coolboy

as above all working ok, but as you come of throttle the is a distinct whistle sound coming from induction area and coming of boost creates a chatter sound, now i have read about this apparently it is the turbo stalling which isnt good but hao do i stop it i run i baileys dv not standard one, and a vf35 turbo, k&n ind, any ideas or help will be much appreciated,


regards

RoRu

You could try using a softer spring in the dv (if thats possible)so that it opens quicker, allowing the air to vent instead of flowing back through the turbo.

Is it a vta or recirc dv?

coolboy

its a vta and i dont know whether i can change spring it looks like sealed unit. any ideas about the whistleing

RoRu

Have you just fitted the K&N?

coolboy

no its been on 4 years m8

69WRX

Finished fitting mine today, exact same problem as you.
The whistling is the pressurised air blowing back through the turbine blades which then causes the turbo to stall and also make the chattering noise you mentioned.
On my car the previous take off point for the DV was 25mm diameter and is now 38mm.
This I believe is the cause and the fix will be either reducing the take off point back down to 25mm or replacing the DV for one which is possible to adjust.

andy

RoRu

Is it a Hybrid fmic?

coolboy

no not hubrid

coolboy

69 wrx my dump valve is the same as b4 and pipework the same

69WRX

Mine is made by autobahn88 but looks identical to the hybrids i have seen.

69WRX

coolboy.
After I fitted mine the boost pressure increased by 3psi so I turned it back down as I have a manual boost controller.
This could be the cause of your problem.

coolboy

the thing is, is that the whistleing occurs when not on boost i.e when stationary and you rev the engine

coolboy

bttt

coolboy

HELP

Jay m A

iTrader: (2)

I have had a similar problem, look at my thread in pojects.

It is the DV not opening quick enough to release the excess air when coming off throttle.

The reason why it never did it before the FMIC was fitted (all components the same) is because now you will have approx 3 times excess air in the system than before, due to the larger core and extra pipework. The DV can't get rid of it quick enough.

Reducing the 38mm down to 25mm will make it worse, IF you are experiencing compressor stall and blowback. If the car judders as you come off the throttle, it is the excess air pushing back through the turbo and back past the MAF, fooling the ECU.

Jay m A

iTrader: (2)

didn't read this bit, That is either a leak (possibly exhaust, dodgy DV) or you are just hearing the turbo, the change in pipework can affect resonant sounds relative to before.

69WRX

Solved my problem today by simply changing the signal hose to the DV ( thats the small hose to the DV from the inlet manifold )

Had about a 4mm internal diameter silicone hose, changed it to a 8mm and BINGO.

Jay m A
Great thread in projects.
My car has virtualy identical mods to yours, just waiting for Andy F to do remap.