V2 sti wrx boost problems

[rowingryan]

Hi guys I've had this problem for a couple of years now & havn't been able to figure it out. It drops boost at 4000rpm to 10psi & feels realy flat & sounds like it has a masive boost leak but i can't find one. If Im doing 80k in 5th gear & floor it it will boost 14-15psi & hold it till 4000rpm. I've been told to check the map sensor & pressure exchange solenoid. Anyone else had a similar problem?

[Stoffa]

coils or plugs?

[rowingryan]

Have changed coils & fitted new iridium plugs at the time of rebuild 20k ago. it had this problem before i rebuilt it. also changed the turbo to a vf23 with no change.

[madmike]

Dirty cat converter restricting exhaust?

[Guest DUSWLO]

any pics of your current engine bay setup?

could be a number of things really.who rebuilt it,have you made sure all vacum lines are were they are supose to be.?

[madmike]

 DUSWLO said:

any pics of your current engine bay setup?

could be a number of things really.who rebuilt it,have you made sure all vacum lines are were they are supose to be.?

Why does it have to have been rebuilt?

[Guest DUSWLO]

i just meant if it was done as a home job.anything could be round the rong way.theres alot of vacume and fuel lines,could have easyly got mixed up.

[madmike]

1. Where did the OP say here that the motor problem had been happening since it was rebuilt?

2. Spell check much?

[madmike]

I Don't really care what device your surfing on. Txt speak and incorrect spelling are just a sign of reduced IQ or lazyness

Back to OP

You describe the car as having a noise that goes with the reduced boost produced.

Normally that leads itself to only being a few things.

1 split hose somewhere that is opening up under/ sustained higher boost.

2 restriction in either the intake or the exhaust.

3 dead turbo ( you have replaced this right?)

4 gasket blown out on intake mani.

Your going to need to go through this piece by piece and eliminate each one by one.

[Johnnynz]

Lol bad spelling infuriates the young as well.

Its kind of like listening to a back woods hick speak, slightly amusing but after a while it just pisses you off.

HAYUK!!!!

Anyway - On topic

Did the issue come with the rebuild or after? If it came with the rebuild sounds like something was put back wrong. If after Mikes suggestions are your best bets.

[Stoffa]

boost cut?? have you got anything other than a factory boost control set up?

maybe wastegate actuator bung?

[rowingryan]

It started doing this before the rebuild (Thats why i decided to rebuild it). It was a intermittent problem at first. I've had it on the computer at work (Wadsco Motor World) & found no problems what so ever. I had the shortblock assembled at a shop & the heads checked over at the same place. Did the rest myself. I also wired the wastgate shut with no change.( would just hit boostcut & then do the same thing again.)

At the time of the rebuild I replaced all the gaskets & seals, checked the boost lines etc.

The exhaust is 3inch from the turbo back with a siamese pipe for the wastegate. Doesn't seem to be blocked.

If I pressurize the inlet manifold on the car i get air coming back out the idle control valve but thats at 110psi.

Will try a few things & see how it goes. Any more ideas throw them at me! Getting beat by my mates s14 turbo at the drags was shameful!!