1jz boost issue help!!!

[88cameron88]

Ok so this has got everyone stumped.

rebuilt 1jz. t66 turbo brand new. 38mm wastegate brand new with 15 psi spring. no boost controller

put the turbo on and drive the car untuned.... car boosts to 24 psi in every gear
(yes it has a 15 psi spring in wastegate so thats the first mystery)

the car alleady had a fuel cut defender, i then fitted a SAFC2 controller and got the car tuned yesterday.
the dyno sheet read 24psi. the dyno sheet was done in 4th gear.

i drive the car out of the tuners and the car only boosts to 15 psi in 2nd gear!!!!!!!!!!!!!
WTF IS GOING ON WITH THAT!
Put it in 3rd or 4th and the car boosts to 24 psi...
it was booting to 24psi in 2nd before i took it to get tuned!

The tuner wants nothing to do with it saying his dyno sheet clearly shows it making 24psi but thats in 4th!!

the 3rd mystery is i took the vacuum line off the wastegate so it wouldnt open, just to see what boost it would make.. still only 15 psi in second..
then get this.. in 3rd gear the wastegate opens at 24psi!!!! how is it doing this with no vacuum line going to it?!??!

so to summarise, why wont my car mke more then 15psi in 2nd now that its tuned??!!?

[1JZ-Rolla]

Firstly, what brand wastegate do you have?

[88cameron88]

brand new ebay wastegate. also have a new otomoto wastegate. ive tried both and the problem is the same. the wastegate is not leaking or opening. even when it sits at 15psi in 2nd, the wastegate is not opening

[1JZ-Rolla]

I think you just found your problem Can end up chasing your tail with 2nd quality gates mate....... and what they market them at is not necessarily the case. I've tested two HKS 'copy' gates, advertised as having 10psi & 14psi springs, and it took 24-28psi to start the valve lifting during a static pressure test.

What does the boost plot look like when logged on the dyno in 2nd gear? does the boost climb straight to 15psi and then stay there solid? Or build gradually through the revs to a peak of 15psi? If its the latter, then your turbo simply appears to not have the exhaust flow required to spool that turbo setup in lower gears.

At what revs do you reach your peak boost (24psi) in 4th gear?

put the turbo on and drive the car untuned.... car boosts to 24 psi in every gear

BTW: Why would you do this???

[88cameron88]

wastegate is not the issue.... the wastegate is NOT opening in 2nd gear when it sits on 15 pound...
car held 24psi absolutely fine in 2nd gear for a week before i gave the car to the tuner.
im convinced now its in the tune, hopefully going to another tuner later thisafternoon down the coast.

[88cameron88]

oh and i drove it around untuned for a week while i was waiting to get in to a tuner. it was running rich due to bigger injectors and not detonating so it wasnt an issue to drive it. it is a jz afterall lol

[1JZ-Rolla]

wastegate is not the issue.... the wastegate is NOT opening in 2nd gear when it sits on 15 pound...

And why would it open anyway if its got a 24psi spring? I think you might be missing the point...... and don't really seem to have the logged data to determine what is actually happening anyway.


/unsubscribe

[88cameron88]

you seem to think its opening by blaming the wastegate! the issue only started after it was tuned. i dont have the logged data because the tuner was reluctant to even give me a print out of the afrs in 4th gear!

and do you think if i had that data id be on here asking questions? no id have solved the problem!

i asked for ideas not for a smartarse.

[Kedderz]

This tuna sounds like he knows what he talking about, definately take what he says as gospel.

[LeaThaL]

sounds like your car was tuned in some back alleyway somewhere, the tuner we deal with will do 4 pages of laminated sheets detailing every temp and level of everything while it was being tuned and happlly print out copys when needed so maybe it is wise to get another tune down with a larger workshop.

and also anything ebay for performance you have to take their ablilitys with a grain of salt as their always wrong...

[Gttwinturbomk3]

sounds like your car was tuned in some back alleyway somewhere, the tuner we deal with will do 4 pages of laminated sheets detailing every temp and level of everything while it was being tuned and happlly print out copys when needed so maybe it is wise to get another tune down with a larger workshop.

and also anything ebay for performance you have to take their ablilitys with a grain of salt as their always wrong...

Yep i second this advise and also the previous advise from 1jz rolla and i dont think he was intentionally trying to be a smart arse either. Your tuner is not very helpful with it and most likely you will need to control your boost with a electronic solenoid at the very least and if you are running that boost your wastegate is way to small it should be 44mm minimum for anything over 20psi really. Also i hope you didnt push 24psi on pump gas that is a big risk to your engine if you or your tuner did that.

Quote....then get this.. in 3rd gear the wastegate opens at 24psi!!!! how is it doing this with no vacuum line going to it?!??!

In short terms the boost is spiking in a uncontrolled manner and causing it to overboost under higher load with the turbo's higher exhaust gases in 3rd 4th gears this is because of no secondary boost controller or proper control you have to remember your wastegates main purpose isnt to control boost but to get rid of unnecessary gases as quickly as possible. It's only meant to work along with the correct amount of controlled boost that is through a electronic boost controller. Have you got proper electronic boost control or even a bleed tap at 15 psi will work.

[88cameron88]

the car was NOT running a boost controller

the tuner was one of the most reputable places in newcastle, PBE DYNOTECH. i will not be going back there, i asked them not to even touch my car till the tuner rang me and they tuned the car without my permission to go ahead, then they wouldnt let me talk to the tuner on the phone after the car was finished and i complained that they did my car before phoning me i was told to "f*#k off you queer cu#t

so i went to another tuner yesterday.
on 24 psi the car made 413rwhp.. 308kw.
this is on pump fuel. really happy AFR'S.
And no knock.

there is absolutely nothing wrong with the wastegates. we did detect a new slight exhaust leak at the join where the gate goes onto the manifold and we think this is the reason the car is only boosting to 15psi in 1st and second, the turbo is big and needs every bit of gas and load it can to spool up and with minimal load the exhaust leak is making it impossible.
mind you if i have two passengers in the car. making boost to 24 psi in 1st and second is not a problem at all due to the increased load.

[Indelible]

lol so you think its a problem its not hitting 24 psi in lower gears but has a 15psi spring?
sounds like you have no controll over boost at all. so either manifold needs a better merge towards the wastegate or a larger gate

[88cameron88]

it was hitting 24 psi fine in 1st and second before i gave it to the first tuner. read all of my first post. anyway looks like ive found the source of the problem now anyway

[Indelible]

why assume i didnt read all your post i was refering to something you even mentioned in first post

(yes it has a 15 psi spring in wastegate so thats the first mystery)

i understand your wondering what changed since the tuner , but i was just saying the setup cant be optimal if hitting 24psi on a 15psi wastegate spring and should probably be looked into also