hey guys i sort of have a problem, with the new 12cm non waste gated turbo and 56 mm compressor housing i can hit 55psi if i keep my foot into the go pedal for to long and i can hit about 40 psi almost instantly when i floor it, should i get a better head gasket and does anyone now how to lower the psi so i don't grenade my turbo? thanks

 

55psi is way too much. You're way outside the map of the turbo and drive pressures are probably over 75psi. You need a wastegate, either a different housing with an internal one, or an external gate.

 

crank your timing up. It will help drop your boost. I could hit 55 then i bumped the timing up now i am only at about 38 or 40 ish.

 

12cm nwg housings really don't belong on these trucks...especially if modded. If it were me, I'd turn the fuel down till I found a better solution. JMO

 

hey thanks for the input, hey ihpower how much did you bump your timing, i gonna try it

 

bumping the timing up is going to raise cylinder pressure and your head gasket will not live but 55 psi is not any better, same results in the end.

like G1625S said cut the fuel back till you can remod.

 

At this point Im not worried about the turbo, Im worried about the head gasket. I tryed a 14 CM non wastegated and I would spike on boost right away and loose boost over 2000 RPM. A 12 is to small if it is nonwastegated.
If you want nonwastegated go with a 16 CM otherwise go with a 12 wastegated.
Remember, smaller exhaust housing is good on the low RPM side, But you have to be able to flow the exhaust on the top end. Top end on a diesel is 3000 plus. A 14CM housing will kill anything over 3000RPM, if it is non wastegated. Just food for thought.

 

This is a question I've had about the 12cm2 housing. I bought a wastegated housing off of a 96 truck that has a Banks Stinger wastgate. Will this flow enough for high RPM reving? Does the wastegate actually allow the exhaust to flow by the turbine above the set intake pressure?

Wastegate technology is something I have been having trouble figuring out. Are there two kinds of wastgates? One that lets the exhaust past the exhaust turbine and another that actually bleeds pressure off the cold side?

Thanks,
Just looking gearing up for my 12 cm housing upgrade

Chass
ct

 

A wastegate bypasses exhaust gasses around the turbine wheel. There are two types: internal and external. The 12cm housing has an internal wastegate.

A blow-off valve will bleed pressure from the cold side when you reduce throttle quickly to prevent surging and keep the turbo spinning during shifts. It can't be used to limit max boost or you would end up grenading the turbo. Blow-off valves are usually used on gassers, but a few members here have them on their trucks.

 

thankyou for all the advice guys , i dont hit 55psi anymore because i keep my foot out of the throttle, but does anyone know where i can get a better head gasket, and would that help if i hit 35-40psi, or would it be wiser to buy a wastegate for the 12cm or buy a 14cm instead???? future mods will be pods, old smokey fuel pin, 3200gvs and ats manifold and of course a built tranny, probably going to keep the auto, change over to stick is out of my budget. thanks and does anyone have a slight idea and the hp and torque i might have with these mods

 

I'm running the 12 my setup and it works well for me. You need to evaluate what you really want to do with the truck. Work play or a little of both. Then you can tailor the mods to go from there.
y 0.02 Jethrro

 

The HTB2 12cm housings aren't the same as the H1C/HX35 12cm housings. I've heard their 12 acts like a 14 and their 14 acts like a 16. I believe the 12cm housings for the H1C are good to around 250 hp on a play truck, probably less than that on a work truck due to EGT's.

 

I'd just as worried about the turbo grenading than the head gasket at 55 psi. At 40 psi the HG will be just fine. If advancing the timing doesn't help, you need a wastegate.

With everything you are talking about throwing at it you should get around 320/750 out of it. You will need to spend some money on the trans to get that on the ground.

 

yes i do plan to get a really strong trans built by a reputible shop, other than the mods that i plan to do are there any more ways to get hp and torque without tearing into the engine too much??? also how much would you recommend advancing the timing? would an intercooler help make more power, i have conemplated getting the 91-93 grill so that i would have room for antercooler.

 

Advance it until you get the boost under 40 psi.

The cheap and easy stuff is pretty much done once you tweak the pump.