Assistance please
 

Hi all. My question is when I am in the upper rev range an on full boost my external gate tends to make a fluttering sound similar to rev limiter but I am not on the rev limiter. Have 2 ideas but would like some help in tracking down the issue. First is that the plugs or leads may be failing causing a miss. The other is the motor may be pinging and that's what I am hearing. Any assistance will be greatly appreciated.

Failing waste gate / solenoid / whatever it is that holds it shut? Could be opening and closing ever so slightly sounding like a flutter.

Do you have a mechanical boost gauge by any chance?

Too many variables.....

Pray it's not ping that your hearing!!

Are you sure it's not just the gate doing it's job?? I.e regulating the boost pressure

boost levels solid or fluctuating?

Electronic blitz boost controller and gauge. I am praying definitely it's not pinging as I said only seems to happen above 4-4500 rpm after the screamer has already opened. Haven't looked at the boost controller to see if it's solid or fluctuating. Boost is only set to 1.1 bar on a td06 could the spring in the wastegate need upgrading possibly?

Back up.

What year car/

What engine?

What mods?

What ecu?

If the boost is fluctuating that would cause concern as to a failing wastegate?

99 Gc8
Ej25 Sti bottom end
Link G4 ecu
Greddy Td06-20g L2
590cc inj
Walbro pump
Mls head gasket
Arp head stud kit
Fmic etc

Some aftermarket ECU's seemed to have problems with the factory boost solenoids which can cause waste gate flutter. Have seen this with a few Autronic ECU's on rally cars.
Usually a fairly cheap fix to replace with an after market solenoid to solve the issue.

Is there any way to determine its a faulty boost solenoid? The aftermarket solenoids where do you get them from? Is it a simple auto one type part or more of a specialist store?

Grimspeed

do you have an aftermarket turbo intake? Sometimes you can get a flutter through those intakes especially if its a cheap one. Sounds very similar to what I had in my old gc8

possible that your turbo is running out of flow causing the gate to close then open ect.

pay money put it on a dyno.

Yeh I don't mind putting it on the dyno the only problem is the closest dyno is 600km away so was hoping to try sorting it out before gettin to the dyno.
Na no aftermarket intake.
Running a td06-20g at 1.1 bar so it shouldn't be running out

You need to bite the bullet and take it to your tuner.
Pinging sounds like gravel rattling round in a tin can so I doubt it's that.
Could be compressor surge. Is it at WOT? Or more at part throttle?

It only happens at wot about approx 4000 and after the external gate has already opened. Is there any way to identify if it is compressor surge. Boost seems to be solid even during the sound