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After checking out other topics and posts, I like how the TurboXS BPV clears the TB. I'm confused with what everybody is saying about how there cars run rich when there dumping to atmosphere. Right now I have a 06 TMIC, with the stock WRX BPV vented to atmosphere and the engine is running lean after I let off the throttle.

So....I'm thinking the air going in is being read fine, but then after dumping it to atmosphere the computer has already revived the info on how much fuel should be added, so it should run rich right?

I have a PLX wide band air/fuel gauge that likes to read lean after letting off the throttle.

I did turn the idle up to keep it from stalling at stop lights, and at full throttle the ratio is great! Also at idle it reads fine after start up with out touching the pedal.

I took it to get looked at (a trusted subaru mechanic I know) and he says to get that boost to recirculate!

My question is why am I reading lean when I should be reading rich? And is the turboXS a good alternative? Could the PLX wide band be bad?

Tuck

The rich condition when you let off the throttle after being in boost is a "momentary" rich condition and likely will not be seen on your gauge. It is always lean on decel otherwise when your foot is off the pedal.

A BPV, vs. A BOV (vent to atmosphere) will help you spool up in the next gear and be less of a shock on your turbo.

i have a turbo xs bpv and it works great

As Gteaser pointed out, the gauge is lean under deceleration due to the fuel cut deceleration programming in the ECU. This is normal behavior.

Thanks guys! Im going to order up that BPV.

So I picked up a turboXS BPV and it seems like I need more boost to get it to open right. It works better then the stock by pass valve, but the spring must be rated for 12 psi or somthing. Im pushing 7 psi and it works fine after open throttle.

Part throttle is a different story, as soon as I let off Im getting turbo flutter which I assume is compressor stall. Lastnight coming home from work I messed with the adjustments on the BPV. I unscrewed it to the loose setting and it worked better engaging after part throttle, but still turbo flutter.

Anybody have any ideas of what I should do? I dont plain on turning my boost up till I get the subie dialed in. I was thinking of shortening the spring to reduce tension, but if someday I decide to turn up my boost it probably wont work right.....

I will be buying some hoses/fittings/hose clamps ect. to get it to recirculate back to the intake.
Thanks....

bump

From my understanding, you want a BOV/BPV adjusted as light as possible while still staying closed while you're on the throttle. Lighter spring(s) may be in order.

Yeah for sure man thanks.

i ran mine on stock boost and it worked fine. still usen it with my td04

Tbly89 wrote:Part throttle is a different story, as soon as I let off Im getting turbo flutter which I assume is compressor stall. Lastnight coming home from work I messed with the adjustments on the BPV. I unscrewed it to the loose setting and it worked better engaging after part throttle, but still turbo flutter..

Can you describe what you were doing at part throttle?

I have a TurboXS BPV and I like it. I did notice that with an adjustable BPV it can cause some flutter in low load driving, i.e. between shifts or partial throttle and letting off. Reason is there's not enough boost built up in the charge piping to open the valve. I get the impression that this is normal.

I was assuming that the flutter was compressor surge, but if you guys think thats normal to have turbo flutter at low load that makes me feel better. When I say part throttle, I mean low load (little to no boost between stop lights and shifts). Like you said theres not enough build up to activate the BPV. Its not loud flutter. cj91legss you pretty much answered my question. Im just trying to prevent killing my turbo. I did some youtube surfing on turbo compressor surge and those guys have the flutter sound and it sounds a lot worse on those videos then my flutter.

I could be worrying too much, just wanted to see what you guys have for thoughts about it, and if its normal GREAT! I just dropped 200.00 on this BPV with the adapter. The BPV is pretty kick ass too. Ive already noticed a difference. I feel like the stock WRX BPV that I had on there leaked boost, and as everybody knows it doesnt clear the TB. I wanna get some re-circulation happening, and the turboXS fits the bill.

Thanks for the posts guys!

Sweet! Get it installed and let us know how happy you war with it.

My turbo XS came with a bunch of washers to shim the internal spring. At stock boost levels you should probably have 0 shims in there. I would unscrew the housing and look under the spring.

Under more boost, with no shims, the spring might crack open slightly and not allow full boost...almost like a secondary wastegate on the intake side.

I had to add a few springs because I was running 18lbs for awhile.

So just to be sure, that turbo flutter at low load is fine? If anyone else out there wants to chime in please do.

It never caused me problems. Others should chime in as well.

I ran no bypass or blow off with my FMIC and TD05 at 12psi. It had straight compressor surge. Never had a problem and my turbo is as healthy as can be. And it sounded near, too.

Any journal bearing turbo under 15psi, is not going to suffer from "turbo flutter" or anything else.

Sounds good boys! I got false information.

Thanks!