jpr98

Hey guys,

Ive got an Evo 7 just hit 119xxx on the OD, I recently put in a BOV (which may be the cause) and ever since then when It is on 100% atmosphere and i come to a fast stop or gradual after giving the car a bit the idle rev hangs down around 200-300rpm and will sometimes if not caught fast enough will stall the car, when on 100% recirculation it doesnt happen as often but occasionally will still do the same thing, cold starts also will occasionally cause this to happen as well.

Open to any ideas and willing to find and supply any info needed.

Cheers,

evo.matt

iTrader: (3)

The car needs to be tuned if you VTA. Until then you should keep the one that recircs.

jpr98

The stock one actually had a split in it thats why I had to replace it, the one I have put in is a GFB deceptor pro 2 which has the ability to be changed from 100%recirc to 100%VTA and everythign inbetween from the controller in the cabin, would there be a way on the stock ECU that I could tune it to be able to do both or would I need to use and aftermarket ECU and run two different maps?

Evo VI.

VTA valves just aren't ideal at all on evos.
As said stick with a recirc.
The Evo 9 Metal OEM recirc valve is the best one you can use.
Doesn't leak under 1.8bar and doesn't cause compressor surge like other valves that don't leak at high boost.

jpr98

Sorry probably sounds like a bit of a dumb question im still pretty new when it comes to turbo cars, what is compressor surge?

Evo VI.

It's when the turbo is spooling too much air for the car to consume and the air is forced back against the turbo blades causing them to slow or stall as the BOV is so strong it doesn't release much pressure as a soft spring BOV that will leak boost.
It happens at part throttle mostly.
Larger turbos have anti surge housings to prevent it.

sagravtj

It sounds like a duck just swallowed a bottle of beer, and it is trying to cough it out.

jpr98

Cheers

jpr98

Is it possible though to put on two different maps? one VTA and the other recirc?

Evo VI.

VTA is going to cause problems regardless.
I know it sounds cool but it's allowing air to escape that the MAF has calculated and is adding fuel for it, which in turn makes the car run rich and stall.

evo9parts

The only way to correctly run VTA would be running Speed Density (SD). Although, this alone should not be the basis of doing so.

jpr98

ok, cheers

jpr98

so after about a day and a bit of having it run on 100% recirc im still having issues with it randomly stalling twice in a row? both on a bit of an incline from what I can see (doing the bubble test) i cant seem to find any boost leaks. anyone else know what else could be causing this issue?

Evo VI.

IACV is another possible cause.
In your other thread I see you may have a faulty MAF.

jpr98

IACV??

that was changed yesterday lunchtime