how much boost before boom!

[ericjon262]

how much boost do you guys think an LX9 can handle before something goes pop?

[robertisaar]

at least 12PSI, safely, if running a good tune. the headgaskets were the first and only things to go pop(multiple times) in the JonPro 3500 TGP.

[ericjon262]

so maybe since I'll have the lower intake off for a cam swap, I should go ahead, pull the heads, and upgrade gaskets. are cometics the only upgrade available?

[90BlueZ]

so maybe since I'll have the lower intake off for a cam swap, I should go ahead, pull the heads, and upgrade gaskets. are cometics the only upgrade available?

If your engine is 04+, I wouldn't bother. The stock gaskets are graphite and can handle a lot of abuse. As long as you don't have felpro HG, you will be fine

[ericjon262]

If your engine is 04+, I wouldn't bother. The stock gaskets are graphite and can handle a lot of abuse. As long as you don't have felpro HG, you will be fine

Fine to what point?

[Mars]

Fine to what point?

Fine for a while. Good tune you can go 15-18 psi with meth and good gas.

I've had mine running like that a little bit on the street. I obviously don't always run that much boost, but on occasion and its OK.

Stock head bolts, stock gaskets.

[Z26-T]

Fine for a while. Good tune you can go 15-18 psi with meth and good gas.
I've had mine running like that a little bit on the street. I obviously don't always run that much boost, but on occasion and its OK.

What octane? What concentration of meth do you use? What meth injection kit do you recommend?

[bearbear3_4]

I've been running boost on my LZ9 for over a year now, 5psi for about 2 months then 10psi since. Stock internals running E85 no boom yet.

[ericjon262]

I'd like to go to at least 16 psi, maybe more depending how things go!

[bearbear3_4]

When I had a T3 installed at 5psi I would spin the tires at 1/4 throttle and the turbo chocked at 5000 RPM. Choose your turbo wisely.

[ericjon262]

it's a GT35

Compressor trim: .70 ar
Compressor Wheel diameter: 57.36 /81.87
Turbine wheel diameter : 57.50 /73.60
Exhaust trim: .63ar

[G.I.Ceo]

This is the same turbo I'm running for my build. The boost is going to depend on a lot of things. How good is your bottom end, is anything ported, what manifolds are you using, how much flow and how big is your exhaust diameter? All this stuff matters. Whatever you do don't buy cheap! Make sure you spend the money to do it right or it will all go boom. One thing is make sure you get a set of MLS head gaskets because these can with stand boost and this is always over looked. The other gaskets won't hold up to boost. So if you do everything right you should be able to get 5-7 psi but no more then 10.

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[TGP37]

The MLS Gaskets require the block and heads to be smoothed to prevent tearing the gasket. They are great gaskets from what I heard but they require work.

Honestly, I'd rather the head gasket pop instead of something else......like a fuse.

If your head bolts are new, the bolt ports are cleaned, torqued properly, etc.......you can run 8psi safely for sure (with a factory tune and no issues). If your tune is refined then 12 psi is reasonable, the stock gaskets will hold. But if you meet over boost for some reason, better the gasket blows instead of a piston.

8 psi is a lot of added power, 12 psi is a blast. At some point your gonna spin tires. 8 psi is enough to make a huge difference, definitely noticeable.

[ericjon262]

there is no "factory tune" for what I am building! it's going to get a custom dyno tune. like I said in an above post, I would like to run about 16 PSI. which should be good for about 425 hp on a stock 3500, but of coarse mine isn't stock.

[TGP37]

Your question, how much boost before the engine pops? Whatever your weakest link can't handle.

Everything breaks in time....how fast it breaks matters. For a track car you can run a lot more boost, because component wear isn't as critical as a daily driver.

Two part answer, power vs time. I know you know this, the answer has eluded me for some time.

I'd say build it as strong as possible then calculate the max boost.