6G Celicas Forums

I REALLY want to retune my engine.

Currently running an Apexi power FC @ 16.2psi

It's running rich (apparently this is to preserve engine life/make it safer?) and has pretty bad vacuum leak (BOV goes pshhhh for ages after i take foot of the gas)

Massive lag until agout 4500-5000rpm when all hell breaks loose

If it makes any difference engine is bone stock except for Apexi air intake and full 3" HKS Silent Hipower exhaust with custom downpipe. done about 200kms (treated like a queen though)

Running 183kwatw (i thought it was 193, turns out it's not according to last owner)

So what I'm asking (just because I like to know things before I do them), is:

1) how much coin should I allocate for a retune?
2) where do people recommend I get it done? - last place was Torque Performance I believe and to be honest I'm not overly happy with what they achieved
3) What should I consider when tuning and what should I aim for (ie psi and kw) - I heard going beyond 16psi is detrimental to stock internals.

1 + 2 only really apply to other kiwis i guess, but number 3 bring on the info!

If anybody had a few words on the matter that'd be choice, thank you

well since you are in NZ i cant help you much. but there are a few tuners here that can tune via email. basically you do a full 3rd gear pull on the street, datalog everything and email it to them. they will make MAP changes and email it back. just keep doing this untill you are happy. It helps if you are more familiar with your EMS. since you have a PFC, do you have the datalogit box.?

wow didn't understand any of that, but yeah, not really keen on that sort of thing would rather get it dyno tuned.

What i was really after on here was more of a general opinion on what i should aim for given my engine specs/milage. Of course I want a safe tune as it's my daily and i'll be ****ed if it blows up, but i still want it to be quick. Just after a general opinion really

I'm wanting to find a tuning shop too, I don't know anyone in Auckland either and mines not boosting the way I want it to either. I was thinking of going down to Speedtech in Wellington one day and getting it all sorted but in the mean time I don't drive the engine over 5000 rpm (missing out on the best part.)

As for the vac leak I could help you suss that out.

1. Check/tighten the clamp of the rubber throttle body mouth to the IC outlet.

2. Check/tighten the clamps of the turbo outlet/IC inlet joiner.

3. Check/replace cracked/brittle vac hoses from the plenum and throttle body.

I've had troubles getting a tight seal in these locations in the past.
And from past experience, don't buy Supercheap T-bolt clamps, the bolts snap before 100% seal is achieved.

As for the turbo, don't boost it too hard without having the turbocharger inspected and possibly rebuilt. I found this out the hard way when my turbo shat itself 1 week after I bought the car, Toyota noted carboning of oil feed galleries and the turbo due to a lack of maintenance and/or poor quality oil used. The resulting inadequate lubrication lead to bearing failure and everything went wrong all of a sudden, after boosting up a hill in 2nd gear.

So at some stage in that cars life the turbo is going to need to come out, you wont get away with tuning it now, setting and forgetting. From what I've heard from local sources the average lifetime of ceramic ct26 and ct20b turbos is around 150,000 kms so best to freshen it up now before you tune it so it only costs you a bearing and seal set instead of a whole turbine and compressor housing set.

I am trying to figure out why you are running it at 16psi.
Mine is tuned to 12 with capability of going higher but highest I have seen my car go up to was 12.5 and that's when boost gauge began to show me angry middle fingers.

I'm not entirely sure ... 16.2psi is apparently the max you can run on stock internals without risking KABOOMage. Maybe something to do with the US market GT4's being detuned compared to the JDM spec ones. I dunno.

there was no US GT4 (ST205)

if you look carefully hes not from the US he's newzealand.



This post has been edited by Mstoochn: Nov 26, 2009 - 3:01 AM

You've heard 16psi for the engine internals? Sheesh, mines hitting 18+ fuel cut lol.

Some guys here are running jap imported st205 motors and running them at 20psi. As I was saying I think the turbo is first to pack up before the engine. Especially ceramic jap ones.

^^^ This man speaks the truth ^^^

that goes for alot of japanese cars aswell

Well since I'm kiwi. ask around on toyspeed where the group A GT4's get their dyno/tune, If I remember, right when Clint got his TRDGT4 tune, was around the 1000 mark in wellington (though it's properly different). I think since your AWD, your have slightly less of a choice of dynos, since most are 2weels? the 4WD dyno's I know of are in tauranga, and wellington and the one in auckland you went too?

that is true unless perhaps u have a WRC ct20b with a steel wheel. you might see knock before your turbo gives way MAYBE. ask jim, he'll no