Help with tuning and Tial wastegate

[zapf]

Hi everyone,
I have run into a problem today when getting my car tuned. Car is a Nissan Skyline R33-25T Stright Six Turbo. Reason I was getting my car tuned was that I have upgraded to a 300ZX AFM from the Skyline one. And installed a smaller exhaust housing for my Garret GT30 turbo. Everything else being the same.

I am running a Tial wastegate.

On the dyno run I loose power when the car reachs around 0.6~0.7 bar boost and anywhere around 4000~5000 rpm. It sounds like its mis-firing and gets all rich with black smoke coming out the tail pipe. So during the day I replaced the plugs, at first we gapped the plugs to .028 then .020 thou without any luck, then we tried replacing the coil packs... no luck. After I got home I borrow from friends car a working "Igniter / Amperifer" that sits on top of the valley cover and tried that in my car without luck. So then I suspect its the Wastegate or the boost control system. Because I can rev the car on the road all the way to redline as long as I keep the boost low.... E.g 0.2~0.3 Bars

FYI - I am running a Apexi PowerFC with the boost control kit. And a Tial wastegate

So I changed boost settings on the PowerFC without any effect to the problem, I then disconnected the blue silcon hose from the boost control valve and it made no difference too. I then tried using another boost control valve from another car that I know its working .... no luck either. So now I suspect its the wastegate that is not working, since I don't have much experience with wastegates can someone tell me what to check for and how? Like procedure of taking it apart if it requires servicing.? Attached is a photo of the setup. Yellow hose goes to pipes after the turbo. And Blue hose goes to the Boost control valve.

Cheers
Felix

[SlowGts-t]

Im not a mechanic er.. but just making a educated guess.

If there is black smoke and the car is missing, the its probably not the wastegate as the car would be just running less boost, drawing less air and therefore putting in less fuel er.. u know what i mean ay? Less boost is sorta like running less throttle. er.. u know what i mean.

Try running the car with the wastegate hose disconnected ( be very careful not to go above your desired boost maximum as the only boost control you have now is your foot) If the car now boost good, then its either your boost controller solenoid or an AIR LEAK.

Air leak, air goes past AFM, ecu says. "ay! I need so much fuel", then air pisses out of leak before reaching engine. and whoops! Too much fuel. un?

Er.. saying that, it could be the AFM (dodgy one)

[Ethan_R33]

yeah zapf, i had those same symptoms.
Tried everything, BUT the air flow meter.
Borrowed a working second hand one off crooser (matt) from SDU forums and it was like a new car!
So maybe try and borrow someones working afm????
Its definitely worth a try mate
Good luck

[[TWUBLE]]

Originally posted by Ethan_R33
yeah zapf, i had those same symptoms.
Tried everything, BUT the air flow meter.
Borrowed a working second hand one off crooser (matt) from SDU forums and it was like a new car!
So maybe try and borrow someones working afm????
Its definitely worth a try mate
Good luck

is a wastegate nescesarry at like 12-13.5psi boost? I was considering buying one. Car is a 92 GTS-t Type M has a 3" exhaust and a K&N pod filter and boosts just under the 7 on the standard boost guage..(which i was told 7=1 bar)

[zapf]

"wastegate hose disconnected" done that. And still happens. I find the problem is dependent on boost and not rpm. It requires about 0.6~0.7 bar boost then it happens. If I slowly bring up the revs to 7k on the road (with load) it would not happen.

Just spend $200 recon to recon the AFM this week. So I tend not to think its that.... I hope....

"wastegate nescesarry at like 12-13.5psi boost" yes.. when you run a turbo like a GT30 which is not internally wastegated then you need a external unit. Any turbo cars requires a wastegate.

Cheers
Zapf

"God HELP me"

[[TWUBLE]]

Originally posted by zapf
"wastegate hose disconnected" done that. And still happens. I find the problem is dependent on boost and not rpm. It requires about 0.6~0.7 bar boost then it happens. If I slowly bring up the revs to 7k on the road (with load) it would not happen.

Just spend $200 recon to recon the AFM this week. So I tend not to think its that.... I hope....

"wastegate nescesarry at like 12-13.5psi boost" yes.. when you run a turbo like a GT30 which is not internally wastegated then you need a external unit. Any turbo cars requires a wastegate.

Cheers
Zapf

"God HELP me"

oh ok... well my car only has a standard BOV, standard turbo and i spose a standard wastegate... should i get an aftermarket wastegate? is there anyway to make the stock wastegate louder?

[SlowGts-t]

Zapf,

Er.. a leaking wastegate should not cause black smoke/missing. It'll just limit the amount of boost you can run, and the car will feel flat, nothing else should happen.

I still say that its the AFM, I mean you havent changed anything else but that. Also. there is a lot more airflow at 0.8 bar and 3000rpm than no boost and 7000rpm.

Er.. also, have you looked for any boost leaks? They also make the car run funny and puff smoke.

SOmeone once told me that the boost cut on an R32 is actually an airflow meter signal cut. Anyone confirm this?

TWUBBLE,
no you dont need an external wastegate witht he factory turbo. Kinda pointless. +7 on the factory boost gauge is actually only 13.5 psi or 0.9 bar. Your car would probably be running about 12psi from the mods you have listed.

Be careful though cos 1 bar isnt much above that as the factory gauge runs out of range. Eg, dont wind up the boost without an aftermarket boost gauge.

[[TWUBLE]]

Originally posted by SlowGts-t
Zapf,

Er.. a leaking wastegate should not cause black smoke/missing. It'll just limit the amount of boost you can run, and the car will feel flat, nothing else should happen.

I still say that its the AFM, I mean you havent changed anything else but that. Also. there is a lot more airflow at 0.8 bar and 3000rpm than no boost and 7000rpm.

Er.. also, have you looked for any boost leaks? They also make the car run funny and puff smoke.

SOmeone once told me that the boost cut on an R32 is actually an airflow meter signal cut. Anyone confirm this?

TWUBBLE,
no you dont need an external wastegate witht he factory turbo. Kinda pointless. +7 on the factory boost gauge is actually only 13.5 psi or 0.9 bar. Your car would probably be running about 12psi from the mods you have listed.

Be careful though cos 1 bar isnt much above that as the factory gauge runs out of range. Eg, dont wind up the boost without an aftermarket boost gauge.

k thanks man!

[zapf]

You are right it a FRIKKEN boost leak. one of the clamps holding the silicon hose is not tight. So up till 0.6~0.7 bar it holds and beyond that it leaks air.... car is all good now. ;o) Yuppy... lets hope the weather comes good.

Zapf

Thanks for all the help ppl.... guess what both Robin and Glen thought its the plugs / coils.. but only took guys at M's 15mins to figure out what the problem was.... ~!!!!

And thanks GodzJr for all the help last night.

Cheers

[GTS-4 Ben]

heeh, yeah one thing to do when crap like that happens.. check all pipes

[SlowGts-t]

Hee hee and Im not even a mechanic

On that subject, boost leaks kill turbos but not engines.