I have a 98 GS300, have added a thicker head gasket, 61 turbo and intercooler. Presently boosting 15 psi, want more. If I add alky, like I have on my Stage II Grand National, how much boost can I safely run without destroying the engine? I can boost 30 psi in the GN.

All inputs and ideas appreciated !!!!!

 

Even with the head gasket, 15psi you are already pushing the limit.. The head gasket lowers compression however the pistons & rods won't be able to handle much more power. Your next move should be to either replace the internals with boost friendly parts or just swap a 2JZ-GTE short block that already has forged pistons and rods. That block can handle 600-700rwhp with no problems. The swap is very straight forward...

Another issue is the tranny. Not sure how much power your putting to the ground, but if you haven't rebuilt the tranny yet, you will soon. The stock tranny can handle about 400rwhp. After that, it just a matter of time before it gets destroyed. What kind of fuel management are you running for your setup?

 

how thick of a headgasket? 2.5mm or 3mm? I'm not too familar with alcohol injection but i would rather build the block to handle the boost if you're going to run higher PSI than you already are.. (not a fan of thicker headgasket)Raising your boost will most likely blow your hg. What octane gas are you currently running.. pump?

You can either Swap in some GTE Internals or just do the whole block like LXOGOOD said.

Tranny will definately need to be built to handle all that power. I will have my stock tranny for sale soon off my 99 GS300 hit me up if you need it.
You can probabaly contact Sound Performance or even boost logic for a tranny build.

I'm also curious of what fuel managment you're using. No point in more upgrades if all you're running is a piggy back.


WELCOME to the forum by the way. Please post up more info and pictures of your setup if possible.

 

Visit www.clubna-t.com that's where Iam researching these days.

 

Thanks to each of you for the input. I will post the upgrades on my car asap. If the GS engine can't take the higher boost, I'll accept that. But my GN originally had cast pistons and rods and it could boost to 25psi. w/alky all day long.

Maybe I'll buy a Supra engine and swap out the original even though it only has 32/k miles. I want to put 600 hp to the wheels. If I can do this with a 19 year old car then maybe technology will enable me to duplicate this in the GS. My trans. has been beefed up to take the abuse.

Look forward to learning from you guys. Thanks for your kindness.

 

I wanna see pics,