Hey guys, just wondering what a safe amount of boost is on a 97 12 valve with stock head gasket and head stud bolts? Thanks

 

I'm running around 43psi and so far so good.

 

Holset says the danger zone for turbo self destruction is 42 psi. They say at 42 the turbo is spinning at 250,000 rpm, almost double that it was designed for.
Anything over 35psi and you're just pumping hot air, raising your egts, making the extra boost worthless.

 

Thanks, so how much boost is too much for the head gasket? I.e. would anything above 30 be out of the safe zone with stock head gasket and stud bolts?

 

Seems like a lot of guys say they have no problems staying under 45.
You have to consider your timing too though. The more advanced your timing is the higher the cylinder pressures are.
This combined with high boost spells head gasket trouble.
Best to play it safe and just stay under 35 since there is no real advantage to more.

 

Forgot to mention the timing is currently stock, but soon will be bumped to 15 or 16.

 

With the stock turbo, or any turbo that is out of it's effeciency is creating high drive pressures. I bet with a bigger turbo you could run to 45-50 safely.
It isn't the boost, but it is the amount and temp of the air.

 

So, are you claiming that 50 PSI from a turbo that is designed to run in that range will be safer for my stock head gasket than 50 PSI from an HX-35 that I'm asking WAY too much out of?

If so, please explain because it doesn't make sense to me. I understand that the majority of the problem with people over-working their stockers is that when the charger is operating beyond it's range efficency, it really is just overheating the air. Is there more to it?


Thanks!

 

Dont need a ton of boost to make good power either. With a stock 215 plate slid all the way to the rear and 50psi boost, I can put down 300hp to the ground. With 100 plate in same position and boost I can lay 500hp to the ground. Proper pump timing and tuning can make wonders happen. HX35 is fine IMO. Also agree with above. 35psi max IMO on a HX35. Might be a good idea to good ahead and retorque the head bolts as well. You can abuse those HX35 turbo pretty hard before they go.

 

So if one were to put an adjustable boost elbow on and regulate it a 35 psi how much of a good difference in EGT's to expect while towing?

 

Yellow. it doesnt matter what turbo you have 50psi is asking the head gasket to leave.. the limit is around 40-45 psi on the head gasket period. and lets not mention that hx-35s dont like even 40lbs of boost anyway. but even if you changed turbos it would be worse as the air wouldnt be as hot which means dense air which takes up a lot of volume in the cylinders.

 

Yellow, the reason a small Turbo running outside its effective range would kill a HG faster than a larger one running inside its range is the amount of heat each puts into the charge air. When you push them outside their envelope, things heat up fast.

 

You could always put a larger exhaust housing on the turbo if you would like.

 

I have a buddy pushed 50 psi, stock HG and studs. And another buddy pushing 65-67 with the stock HG and studs. Niether was ringed or anything ?

 

Give it time...