Hi,
I have an 03 WRX TXS Stage 4 running an unmodified stg 4 map.
Some days I get the boost I should (13psi 1st, 15 psi 2nd 16+ for higher gears).
Some days (like the last few days) I am getting 10-11 psi in all gears...with major knock! The funny thing is some days it goes back to normal (stg 4 boost levels). BTW I am running 94 octane and catless.
I have gone back to the stock BOV and replaced boost hoses (except the hose from the T to my boost guage).
Any ideas what this could be? I'm assuming it is hardware (bad FBC? Denso Iridium Plugs gone? Bad Walboro pump? (The pump has been really noisy of late).
My mecanic didn't seem to know, and he is the service foreman at the local dealership.
Any suggestions (however obvious) are appreciated.
Cheers!

Brian Broz

1. your boost is way low.
2. change the plugs
3. get tuned :)

Well,
As an update, I checked the hoses again...and I'm not sure but it seems the zap strap connecting the boost gauge adaptor (that adapts the vacuum line to an electronic connection) was pinching the vacuum line from the turbo inlet hose.
Once I re-located that zap strap I'm getting 15-16psi in lower gears...
So the problem seems to be fixed for now.
But yes, I need a tune to get rid of knock!
Cheers,


BBroz