Thread: 3sgte safe high boost?

hey there guys ive just go a sw20 mr2 with a 3sgte 2nd gen,

what is a safe high psi i can ran?

and What is the factory psi they run?

car has boost tap so i dont know what it should be running at

thanks

IIRC factory is around 10 PSI, have heard of people running just over 1 bar safely but you'd probably want to get someone to confirm. Have a google and see what you end up with

yea i have tryed Google everyone has a different view with is lovely

13-14psi should be fine.
But thats amusing all the rest of your fuel system is in 100% condition, 15 shouldn't kill it for quick runs (such as 0-100kph runs) But you wont want to be boosting that in 5th gear down a long straight for a prolonged period with out having the fueling checked.

If you want to be 100% sure just go down to the local dyno, And get a AFR read out on what ever high boost you want to run.
Aslong as your fueling is safe, and your running 98 with correct factory timing the first thing to let go if anything will be the head gasket.

Fuel cut will be at 13psi if yours is like my mates, You can shift it higher using a POT to modify the signal. Mates one has been running 17psi for little over a year with a bit of extra fuel pressure and after market bosh fuel pump.

The fuel cut can be bypassed by disconnecting the MAP sensor on the rear firewall. It is only used for the boost cut feature and to operate the stock boost gauge which is useless anyway. Airflow calculations for fuelling are performed by the airflow meter.

Safe high boost varies depending on the condition of your fuel/ignition system and engine in general. Mine was still rich at 18psi. Make sure you're running NGK BKR7E plugs. Best bet is to get an AFR check done.

Just bear in mind that just because it's safe doesn't mean it'll last. The stock turbo isn't designed to be running those boost levels for prolonged periods of time. Also the stock intercooler isn't that great so it will heatsoak pretty quickly at higher than stock boost. Headgasket will be fine. Takes a lot more than that to blow it.

thanks for all your help i might just keep it to 10psi

Good idea ^

when i got the car witch was 2 days ago it has a miss at idle found out that there was water on the plugs because the lady washed it. cleaned it out then it idle great. but now once you come on to boost it has a really good miss. car hasnt been driven it about 4 months too. any ideas?

Dizzy cap probably needs a clean. Contacts will have corrosion on them. Pay to check all the leads too while you're at it.

oil in the dizzy cap

Replace dizzy cap and rotor

yea i did and its still there. its really strange it only happens when I'm on boost i could be at the same rpm and not on boost and it sweet as soon as i go on boost it starts missing

Have you checked the condition of the plugs man? They are a common cause of misfires. Check plugs, dizzy cap, rotor, leads and coil. All are issues that cause misfires when the car gets wet

gen2 3sgte can run upto 10psi factory then will fuel cut, in my opinion anything over 12psi on the gen2 turbos has no gain and is just pushing ct26 to its limits you will more than likely snap the turbo shaft. Check your ic clamps and check for any vac leaks, as ionic and sunskreens said check /replace dizzy cap, rotor arm, plugs and leads. My suggestion is to check the ecu for any error codes it maybe throwing, drive the car until it is at operating temp, then locate the diagnostic plug under the bonnet this is on the passengers side strut tower. If you bridge the diagnostic plug pins E1 and TE1 with a paper clip (ensure the key is off when doing this), then hop into the car and turn the ignition to the on position, the check engine light will flash a continuous pattern i.e 0.25 sec. on, 0.25 sec. off, 0.25 sec. on. etc if it flashes in this sequence then there are no error codes, However if there is a code the flashing intervals will change you can PM me a video of the CEL with the diag plug bridged and i can check the codes for you?. My GT4 ST205 gen3 3sgte runs 8psi 1st and 2nd gear then 10psi in 3rd, generally speaking toyota say these (gen3 engines) can run in the region of 10~16.5 psi safely on the factory ecu (depending on determining factors), even speaking i havent run mine past 10psi and engine is bone stock.

Read this if you want to increase the power output of your 2nd Gen 3SGTE.
3S-GTE Power Primer

No 3SGTE runs a "CT20" turbo. That's a tiny little junk turbo found on diesel Toyotas. The Gen3 turbo is commonly referred to as a CT20b but this is a name given to it by enthusiasts and not the actual name given by Toyota. Gen2 3SGTE's have a CT26 attached to them and as long as you have a good intercooler, will keep showing gains closer to 20psi but become less efficient the closer you get.

taken it for a ran after work, so it starts "missing" at 5psi and car shacks, gets realy hard to go any higher then 5psi

Read sunskreens last post again. Might pay to join the MR2 forum. mr2.org.nz or something, I can't remember haven't been on there in years. Google it. Will help with all your questions.

oil in the dizzy cap

Changing the rotor won't fix this, dizzy seal letting oil INTO the dizzy it self i'd say

oil is fixed and missing is fix now it detonates lol, think i just brought a lemon

When is it detonating?
Off boost, on boost?

What fuel are you running? What spark plugs are you running?

its detonating at 5psi on boost, running 98 and have got bkr7e spark plugs

Did you reset the timing back to factory when you put the dizzy back on?.

i didn't pull the hole dizzy out so i didn't. but im going to check the timing on it tomorrow once i put new leads and rota on.

I'd start by putting the ECU in diagnostic mode (plenty of info on doing this on the net) and checking your base timing with an inductive timing light on #1 plug lead.

Edit: Beaten to it