wrkphil300

my 2005 wrx uk 300 has developed a serious lack of power ! no warning lights on or anything, no strange noises, just doesnt seem to want to pull ! the dumping off through the mushroom filter isnt as loud as it used to be. No smoke out the back and still pulls smoothley ! possibly an air leak ? wastegate actuator ? how do you test if the turbo is boosting full presure ? help !!!!!

ive just been out in it again and the turbo is boosting just not fully ?? any ideas ? acctuator or amal vave ? cheers

joz8968

iTrader: (13)

A boost hose is partially off, I expect.

Check all boost hoses for splits - replace any suspect ones, as necessary. Use fresh jubilee clips if some are past their best. Tighten as hard as you can by hand with a screwdriver. Then switch to a socket set, and turn a further 360 degrees (1 full turn). This should be tight enough for the hoses to remain in situ, and not blow off.

Failing that, then possibly an issue with dump valve leaking. Or wastegate actuator spring broken - or the diaphragm split...???

joz8968

iTrader: (13)

Is it revving past 4500rpm okay?

wrkphil300

yeah mate revs ok, sounds like the turbo is boosting just nowere near what it was ? the car had stood for 3 weeks, then we noticed it ! it still pulls smooth, no misses, it doesnt boost then tail off, it just feels like a constant low boost pressure ? the acctuator when pulled, returns with a bang so i pressume the springs ok ? is the dump valve diaphragm easy to check, do you just remove the 2 bolts from the triangular shaped casting just below the intercooler ? cheers

wrkphil300

also which small pipe would i connect a boost gauge into just to check what psi it is running at ? does anyone know what psi a standard 2005 uk 300 with a ppp pack should be running at ?

joz8968

iTrader: (13)

- Undoing those bolts will just remove the DV form the I.C. Not sure whether the OEM one can be taken apart to check its internals?


- Buy a 3-4mm plastic T-piece and a suitable length of silicone vac pipe to be able to go through the bulkhead for a permanent vac gauge to be mounted. Trace the vac hose that goes to the DV. Cut this vac hose in two, join back together with the in-line ports of the T-piece. Then fit the length of silicone to the remaining 90-deg port of the T-piece and feed through the bulkhead grommet ready for the vac/boost gauge.......

wrkphil300

cheers mate ! found out its the actuator thats faulty so need to replace that do you no what turbo is fitted to my 2005 wrx uk 300 ?

joz8968

iTrader: (13)

Not sure. TD04? VF30? Someone will know for sure - hopefully they'll post up.

Good that you found the problem though - a relatively cheap/easy fix too. I would've said if it wasn't loose boost hoses, then it would almost invariably be something to do with the w/g act.