What sort of compression ratio are you running? It mightn't be combustion pressure that blew the gasket, it might be detonating, in which case, you'd actually 'want' the headgasket to be borderline, so it acts as a fuse before you do more permanent damage to the engine. Which would mean the 'real' answer would lie in dropping the compressoin ratio down to a safe level.

Problem can occur where it's detonating, but it can't be heard over the noise of the engine/turbo in general. This _might_ be happening (and I'd tend to worry that it might be if it is a std engine/std compression and 10psi on top.An a12 (by virtue of smaller bore) would be relatively less likely to detonate at the same boost/compression ratio, even more so depending on chamber/piston shape))

Personally, I'd try just a new std gasket on there and running water injection, and see if the head gasket holds up. If it still lets go, it's a gasket/clamping issue, not detonation. A relatively cheap way to test that out without risking breaking bottom end parts.

Ive been running 12 psi through a 20,000 km old standard a12 (standard head gasket) for nearly 2 years it puts out 106hp I've had no troubles with it the motor just changed out first broken diff this week. its probably done 6-7000kms with turbo on it now. I had it at the drags about a year ago with a 3.7 diff in it it only got 15.6 sec 134 kph in 3rd gear @6800 revs I couldn't get it off the line quick because the clutch would slip or wheel spin
You should keep it and spend some money on a tune I got mine done at Ova boost in Malaga

Cheers Brad

lol

Quote:

Quoted for posterity when the first second and third things break and cost alot more to fix

cheers dude ill give ya a buzz on the weekend

g'day mate. if your serious give me a call. number is in my profile. dont waiste your time and money with head studs unless you insert the pistons to handle it

stevo the tune is perfect it runs realy nice . on the street it was going sweet but at the drag's i didnt get to enjoy the car has first run she shat her self on the start line :(
my t50box has a hd clutch and different flywheel .its not a daily just a fun car ( was ment to be a cheap fun car lol )
is your motor stock stevo?

i have a water inj setup for the sr20det ute maybe might borrow it .but then again i dont wanna touch the tune has i cant fault it

yer seen some pic's of flywheels letting go arrr !

cheers for all the info guys still realy keen to hear form people that have ran turbo a12/14/15's for a while and wat they recomend :)

have to disagree with your veiw's on skylines there neil newish jap cars are very thrash friendly :)

Personal opinion here

Pull the motor apart now and check the bearings for signs of detonation
Chances are you have already lunched the pistons and rings anyway

When your happy with the bottom end put it back together

If its got stock pistons in it now your as decompressed as I'd want to go without making it doughy off boost

With all those crazy injectors on it maybe you should make one of them pump a methanol/water mix to help cooling intake temps and providing more bang for your buck

Then get it tuned to suit

Thats what I would do if it was me and you weren't looking to spend huge on reinjecting it and building it for boost

As for the clutch and box...I'd use the T50 but its not going to handle abuse much more than the stock box
And if you use the clutches Dellow says to use they use the standard A pressure plate so its no bigger or better than what you have
Unless you get the flywheel redrilled for a Toyota 200mm clutch like mine is
And if you lighten the flywheel it will rev faster.... might take your ankles off if you take too much off it though



And Skylines do break... often... and they cost more to fix

It was quite fast, to say the least. I agree with Jordy on the 14second quarter time.