Dramas with VF34 on 2.5L - Perth-WRX.com

BXT · #1 24-12-2006, 10:51 PM

REMOVED

Intra · #2 25-12-2006, 02:08 AM

I would be very very very cautious with a VF34 on a forrestor, they are of a different compression ratio and also have different timing (more savage then a STI) and there's a reason why they run 8psi...

Have some form of engine management on the car and listen for DET..

BXT · #3 26-12-2006, 12:37 AM

Sorry prolly should have listed the rest of the mods....just thought they were normal when at this stage of mods:

06 XT Forester
BOMZ CAI
Silicone turbo inlet
TurboXS Big TMIC
TurboXS Y-pipe
TurboXS Full plumb back BOV
IHI VF34
Xforce TBE with Single tip Oval Muffler
Xforce Dump & Heat shield HPC coated
Walbro Fuel pump
Xede Piggyback Processor
MAC 3 port boost solinoid

BTW stock boost was around 11psi standard and compression is 8.4:1 which is way below that of an 06 WRX which is 9.0:1.
Car was on a proper Dyno Dynamics 4WD dyno at the time with a very competent tuner.

Any thoughts or experiences out there re. my first post?

Cheers

tuna · #4 26-12-2006, 08:53 AM

the only ever root cause of overboosting is the wastegate not regulating exhaust properly.

this is either the wastegate isnt opening from insufficent pressure, or its mechanically unable to opened due to interference.

have you checked the actuator diaphram is actually seeing the 18-19psi you claim?

BXT · #5 26-12-2006, 11:13 AM

Quote:

Originally Posted by tuna

the only ever root cause of overboosting is the wastegate not regulating exhaust properly.

this is either the wastegate isnt opening from insufficent pressure, or its mechanically unable to opened due to interference.

have you checked the actuator diaphram is actually seeing the 18-19psi you claim?

Wastegate is opening at 9.5psi...this was checked with a proper tool.
Did somemore reading on boost creep and I'm pretty sure that's the problem as we had the wasegate held fully open during a run and it still hit 18.5psi so its a case of the wastegate not bleeding off enough exhaust gases.

tuna · #6 26-12-2006, 11:16 AM

Quote:

Originally Posted by BXT

Wastegate is opening at 9.5psi...this was checked with a proper tool.
Did somemore reading on boost creep and I'm pretty sure that's the problem as we had the wasegate held fully open during a run and it still hit 18.5psi so its a case of the wastegate not bleeding off enough exhaust gases.

i dont think so, that wastegate isnt opening, or your reading 18 psi funny.

got a boost curve printout?

BXT · #7 27-12-2006, 03:01 PM

I've scanned my dyno readout but can't put it up as it's too big...i've resized it but still to big..any smaller and you won't be able to see it clearly....how else can I post it mate?

Elrico · #8 27-12-2006, 03:02 PM

Umm go to google and google imageshack or sumthing.

They are photo hosting websites that are free. Then u just post the URL (address) here and people click on it and walla!

BXT · #9 27-12-2006, 03:02 PM

Here's the best I can do.