ST185 3S-GTE, running stock, what is most boost I can run?

**Howieau** · 17-01-2006, 06:45 PM

What is the maximum stable amount of boost I can run on my standard stabily GT4 3S-GTE, without spiking, or blowing up my engine?

It currently sits on the standard 7psi, was going to put it on 10psi, but after reading a few threads, some people say it would be ok around 12-13psi.

What does everybody suggest?

This is just for now, on stock setup with boost controller.

Cheers!

**Jorrs** · 17-01-2006, 06:51 PM

max id go is 12

**Jorrs** · 17-01-2006, 06:51 PM

and prob not the engine u would have to worry bout it is the turbo...

**cycleofabuse** · 17-01-2006, 09:12 PM

Originally Posted by Jorrs

and prob not the engine u would have to worry bout it is the turbo...

Yeah, if it's a ceramic turbo rumor has it they can only handle about 15psi max before they start to rip themselves apart. So a few psi under that would be ok. But your lack of mods may restrict it a little like your stock exhaust might mean that you can't hold full boost over 5k rpm.
I'd go 12 max on yours, that's what i run on mine but i have a bunch of mods which help.

**Howieau** · 17-01-2006, 09:55 PM

I have 3" exhaust by the way, would that make it ok for 12?

**1gt48u** · 18-01-2006, 08:36 AM

you'd be best getting a FCD ( fuel cut defender ) first if you want to crank up the boost
standard engine 12psi would be ok - best to check mixtures as you increase
boost, listen for detonation, etc. Get a compression test done as well to see how
healthy your motor is. The major issue with these babies is the head gasket so you dont
want to crank the boost to high and push it past its limits

cheers

**DriftR55** · 18-01-2006, 11:48 AM

If you dont have a fuel cut defender (most common hks unit) then u cant go over 12-13psi and thats safe. If u have a FCD then 14-15psi but nothing over 15psi. I own an mr2 3sgte though and I used to run 15 with fcd. Thats my 2cents

**SilverGhost** · 18-01-2006, 07:44 PM

Yeah i run 8 most of the time, but have a FCD (standard fuel cut for a non grp A is around 11-13 psi i think) and dual stage BC to flick it up to 14 when I want some extra oomph.

Cant say too much about permanently running that much boost, but in my case if I was to run any higher with my present setup boost would fall back to 14 as it approaches redline anyway, so I would say 14 is fine, but doubt you could maintain it as you approach redline without a free flowing exhaust and/or Cat mod.

**davedave** · 19-01-2006, 01:25 PM

I have a JDM mr2 computer on my JDM ST185 motor, and I can verify that fuel cut is bang on 15PSI - my actuator wasn't opening.

The non groupA ecus are only mapped to 13PSI anyways, so after that, they just run full rich. Group A's are to 17PSI if I remember correctly.

I'd just run 12-13PSI and leave the standard boost cut at 15PSI.
.

**Aust162** · 19-01-2006, 03:32 PM

My boost cut is at generally 12psi on my jdm mr2 3sgte. 11-12psi, was never able to get it to 15, maybe its my crappy autometer gauge..

**cycleofabuse** · 19-01-2006, 05:28 PM

Well I thought I was running 12-13psi (spikes to 13) but I just installed a new gauge and it says I'm running 11psi. Which does make more sense since it use to run 11psi on the old gauge with any boost controller and fairly stock exhaust. It was also able to hit 14psi before fuel cut came on. I also found a boost leak when i was installing it. I might crank my boost up a few clicks and see how it goes, but I dare say it'll hit fuel cut soon.