boost problems in 5th gear

[dvs-b4]

hi all

2003 b4 legacy

jst noticed this the other day when i went to overtake a car. i put my foot down in 5th and was half way past the car when i hit boost cut!!! the car is unmodified no boost tap or any thing just a boost gauge.

i have done this twice now i showed my mate last night and he said it is boost cut. its hapning around 19-20psi

it doesnt do it in any other gear that i have noticed just 5th

any ideas on what it could be? or how to fix it

[99GTB]

Is everything standard? ie exhaust? 19-20psi I would say is a tad higher than factory boost. Was it a cold night?

[Guest boostin]

Sounds like you need to clean all of your vac and boost hoses. There are restrictor pills inside some lines and if they block up they make the engine overboost.

And yes, I do mean ALL of your hoses.

[Guest]

would uec help?

[Guest boostin]

No as it doesn't get fed through all of the vac hoses.

[1994legacyrs]

20 psi sounds very high for stock. Mine is around 15psi with minor modification (I think 15 is around stock?). I'm no expert (far from it in fact), but maybe (just maybe!) there is a CEL code?

[dvs-b4]

thanks for some of the ideas guys. yes it is completly standerd no mods but a K&N air filter and boost gauge um yea it was cold last night but the first time it hapend it was mid day. If it was a blockage wouldnt it be doing it in every gear? not just 5th? whats the best way to clean them all

nd yea in every other gear it boost bout 15-16psi 1 of my mates recons it could be the wastegate or something along those lines or maybe some 1 in japan modified it in sme way that i dont know about.

i dont knw how to cheek CEL codes im new to the hole subaru thing and turbo thing to be honest

[WRXER]

Quite common on subbis to get boost cut on stock setups, can be several things. Although wastegate should indicate in other gears possibly?

I had it on my previous wrx and just chucked on a boost tap to fix it, also replacing the boost solenoid is another option... Pretty much thru process of elimination would be the method, personally I just went with the boost tap and that was that. Although I would recommend EBC if that was the route you went down as the boost tap sucked when it came to adjusting due to changing temps.

[dvs-b4]

yea i thaught about puting in a boost controler and a external wastegate but i dont think my machnical insurace will let me

[Guest boostin]

Seriously, clean your lines. Gen 3's are common for overboost problems. Its the cheapest option by far and relatively easy too. All that gunk that coats the idle speed controller also works its way into the lines.

[dvs-b4]

just an update tried this with a full car load nd went up gradualy and had no problems!!! stoped at 16psi like normal. is it commen for the boost to spike and cut when u jst plant ur foot with an empty car or just 1 passenger??