sammyh

iTrader: (1)

Went out today and noticed that in 3 to 5th gear if I drive normaly and then put my foot down the boost is peaking at 17 -18 psi! it then drops back to 10 - 13 then peaks at 15, then drops of again.
Spec of the car is MY00 with 4000 miles, full ss system and a Hks ind kit.
Please help as I don't want to blow it up!

GRANT

The reason may be due to the decrease in outside temp
This results in an increase of mass by volume.
Have seen the same thing on my car also MY00, but this does seem a little high if the only mods you have done are exhaust and filter.
If the boost increase is that great the standard ECU should cut boost.
Does it hold full boost if you hold full throttle in 5th over a long road or does it fall off?

Grant

sammyh

iTrader: (1)

Grnat, I think the ECU is cutting the boost as after the boost drops it runs as normal.

ric

...maybe your boost-gauge is reading a little high values.
cut out is at 15.5psi and very well noticeable!
ric

Iain P

Sammy, try adding a chamfer to the leading edge of the wastegate feed restrictor (inside the pipe from turbo outlet to T piece), say 0.5-1mm. This should help reduce overboost. If it still overboosts, make the chamfer a bit larger or drill the hole out in 0.1mm increments until it doesn't overboost. You can buy the drills from any hobby/modelling shop. May be worth making a new restrictor to same dimensions as the standard part for when you want to return the car to standard or you go too far on the hole size. If you play with the overboost restriction in cold conditions, it will be fine for warmer days. Let us know how you get on.

Mac's Power

Hi Sam,

It's probably due to the colder weather.
You are infact hitting the boost limiter. In older cars the boost limiter coming in with "head through the window effect". but the MY00 just does it more gently. It has the effect of the boost pulsing. It hits 1.3 say for example reduces to .8 increases to 1.1 and if all is ok then it will hold if not it will reduce again but quite different to a MY98 for example.

Probably the best way to sort it via the waste gate restrictor
sizes as already mentioned.

Paul.
If you need more info then just post and I'll try to help al I can.

SecretAgentMan

My MY00 GT with some decent breathing mods (Essex soundsystem, and a PX ind. kit), peaks at 16.5 psi, and drops back to 14.5-15.
Dunno how exact my gauge is tho....Autometer - courtesy of mr. Tuckshop.

That's way ooop north here in Sweden (fuggin cold).



/Jerry - Sweden

wrx.co.uk

Sammy, thanks for the wheels got them fitted and they are excellent, thanks again.

No filter included though, did you change your mind?

wrx.co.uk

OOPS, forgot to speak about the boost!

My 95 wrx normaly runs at about .9 bar 13.23psi, in cold weather it peaks at just over 1 bar 15 psi, so I wouldn't worry about it to much. Take a look at the dino tests, from

sammyh

iTrader: (1)

Went to my dealer today was told to book in for an inspection poss 2 -3 hours @ £40 per hour Was told they might not find the prob all
Went home cleaned out the boost solenoid with carb cleaner seems loads better overboosting a tad at 16 now I'll give it another clean and see what happens.

Glad you like them Lee! you should have phoned about the filter because I showed my guys in work what to pack - they obviously paid no attention!

I'll sort it out when I go back - cant get the staff etc.etc

Fullonloon

My STI peaks at 1.5 bar and holds 1.2.
Sometime more in cold weather when in 4th or 5th at about 3500 revs - it's quite noticable as you get a real jolt as it kicks in - but then settles down.
More peak boost recently, could be due to downpipe...but then I don't know much about it.

KPM

SammyH - Sorry if these questions are a bit simple but - What does the boost solenoid look like, where exactly can I find it and how do you clean it?