Hi everybody,

I have a Lexus SC300 94 AT with XSPower turbo kit currently uploading 8 psi, I bought 550cc injectors due to I want to carry 18 psi, I know that I should change the head gasket for a thicker one so I bought a 3mm Cometic but I read that one of 1.7mm is enough. With this 3mm gasket I'm going to have any problem?, is going to be too decompressed with the consequent lack of power at low revs?, I’m going to be able to carry more psi?.

 

the information you are looking for is better of found at clubna-t.com a 3mm gasket will lower compression to much to be effective in the lower end. at TT head gasket is normally good enough to get you to ~9.2 to 1 compression ratios

 

I would go with the TT one it will work the best, it is 1.3mm. It will handle 18 psi on pump gas if you have a good tune. with a 3mm you would have to run much more boost to make the same power because you are lowering the compression drastically and changing the squish by a large margin. you do not just loose low end power with losing compression, you loose power all across the board so you have to turn the boost up, which means hotter air and more lag to make the same power. keep all the compression you can safely run and the TT gasket will do the trick.

 

Did you receive the head gasket already? Im sure whoever you bought it from offers different sizes. You should call them up and tell them you accidently got the wrong size abnd would like an exchange. You should also get some money back since thicker hg are usually more $$$.

 

I received it already, I bought it from a guy at eBay, I'm going to sell it at eBay too.

 

I had a 2mm and it was sluggish off boost. Could only imagine how a 3mm would be.
Get ARP head studs. I went with OEM GTE. Happy with it.



2JZGE W/stock pistons with 2.0 mm Cometic Head Gasket gives you a 8.57:1 compression ratio

2JZGE W/stock pistons with 1.6 mm 2JZGTE Head Gasket gives you a 9.2:1 compression ratio

2JZGE W/stock pistons with 0.2 mm Stock Head Gasket gives you a 10:1 compression ratio

 

tt hg all the way bro .. i run 19 psi on pure 93 oct and via aem logs saw zero knock across the rpm band .. its all in the tune and if you are running a standalone to fully control timing..with ems most i would run would be 15-16 psi and then grab your gut everytime you hit full boost and hope your knock sensors are working correctly

 

Stock 2JZGTE Headgasket is 1.3mm. everything else is right, nice reference chart should be in a FAQ or something to prevent all these super thick headgasket purchases.

 

do you know what your timing was under full load/boost?

 

sure do but i cant reveal numbers or maps as my tuner always asks me not to , so sorry bro but i can tell you this its not as crazy as what stock ecu wants to dish out

 

lol lexforlife pls tell Alpha if he is ever in colorado to message me.

 

bumping thread. Can someone confirm that a 2.0mm HG will get you 8.57:1? I thought at 3mm HG gets you that...

 

2.5 and 3mm is not needed all you gonna do is keep blow that gasket.

1.3mm tt does a great job you can boost up to 19 psi on 93 the right setup with a standalone.

 

The NA-T i bought already has a Greddy 2.0mm HG. Just cleaning up the tune and would like to know what my compression ratio is. I'm sure my HG is not the limiting factor... its this POS W58 (and AEM V1) haha

 

If you dont plan on running more than 20 psi you may want to look into changing it out later on.
I think 8.57 is probably close.