Stock BPV testing

[mrtheandrew]

After picking up an 07 sport about two weeks ago, i've thrown on a CS SRI/TIP and boost gauge. Although I'm not real familiar with this car yet, it was sounding like the stock BPV was leaking, which was suspected because I would only hear it pop when I was at about 6psi or lower. Anything over that, that familiar woosh would begin before I closed the throttle plate, and no popping when I did. I'm peaking at about 16lbs and holding 13-14 at WOT, which sounds a little low for a stock car with an intake?

I've heard stories of people saying their's leaked, but did anyone actually test it according to the service manual? I pulled mine off and hooked it up to a pump. Its opening around 15 inches of vacuum, which isn't "great" according to the manual, but still within limits. Just wondering if anyone else who claimed their BPV was leaking ACTUALLY tested it or just claimed it was for justification to rice their shit.

[zpele]

[Sacrilicious]

if it's not in spec, you will know it by checking your idle and light throttle LTFTs. if the BPV pops open, your motor will pull fuel ("normal" LTFTs start going down significantly for similar temp/humidity/etc.). all you really need is a DH or AP to check what's important: LTFTs at idle and light throttle, and also WGDC at WOT to see if it maxes.

[mrtheandrew]

thanks. the stock bpv is plenty loud for me... DH is next on the list already. i know its kind of a long shot to see if anyone actually checked their valve for proper operation before changing it 'because it was leaking'.

Originally Posted by zpele

are those 20lb or 50lb sacks? i can't tell.

[Sacrilicious]

Originally Posted by mrtheandrew thanks. the stock bpv is plenty loud for me... DH is next on the list already. i know its kind of a long shot to see if anyone actually checked their valve for proper operation before changing it 'because it was leaking'. are those 20lb or 50lb sacks? i can't tell.

the ones that do check, are just checking their WGDC with the DH/AP. all you need to do (usually) is see if it maxes on like 16-18psi, if it does, you know you're leaking SOMEWHERE...

[mrtheandrew]

I wish I was getting 16-18lbs... I've spiked at 16 once, but usually only hold 13 or so. Maybe its time to invest in a defi as well.

[Sacrilicious]

check your WGDCs, because you need to see if you're only holding 13psi because the car has achieved the load it was targeting, or your BPV is just leaking all over the place.

[karl-hungus]

[TRex]

you are on stock tune right?

stock tune tapers down to 13-14 toward red line...on stock tune you will spike to 15-16 for about 500 rpm then begin to taper off

[Raider]

I tested mine by taking the lid off the trash can and throwing the plastic turd in, and then bolting on a Forge. Blue spring no shims.

[mrtheandrew]

I've lurked long enough to get the understanding that there are no gains to be had from an aftermarket vs a working stock bpv... any reason you switched besides sound?

[Raider]

With a boost gauge, I saw the stock one was leaking boost, so it went in the trash. BPV is not that loud, either.

No gains are correct. But when it boosts to 15 and drops like a rock, yeah trash it.

[MSMS3]

I'm holding 19-20 psi under load with slow taper to 16-17 at 6,000 rpm on the stock bpv at coming up on 60,000 miles with mods below. Most "leaking" valves don't leak. Follow procedure outlined above to test. On stock tune you may not see more than 13-14 psi at 5,500-6,000 rpm depending on barometric pressure, ambient temp, etc.

[phate]

Read up:

http://www.mazdaspeedforum.org/forum/foru...olution-55328/

[drknyte]

Originally Posted by Sacrilicious if it's not in spec, you will know it by checking your idle and light throttle LTFTs. if the BPV pops open, your motor will pull fuel ("normal" LTFTs start going down significantly for similar temp/humidity/etc.). all you really need is a DH or AP to check what's important: LTFTs at idle and light throttle, and also WGDC at WOT to see if it maxes.

What numbers are you looking for, for the WGDC on stock turbo, stock tune?

And how about LTFT's numbers?

Thanks.

[Sacrilicious]

Originally Posted by drknyte What numbers are you looking for, for the WGDC on stock turbo, stock tune? And how about LTFT's numbers? Thanks.

honestly, it's been too damn long since i've run the stock tune to know what it puts out for WGDC numbers. i suspect it won't go anywhere over 70-80% when the going gets tough (4500rpm+)...but that's just a guess...