I would like to know how much boost the stock head gasket and studs will take? I need the limit on pulling a steep grade for a mile or two and also what spikes I can get away with. Thanks.

 

till it leaks.

I've heard not above 50psi. boost pressure isnt the only reason for blowing gaskets. generating lots of boost before fully warmed up. timing is a bigger killer than boost because it has more affect on cylinder pressure, which is the gasket killer. timing mods whether they be modules, programmers, rocktech, tone ring mod, etc.

I've set mine at 45psi. until I stud it.

 

I've maintained 45 psi for moderate lengths of time. My problem is that whatever I'm doing, 45 psi speeds the truck up quickly enough that I reach unsafe speeds before long. I've probably maintained that boost pressure for 20 seconds or so pulling a trailer up a hill. I crested the hill at something like 85 mph pulling a 34 foot travel trailer. I have stock head bolts and gaskets.


*Edit* I've also been fairly hard on the truck in other ways besides the boost. I have my static timing cranked up to 16.5 degrees, and I've sprayed nitrous on it a number of times at that timing spec and 45 pounds of boost. Just like a gas motor, hit it with some nitrous when it's running rich and it gets with the program right quick. I don't know if boost increased on the bottle or not-I wasn't watching the boost gauge any of the times I sprayed it.

 

Thanks guys. I didn't consider timing at my alititude, thanks. After talking to a lot of people and reading a great deal I have decided on the SPS62/14 along with ATS intake and exhaust manifolds. With those and everything else in my sig I think I'll be a happy camper. The SPS 62 at 45 PSI should be sweet and very efficient.

 

i love mine. towing is something else. egts down under a good load, power is plenty(but never enough). you'll love it.

 

that is the exact turbo I have,, it is awesome,,but one caveat,, I have a small problem of running out of air at the 1900 rpm under heavy load..... which then starts the turbo into serious barking situation,,, so I am going to try and up the hp in the 2000 2100 range so that it will just pull without going down that low.. 2000 rpm = 60 mph

 

I would look at HTTs new pro street 62 and get the 12cm exhaust. I should flow more at mid rpms and spool sooner. Where as the 14cm will flow better in the upper rpm range but will spool slightly slower and not cool as well in the mid rpms. Either should support 500hp+.

 

I hit 60 psi all the time...

I would not worry at all about 50 psi.

 

I have seen spikes to 60psi on mine, my II SPS66 wastegate is set at 55psi and I can keep it there for most of a 1/4 mile without any issues so far on stock head bolts and head gasket.