Cometic Head gasket

[Cranked]

Hey guys,

Just wondering anyones thoughts or possibly facts on how much boost a cometic Headgasket can handle. Including Arp 12mm head studs, torqued down to 110nm.

I have ran upto 25psi, but was warned that it becomes risky to run more then that.

However in saying that, my friend has a 1.5j with cometic, and has ran upto 30psi, making 545hp atw.

Cheers, Sean

 

[bazeng]

Sean,

Including Arp 12mm head studs, torqued down to 110nm. (80ft lbs)

Should be good for more.

I ran 37 PSI without lifting the head.
25 PSI without any issues.
30 PSI too without issues.

 

[Cranked]

What about on pump fuel?

 

[Liberoz]

The type of fuel doesn't determine weather your lifting the head or not!

 

[Cranked]

but will determine how much timing needs to be taken out of the tune, and whether its plausible to get a good result from increasing the boost further on pump fuel. No point running more boost, less timing and same power.

At the moment the car is makin 400hp atw on 22psi on pump, want to get that 11 on pump and street trim, then slicks, then race fuel.

 

[EVO-00X]

Depends on the compression ratio as well, how the head is bolted into the block, thickness of the headgasket, type of fuel, timing etc. The question has no definitive answer other than the Cometic will handle as much boost as you want to throw at it unless you're running some extreme drag alcohol NOS fed track monster lol.

 

[runuts]

Depends on cylinder pressures. Detonate it, and it prob wont last. Keep detonation under control, and it'll take plenty more.

 

[bazeng]

25psi / 30psi was done on pump fuel buddy..
making about 340kw's at the wheels.

If you really want it, get the tuner to run it on the dyno and bring it up slowly.. He should be able to tell if the motor can take it or not...

 

[Cranked]

He says that the tune, and motor will handle it, but is only concerned about lifting the head.

See we thought that we had blown a headgasket, however it turned out to be a tiny split in the front side of the radiator, that couldn't be seen until it was apart. Hence that where my coolant was going, rather then into the cylinders as originally thought.

Cheers.

 

[cblancergsr]

if you pressure tested the radiator you would be able too see anything with the radiator still in the car

 

[Cranked]

Yeah this is true, but it was all coming apart anyway.