I was at a car club meeting a couple nights ago, I just hang out I'm not actually in it yet, but anyways a 98 GS-T pulls up. I was asking him about what he's done to his engine. He tells me he changed the fuel system, port and polish, 18G turbo, and he had a FMIC. So, I asked him what he was running his turbo at and he brags and I quote "...I'm running 24 Pounds "SAFELY", but if I wanted to I could do 30 pounds..." That seemed a little high to me. Is it possible to run 24 PSI safely with those mods? I have an RS so I'm not too familiar with the GS-T engine. Let me know what it takes to boost a GS-T at 24 pounds safely.

P.S. Isn't the stock GS-T only 3 psi, or is it more like 5?

Stock GST's run around 11-12psi, IIRC.

As far as 24psi safely.. Injector upgrades, AFC, aftermarket fuel pump and regulator, possibly a hacked MAS, exhaust, IC pipe kit, and a good FMIC. Free mods too, of course. \

he also might not be running 24psi. it may spike to 24psi and then fall off to 18 or so, depending on his setup.

It's possible--on race gas! His engine won't last on stock internals and pump gas running 24 psi. Anything over 20 psi on pump gas and he'll start detonating, even with upgraded fuel system.

I know people locally running 24psi on 93 octane pump gas safely. It can be done with the correct mods and a very well tuned fuel system.

18G is not efficient at 24psi. The flow will slow down and actually cause you to lose power. That turbo is made to run 18 psi on a 4G63 with 20 psi at most.

16G will fall on its face above 18 psi.

Even a Super 20G loses power above 24 psi. This is dyno proven by a good friend who just had his on the dynojet. He was even running C16 race gas, and could not gain any more power out of that turbo above 24. I think he got it to hold 28 psi, but actually lost power.

i know of this gst guy, running 20-22psi with a big 16g etc.. his car is pretty evil.


Michael 99gs
HRC Stage 2
Stage 3 process begins anyone got a 420a block thats not spun/head for sale?

http://www.dreamwater.net/purplebeast

GS-T = bad mamma jamma. Those engines are tried and proven, you just do a few bolt ons and whalla, crank up the boost and enjoy... and if you got a green, then 24-26psi with stock internals is totally do-able... an 18g i dont really know about though..

wow hehe, the stock turbo sux though haha it rediculous after full boost and it gets to the top end your boost actually starts going down haha I'm scared to see how much boost my turbo can put out i'm sure it's some rediculous amount of boost until my piston shoots through my hood :P The turbo is supposedly good to 500 HP!

The big 16g lives at 22psi. Pulls great and doesn't fall out of boost at all. The 20g is perfect around 24-25psi. The Green is perfect around 28, but I don't think I'll ever be there with my talon.