut. Once they have been trued up and straight, head gasket can take more abuse. The proper finish on the head and block is also required for a decent seal.

We did a 6.7L head stud install, on a newer 4th gen truck (first time into valve cover, but was deleted), a few of the bolts were way looser than rest. One was almost finger tight. The exhaust lash on a few of the valves was 30+thou and intake was 10-15ish for lash. We lashed the valves to standard 5.9CR specs, egt's dropped.

How warm is the engine prior to pushing hard down on the throttle? I usually wait till the truck is fully warmed up to go over 10psi. Even the best efforts can't over do factory might have messed up.