I just got my car back from the shop and I've noticed that when I go to more than 50% throttle or just accelerating to pass someone in the higher gears (4-6) I seem to be dumping all of the boost or however you want to call it. I can hear the BOV opening up as if I were off the throttle right as it starts to build boost, around 2600 or 2700 rpm and this is only momentary. After it dumps it back into the intake, it keeps on making boost and I do eventually accelerate but it doesn't feel nearly as fast as it should be. Am I just looking at a loose vacuum hose or is it something else? :confused:

Are you sure you're dumping boost? What does your boost gauge do when you're part throttle? If you're steadily cruising at half throttle, as the load on the engine decreases and you accelerate, your boost will decrease somewhat. A stock STi VF39 turbo is barely putting out boost around 2600 rpm (or at least mine doesn't), I don't think that's your BOV you're hearing unless you have an aftermarket BOV that is improperly set up. Also, seeing that you've just got the car back from the shop, do you mind telling us what work you had done? If it involved removing the intercooler, maybe one of your hoses is loose.

when i am in 4th with about 2600-2700 rpm, i am still in vacuum until i hit about the 3k range.

I think I'm around there too, I'm still getting used to the extra wait for the torque peak compared to my wrx that was fully spooled by 2900rpm.

no boost gauge, I had some head work done (valves were bent), so they might have had to remove the IC to get the engine out. As far as an aftermarket BOV is concerned, everything is still stock. No performance mods on my engine yet. All I know is that what I'm hearing sounds exactly like what the BOV sounds like when I let off the gas after accelerating some and building at least some boost. I'm having this checked out by the shop next week anyways, I just figured since it might be something simple like a loose hose I would ask so I can maybe fix it myself. Thanks for the help guys.

whao right there buddy. i wanna know how valves got bent. :furious:

he got in an accident.

how are you guys not building boost till 3000+ rpm.. ?

i guess having some mods makes a big difference in spool

Matt - sounds like the vacuum hose popped off the BPV. That happened to me at MIR - ran a studly 19.7 @ 49mph :)

Check the hose from the BPV and follow it till it connects to something else. It should eventually reach something that provides a manifold pressure reference, but I can't off the top of my head think of where it hooks in.

My car is still stock and I don't make peak boost until ~4100 rpm, I break into positive MAP at around 3K.

serendipity, did you figure out what's going on with your car?


On topic.

Also check the intake pipe for cracks.

Boost doesnt kick in till ~3k rpm for me in my STi

how does an accident bend valves? what else was whack?

If you get into a front end collision, hard enough to knock the timing belt off the cams, you bend valves. Trust me on this one.

jeebus. that sucks.

My car is still stock and I don't make peak boost until ~4100 rpm, I break into positive MAP at around 3K.

serendipity, did you figure out what's going on with your car?


On topic.

Also check the intake pipe for cracks.

UTEC will let you make boost much earlier, and a TBE (or at least a downpipe) will push it even earlier. I was hitting 16psi at about 2800RPM I believe on the stock turbo.

And no, haven't done a compression test yet. I'm pretty sure it's at least one piston.

[QUOTE=serendipity]Matt - sounds like the vacuum hose popped off the BPV. That happened to me at MIR - ran a studly 19.7 @ 49mph :)
QUOTE]

!!!!! How the hell did you get your car to go that fast!! You must have like a $million under the hood!!

[QUOTE=serendipity]Matt - sounds like the vacuum hose popped off the BPV. That happened to me at MIR - ran a studly 19.7 @ 49mph :)
QUOTE]

!!!!! How the hell did you get your car to go that fast!! You must have like a $million under the hood!!

lol. Looked kinda awkward in the middle of all those 12.5s :)