how much boost can i run on my 3sgte

[stevo 27]

how much boost can i push before i gotta get rid of the stock injectors on a 3sgte?
any help would be appreciated

[bmeier]

15 psi is considered "max" you might hit fuel cut before that though.

[stevo 27]

so im technecally good until 15
so 12 should be fine then?

[alloroc]

http://www.jekylhyderacing.com/

http://www.jekylhyderacing.com/storymission.htm

If you can't find enough clues on his web Email Jeff he's a real nice guy and may be able to point you in the right direction.

[CelicaST-162]

10-12 is fine, as long as your car is fine. No leaks, not burning oil, fix any engine problems if theres any, then you're good to go.

[stevo 27]

thanks glad to know yea everythins pretty much new in\on the motor

[hellraiser456]

15 psi???

im pretty sure my buddies mr2 is bone stock except for a boost controller and plug and exhaust and intake...and he runs the ct 26 until it near craps itself...at high boost he is up at like 20 psi..now the ct-26 anything over 14 basically is simply useless...

mind you that said..it is possible he has a upgraded fuel system in it but i can't confirm or deny that as he doesn't really know what has been done to the car other than the obvious stuff like exhaust and intake.

that said a cheap injector upgrade i hear going around for the 3s group is use supra injectors...you can find the for really cheap as supra guys usually upgrade them the moment they hit fuel cut or get a lex afm. as to which ones from what engine i don't know..if i had to guess i would say the 7m...but don't take my word on that.

if you know where to look you can probably find them for 20-40 bucks for all four

[bmeier]

above 15 psi is considered to be unsafe, plus the ct26 can barely hold 15 psi after 5500 rpms...

Also adding larger injectors wont do you any good, the stock fuel system is more than capable upto 275 rwhp

read this very good writeup on 3sgte performance
http://www.mrcontrols.com/primers/power.htm

[bmeier]

stevo 12 is fine although you still might hit fuel cut, there is a simple fix to that problem though its in the primer i just posted above

[stevo 27]

now he said stock boost pressure is 10-11
why am i only running 5-6?
i thought it was stock
is the 3sgte in the mr2 diffrent in some way to the alltrac 3sgte?

[New2Talon]

Im assuming your talking about a 2nd gen 3's?

7-8 is the stock boost pressure, with the ct26 and internal wastegate. If the wg spring was changed out then you could have a higher psi w/o using a boost controller. If your not reaching 7-8 and you are running stock then you have a leak somewhere. check vanuum lines and wg.

There are a few mounting differences, but the engines themselves are the same. 93 mr2 have a different intake manifold. Im not sure if the alltrac is the same and for what year.

[bmeier]

you should be running 7 - 8 psi stock. on hot days though if your intercooler is heat soaked you could see 10... this would be in 3rd or 4th gear though near redline. in fact i am willing to bet you hit 7-8 you have to do a pull in 3rd or 4th gear to hit max boost though...

[stevo 27]

i redlined through all the gear regularly till my turbo seals went
and never saw over 6 psi but could the seals have had somethin to do with that?

[Annoyingrob]

Originally posted by stevo 27
i redlined through all the gear regularly till my turbo seals went
and never saw over 6 psi but could the seals have had somethin to do with that?

If the center housing is coked with oil then yes, it can cause issues like that. I've seen turbos with bad seals where the shaft could barely turn.

....However, it's unlikely. I would take off the intake pipe into the turbo, and spin the turbine. If it spins freely, then that's definitely not your problem.

How does the car run? Does it sputter a little at idle? Does it shoot black smoke out at any time? These would be symptoms of an intake leak.

[New2Talon]

Originally posted by Annoyingrob

...how does the car run? Does it sputter a little at idle? Does it shoot black smoke out at any time? These would be symptoms of an intake leak.

symptoms could also be from running pig rich...

[stevo 27]

no spins freely no shaft play what so ever burns alot of oil never seen i blow black smoke before the turbo went it ran like a champ

i guess now that i have it all apart im gonna check for leaks every were
im gonna replace all the basics

[bmeier]

your boost gauge might also not be very accurate... if everything runs fine after you replace the turbo i wouldn't worry about it.

[Annoyingrob]

Originally posted by New2Talon


symptoms could also be from running pig rich...

Yes, a leak after your AFM will cause it to run rich under boost, which is why I asked

[stevo 27]

just curious what power gains could i see
i have the opertunity to make myself a 3" dp and full exhaust for
preacticly nothin
and will it run fine if i toss the cat?

[91tomstwo]

Everyone says it's not recommended past 15 psi....blah...blah...blah

It all depends on the turbo. (i.e. CFM the the turbo is able to flow at X psi)

Slap a wide band on the thing and turn up until you hit high 11 A/F Ratios.

I'm currently running 16 psi on a Precision SC50 and made 320 WHP last year with no issues what so ever. Is it recommended? probably not, but is turning up the boost on a factory turbo recommened? probably not.

If you want more power, upgrade your fuel system.

It comes down to what YOU think is safe. I think anything under 12:1 AFR is safe. You are you're own judge.