Overboost Problems in my R33 Series II

[The Mafia]

Hi guys.

Fitted a Custom Split Dump pipe, full exhaust, high flow cat

Pod Filter (With bracket and plate to separate from engine bay)

Stainless Steel Turbo Snout

FMIC

and tried 3 different boost controllers.

My Car is overboosting something cronic. When I accellerate hard, the boost will try and hit 15psi+ (and boost cuts, retards, dumps fuel etc)

I have tried 3 different boost controllers, 2 being bleed valves, 1 being a apexi AVC-R.

We took the actuator hose off, and fed it 20psi from and air compressor, and it moved open and shut freely.

The car still overboosts.

Can anyone give me a hint etc on why its doing this?

A mechanic quoted me $500 for an actuator and wastgate for my stock turbo.

Then I have got to add labour onto this!!

[Redbaboon]

Let me get this straight - wastegate actuator has been tested to be okay. I assume that you know you are getting 15psi+ because you have an aftermarket boost gauge.

1. Have you tried a mate's aftermarket boost solenoid? This might be an issue.

2. When you tried the AVC-R, did you fully set it up correctly i.e. aftermarket solenoid and pressure sensor, change hoses ans fittings, disconnect factory solenoid, ECU wiring, etc.?

Don't know if I can be much help, but you can PM me if you want to chat (I am in Townsville).

Good luck,

[The Mafia]

but your missing the point.

With a hose connected from the pressure side of the turbo, directly to the wastegate, it still overboosts, rather than going to 7psi (stock actuator setting)

And yes, I have a brand new aftermarket SplitFire guage.

[rb25]

have you checked when the actuator actually opens? youve fed it 20 psi and the arm moved freely so its obviously open at 20psi, but at what pressure does it actually crack open?

[The Mafia]

have you checked when the actuator actually opens? youve fed it 20 psi and the arm moved freely so its obviously open at 20psi, but at what pressure does it actually crack open?

ok.. The actuator opens fully at 14psi.

This is about right, because it needs a little tension from the exhaust pressure trying to force it open while the engine is producing pressure..

This is how the car is -

0 - 5,000rpm = 9-10psi

5,000 - 5,700rpm = surges to 12-14psi, and boost cuts, dumps fuel, retards timing etc (factory ECU)

5,700 - 7,000rpm car goes back to 10psi, more power again

[The Mafia]

still problems...I am going to burn it soon...Geez its frustrating

[Cake]

i reckon it's your split dump pipe to blame

that it isn't letting the wastegate flow enough

[The Mafia]

i reckon it's your split dump pipe to blame

that it isn't letting the wastegate flow enough

nah its not that, because my split dump pipe is awesome, and flows heaps, and can hold 10psi boost at 7,000.

I spoke to my mechanic and told him my findings. He said the actuator should be creeping open at 5psi.

Mine starts creeping at 14psi.

I thought it might have had extra tension because of engine pressure, but he said no.

[raist60]

Have you actually tried just running the hose straight from intake to the wastegate without having anything at all in it?

I would think that would be the first thing to try if you havent already.

Also you mechanic is wrong, boost pressure PLUS the exhaust pressure are both pushing to open the gate. So the compressor test is kinda void.

[The Mafia]

thats what I thought..

He said it should start creeping open at 5psi.. I am thinking, as soon as the engine creates pressure, its going to blow the wastegate open ... and blow all my boost with it..

This is fcuked, there is no - one in this stupid town that can give me a straight answer.

I hate mackay because its full of "I know it all but are wrong" rednecks.

[Redbaboon]

Talk to a guy named Scott who works at Crawfords Mechanical (Dynolink) Townsville on 4755 0000.

This dude is amazing, a guru. He will know.

[raist60]

Have you tried like i said, with just the line running straight from the intake to the gate?

[The Mafia]

Have you tried like i said, with just the line running straight from the intake to the gate?

With a hose connected from the pressure side of the turbo, directly to the wastegate, it still overboosts, rather than going to 7psi (stock actuator setting)

I am going to get myself a slightly weaker actuator... something that opens at 10 psi, because this one opensat 14psi.

This should effectively drop my Boost by 4 PSI. That way if I wat more, I can use a bleed valve.

I don't know if this is going to solve the problem though.. .COuld create more.

Anyone actually had this problem before?