Just curious how much boost is normal for a 96 12 vavle that is stock. Not that Im complaining but I have hit 26 lbs when on it. That seamed a little high compared to my old 93 12 vavle. thanks guys

 

a 12 valve can range from 24 to 29 pounds of boost peak

 

your stock turbo is safe all the way to 35 psi, after that it starts pushin hot air.

 

cool, thanks again

 

Above the HX-35 boost pressure isnt considered till about 45, Then after o-rings and studs , 80+ is considered safe...After a girdle and 24v rods or another rod.....it's pretty much endless

 

Safe isn't the right word. Useful is more like it. And anytime you compress air your pushing hot air. Your also only correct part of the time.

Turbos work off of pressure ratios. Not pressure. A 3 to one pressure ratio is not the same boost pressure at sea level as it is at 5k feet. and since turbos care more about pressure ratios than boost pressure...

The formula is PR=(boost pressure + Atmospheric air pressure)/(atmospheric) so quick math lesson.

(35psi+14.7)/(14.7)=3.38 pressure ratio. The same ratio at 3k feet (approx. 12.8 psi) 3.38=(x+12.8)/(12.8)(OH NO! ALGEBRA!) which equals around 30 psi of boost. and the boost pressure will decrease as elevation goes up.

 

i love algebra......

 

Sounds like some really good info but I am new to all this so all of the above might as well be typed in french thanks for the info, I am going to try to make since of all of it now

 

Its also not just boost its the volume of air moved too...i only hit 38 on a 24 valve and keep blowing the head gasket with studs.. i could make 43 with stock turbo easy never with a problem..

 

whats your torque sequence? and did you check the straightness of your head and block? Those are usually the cause of head gasket problems. Especially at low boost levels. I've hit 40 psi on my 62/71 with the stock head bolts. Not saying that one of these days I won't looose mine too ... Thats been my hardest decision lately. Do I want head studs or an xbox 360? I think the head studs win.