Factory BPV - Leaks

[Bravnik]

Just an FYI - This weekend I replaced my factory BPV with a Forge one (Blue with 2 shims). I'm running 19PSI using a TurboSmart with Map Clamp.

Before - With the factory BPV when I was crusing 80MPH in 6th my boost was at like 10-15Vac. Normal Vac at idle was like -26. When I got on it, my boost would shoot up to 19PSI then drop almost instantly to around 16-17PSI.

After - With the Forge when crusing at 80MPH in 6th my boost is at 0 vac/boost. Normal Idle is at -20vac. When I get on it now my boost shoots up to 19PSI and holds steady to 6k.

There is no question in my mind that my factory BPV was leaking like crazy and unable to hold boost past 16PSI very well.

 

[v0ice]

Thanks for showing more definitive proof. I wanted to believe it would be better than the stocker, but no one really had any "proof".

 

[AutoXRacer]

Thanks for showing more definitive proof. I wanted to believe it would be better than the stocker, but no one really had any "proof".

Here is one of my posts on this thread http://www.mazdas247.com/forum/showthread.php?t=123697096&page=4 ; read the red section:

OK, so finally FedEx delivered my SSQV this morning and I slapped it on before the FedEx guy drove away... (lol2)

I bought the expensive one that simply bolts-on. I did not have to buy any other parts, hoses, clips, or adaptors...

I simply removed the stocker, rotated the bypass hose that attaches to the turbo inlet/intake interface so that it matches up to the HKS and then used the supplied hose and adapter to attach the vacuum hose. Oh, I also had to configure the SSQV to recirculation. The instructions come for VTA...I wish...

Oh BTW, I took pictures, I will post them up tonight...

Anyway, fit and finish is A+!!! Easy to install!!!! And 1,000 times better than the stocker...the stocker is really flimsy.

So, what everyone is waiting for...the test drive.

Initial impression is that its quieter than stock!!! (sad)
If you boost anything less than 5 PSI, you won't hear a thing. Between 5-8 PSI and you can clearly hear the flutter. Higher than 8-15 PSI its quieter than stock, I guess that has to do with the valve closing a lot quicker than the stocker. At this point I was a little disappointed...

Engine performance is improved!!! I can't say its amazing, but definitely helps. With the stocker, I held at 15.6 PSI and spiked around 16-17 PSI at 50* degree weather, 30* degree weather occasionally spiked at 19, rarely 20 PSI. Todays temps were 79*-80* degrees. I was piking 20 consistently and held boost at 16.6; got an extra 1 PSI. Now, the biggest advantage I found was that the power between shifting!!! With the stocker, the shifts were smooth and progressive...it eased into boost. Now, as soon as you shift and let go of the clutch and floor it, it threw my head back!!!!

Seems like the engine is very responsive between shifts...I know it has something to do with boost... Maybe the valve closes a lot quicker thus recovering boost quicker...? (huh)

I can't say its worth $275 for its performance gains. It does make a difference, but I would recommend this mod after you've done the basics; intake, DP, TMIC or FMIC, CBE, etc... I think this should be one of your last power mods...unless you have a really bad leaky stocker BPV.

I like it and I'm happy with it. (2thumbs) I wish we could run it VTA though...
I'll post the pics tonight...

The stocker does leak even at stock boost!!!!

 

[aaronc7]

awesome info, I'm at the GFs house on the way to sams...lol. My boost seems to just be spiking now I'm thinking maybe it is the stock bpv.

 

[SuperStretch18]

Mine's a CX-7, but I've found a similar trend. I'm actually back to stock right now for testing and I can't hit higher than about 12 psi. With the forge valve, I can consistently hit max boost, which on the CX-7 is just about 15 psi. The difference is remarkable...

 

[aaronc7]

Yep, my boost is consistently spiking up to as high as 19psi now and quickly dropping back down to 16psi (no boost controller or anything). I wonder if it's the computer doing this or valve...or maybe both? Anyone with intake/TBE/bpv and no boost control?

 

[AutoXRacer]

Yep, my boost is consistently spiking up to as high as 19psi now and quickly dropping back down to 16psi (no boost controller or anything). I wonder if it's the computer doing this or valve...or maybe both? Anyone with intake/TBE/bpv and no boost control?

The MS3 has a factory boost control that control boosts to 15.6 in stock trim...

 

[MS3077]

How to you increase the boost?

 

[AutoXRacer]

How to you increase the boost?

It's factory set...you need tuning to adjust it...piggy back, Cobb AP (if it ever comes out), or a manual boost control/bleeder valve.

Another way to increase boost as a side effect, is to unrestrict the airflow into and out of the engine; intake, TMIC, DP, CBE, etc... Though I only gained 1 PSI, others claim 2-3 PSI.

 

[dparm1984]

So on a stock motor, what benefits does this offer? My car drives well with just the MS CAI (though at times it does feel a tad inconsistent).

If the driveability improves, however, I'm ordering it soon.

 

[AutoXRacer]

So on a stock motor, what benefits does this offer? My car drives well with just the MS CAI (though at times it does feel a tad inconsistent).

If the driveability improves, however, I'm ordering it soon.

Are you asking about the BPV? If your stocker is leaking, then by replacing it, you will have more boost (no more leaking boost) = more power.

 

[dparm1984]

How does one even know if it's leaking then?

 

[v0ice]

Here is one of my posts on this thread

I guess I missed that one! I had only seen unsubstantiated claims...

 

[SuperStretch18]

How does one even know if it's leaking then?

Unless you are tracking with a gauge, dashhawk or something similar, you might never know what you're missing!

 

[AutoXRacer]

How does one even know if it's leaking then?

I didn't know mine was leaking...

After reading how everyone gets 2-3 PSI increase over stock with the mods I have and keeping their boost stock... I started to think I was leaking boost some how...something did not add up.

Though I only gained 1 PSI which is still short 1-2 PSI from other members claims. I felt a difference with the new BPV.

Like I posted in my thread, I don't think this is a priority mod unless your stock BPV is leaking bad and not providing the stock 15.6 PSI boost.

 

[dparm1984]

Yeah after spending $20k on the car I don't exactly have any more money to burn a hole in my pocket, lol. I'll still be reading this thread though.

 

[patty AT forge]

Like I posted in my thread, I don't think this is a priority mod unless your stock BPV is leaking bad and not providing the stock 15.6 PSI boost.

I disagree, boost leaks should be fixed as a matter of course. You might say "its only ~2 psi" but the reality of the situation is that your turbo may be spinning 20,000 rpm faster to reach that boost level.

I would be very interested to see some logs of intake temps before and after replacing the factory installed leak - I mean DV.

 

[Bravnik]

I disagree, boost leaks should be fixed as a matter of course. You might say "its only ~2 psi" but the reality of the situation is that your turbo may be spinning 20,000 rpm faster to reach that boost level.

I would be very interested to see some logs of intake temps before and after replacing the factory installed leak - I mean DV.

Crap, I never thought about that. Bah, I could have logged the BAT before and after if I had thought to do so. Maybe I will do so this weekend. I know I use to hit like 110 or so before and now I think I max out at like 95 while moving. But then again, this is from memory and very well could be wrong.

 

[aaronc7]

What exactly makes a valve leak? Isn't there equal pressure on both 'sides' of the bpv?

 

[hectik1]

Plastic BOVs leak. This has been proven time and time again within the DSM/Evo community. The Evo VIII had plastic BOV....Mitsubishi changed it to a metal BOV with the Evo IX.

AS far as the Mazda...I have a Forge BPV on my wife's CX7. The one biggest difference I noticed was the increased boost response. Upper rpm power felt stronger. Unfortunately I took the boost gauge out before this mod.