hi, im after your guys thoughts about how i go about lowering the compression on my engine without going as far as fitting forgies or machineing the top of my pistons. ive heared of using a thick headgasket but where do i get those from??? what brand are they??? how much to they cost??? and ive heard of stacking two factory headgaskets......sounds abit dodgy doing it that way???..... has anyone done it??? pros and cons??? or do i spend the money and get a thick copper gasket made??? your guys thoughts on this would be greatly apreciated!!!

have a look here
http://z4.invisionfree.com/lexusaltezzaclu...7130&st=0&#last
xnickX and finny were discussing the same/similar thing. I believe madaltezza had some degree of success with it

I have an HKS metal headgasket, costs bugger all if you can find them.

Nick and Leiden both had stacked factory headgaskets which have also worked fine.

what compression ratio do you have with the hks gasket?

From http://z4.invisionfree.com/lexusaltezzaclu...?showtopic=7121

0.8mm Thick -- 11.5:1 compression -- P/N# 11115-88570 Metal Head Gasket

0.5mm Thick -- 11.9:1 compression
1.1mm Thick -- 11.1:1 compression
1.5mm Thick -- 10.6:1 compression
1.6mm Thick -- 10.5:1 compression
1.8mm Thick -- 10.3:1 compression


The HKS takes it to around 11:1.

so are there any tricks i must know when stacking 2 headgaskets? eg use sealant/dont use sealant, what brand of sealant if its used etc etc. im just trying to find out as much info about it before i deciede wether to buy a a/m headgasket or 2xfactory gaskets.................can you stack 3x factory gaskets to get the compression down even lower? or is that just being silly????

I'm sure you could go three stacked if you want... but would probably be cheaper just to get a thicker one made. I'd personally try to stick to one if you have the chance.

Is there any special reason to lower the compression? won't that give you less response and less power????????

I'm currently having stacked gaskets and seems to work fine...but definately wanting to have only 1 gasket as it makes a big difference after stacking them possibly only for me cause my motor was orginally not putting out any power at all...

The difference in compression that you're changing with headgaskets is bugger all and will make very little difference to power and response.

But in saying that the lower the bigger peace of mind you can have that you're not going to blow your engine up.

If you're tuner is happy with your compression then don't do it.

The ideal way to do it would be low compression forged pistons but that's a few more dollars there.

yea...i've read that from somewhere but on my car it makes a big difference... I've dropped my compression from 10.5:1 to something like 9.5:1 for turbo application....but it makes quite a difference when its 10.5 and 9.5 tho...i get absolutely no power from 0-3700rpm....

9.5:1 is a very nice compression ratio for a turbo.

You might want to look into a ball bearing turbo or something? If it is too much of a hassle you could always just go back to one gasket.

lol...you probably don't know aye...i've blown 1 motor before so think i'm gonna keep 2 gaskets until i get stronger rods and pistons...