how much is to much ?

[stakedd]

Hey all, finally figured out how to log in to TDR (7 mo later). I am currently working on a twin t set up for the truck and just wondering how much boost it will take to blow the stock 260K head gasket. currently running 30 PSI with no problems. will use either HT3B or HX50/55, whatever I find first. the small turbo will be HTT3/12. any input as to how soon after TT's I can add O ring head, cams, and port job to profile would be appreciated

 

[Smokey 01]

I blew mine with 35 lbs out of the stock turbo with stock timing on my ol 1990.

 

[Greenleaf]

What year is the truck? The later model head gaskets are known to be stronger than the first however there are exceptions to every rule. Ask Bill Gilbert about his boost on the early truck had gasket.

 

[stakedd]

truck

my truck is 91. 5 w inter cooler. probably old stile gasket

 

[Greenleaf]

Newer style.



You could get lucky and retain integrety with 50/60 boost then again you like to visit LasVegas too right????



You'll be safe with 30..... 40 possibly. 50 and you'll be wanting to get set aside $$ for a gasket/studs etc. etc. etc.

 

[bgilbert]

Timing, heat cycles, warmup times, and drive pressure have more to do with HG integrity than boost. 30, 40psi of boost with a hx35-12 is not the same as that amount of boost out of a hx40 or bigger single turbo. You'd be more likely to blow a HG with the hx35-12 and its high drive pressure than you would with a hx40 at the same pressure.



You should take care of the head and get head studs before twins.



For twins, a hx50 and hx55 is probly too small, you'll want to find something bigger, ht3b, hx60, ht60, s400 etc.

 

[BushWakr - RIP]

I think that the boost levels are also impacted by the EGT's... . if both are too high you'll pop the head gasket sooner...





pb...

 

[MMiller]

I'll add something else. Make sure the engine is up to operating temp before pushing boost over 10 psi. I'm pretty sure 30 psi of boost on a cold day, before letting it get to operating temp took out my head gasket.



Michael