Rumors about leaky stock bovs...

[DSMConvert]

Ok I keep seeing this pop up all over the place(insert astriks here to cover forum name) and yet the only proof I seem to come across is " my boost gauge drops past 4K"....so lets start with the most obvious...more than likely the boost is dropping due to the suck ass exhaust, namely the dp that these cars have...they just can't flow the volume required to sustain 15psi at 5k...if the bov WAS leaking at 15psi then you would without a doubt hit fuel cut due to the extra air you'd be pulling in...even though you're gauge only says 13-15psi your ecu is attempting to compensate by allowing more air to be pulled through the maf, which plays a part in the ecu determining fuel cut...simple maf voltage relationship(i can type out the long explanation if needed for clarification)...anyways to the actual test..

Edit: The above paragraph was edited for clarity.

First off let me say that taking the stock intake off at the turbo is the biggest PITA i've ever had...easily took me 2hrs to take it apart without breaking anything...so I did a basic leak test that I do on all turbo cars...pressurized the system to 16 psi via a regulated air source and covered the bov with soapy water....came up with nada...went on to test both ends of the tanks and the connections to the turbo and the im...still nada....the bov actually didnt leak until I pressed it to 20psi, at which point I started getting a very low hissing sound out the recirc hole...drop rate @ 20psi was 2psi per second..

I'll be following this up with some actual logged runs to verify this under actual running conditions, but at this point I'm very confident that the bov is not the cause of this mysterious leaking some people are getting. Those that think/are getting leaking I'd suggest tightening clamps and the bov mount as this was a huge issue on the MSPs when they first came out.

As far as the 1g dsm bov swap...if you can find one cheap, sure go for it. To be honest I myself would probably feel more comfortable with a metal vs. plastic bov...BUT make sure you do it the correct way. CRUSHING IT IS NOT THE CORRECT WAY, the correct way is to drill and tap is for a secondary vac source. To see how to properly mod the 1g valve goto the link below and click on intake, then scroll down to bov mod...though it should be noted the stock bov for the 1gs will hold 15psi without a problem..my original 92 bov still holds 15psi without an issue over a decade later...

http://www.vfaq.com/index-main.html

And since I know someone is going to attempt to argue with me about crushed vs tapped, all I'm going to say is that I've been racing DSMs longer that most of you have had driver's licenses. So feel free to pm me with your arguement...if I feel you have a merited point I will update the thread accordingly, otherwise there is to be no arguing about it, start another thread for that, this is to help those who were wondering about the stock bov.

 

[chiefmg]

Thanks for the work in testing this. I too have read many threads about this, to be on the safe side I bought an unmolested 1g Mitsu BOV (cheaply) for installation should I need it, but for now I will keep the stock unit. While I am sure the factory tested the plastic unit extensively, it is living in a harsh environment subjected to many heat cycles and I would rather not be stuck waiting for a replacement.

 

[DSMConvert]

Wanted to clarify my stance on the stock bov. I do think its a rather cheap piece with internals that will fail after a few years, but under normal use I doubt it will fail in the first 50K miles/2 yrs. If you have access to a cheap bov upgrade then jump on it, upgrading parts is NEVER a bad idea, BUT don't go out and buy a $250 bov just because someone told you this was garbage.

 

[Killer]

Wanted to clarify my stance on the stock bov. I do think its a rather cheap piece with internals that will fail after a few years, but under normal use I doubt it will fail in the first 50K miles/2 yrs. If you have access to a cheap bov upgrade then jump on it, upgrading parts is NEVER a bad idea, BUT don't go out and buy a $250 bov just because someone told you this was garbage.

Not to mention the aftermarket BOVs give that pfffffft! sound. LOL

 

[Klip]

So to clarify, in reading this and other posts concerning BOV's. For the MS6, Recirc only BOV's are safer/cleaner and less prone to potentially cause problems than VTA Bov's? or the so called Hybrid Bov's on the market currently.
The stock BOV is RECIRC? or VTA? or is it a Hybrid (a little of both)?
VTA Bov's are more likely to cause backfires? (a bad thing for turbo engines)

My reasons for wanting to upgrade from the stock BOV are/were:
1) to address any concerns about a leaky BOV and any pressure drops (to keep the pressure constant and allow the turbo to maintain boost as long as safely possible)
2) To me a metal vs. plastic Bov looks better. (I wanted to dress the engine bay to look better for possibly entering in car shows)
3) I could care less about the sounds, (but I don't want it to backfire either)

Again, I am still learning here, so forgive my noobness......(shrug)

 

[kurfgator]

1.The stock BOV sucks. While this valve may be able to hold boost during a pressure test it could get a little more iffy in the real world. The heat from the compressed air is going to weaken the strength of the plastic. I have also seen two people (on other forums) blow the tops of those POS's. Is it really necessary to spend $250+ on a new one? No. But a 1g DSM is def an upgrade. I have one on my car and love it.

2. It has been shown the MAF is NOT RESPONSIBLE FOR FUEL CUT. One person running the ATP kit with their map clamp achieved 26 psi without fuel cut. I'm not a fan of map clamps because it completely removes a fail safe but it has eliminated fuel cut.

 

[Klip]

Okay from a google search I gather a 1g dsm is the BOV from a 90-94 Eclipse or Eagle talon, Mitsubishi? and these can be bought thru ebay or other sources?
Is it a Recirc only BOV? and how much should I expect to pay for a new one, I dont care to purchase someone else's used BOV is why I ask.

 

[Killer]

S
3) I could care less about the sounds, (but I don't want it to backfire either)

Again, I am still learning here, so forgive my noobness......(shrug)

I was joking...and the saying is "I couldn't care less".(stooges)

 

[70]

The thrid gen RX-7 Turbo had issues with its bypass valve. The MSP had issues with its bypass valve. The reason the MSP had an issue was because it was running the RX-7 part.

See a trend?

 

[DSMConvert]

perhaps I should of clarified, the maf is not the only source the ecu relies on to determine fuel cut but IT DOES INDEED play a role in fuel cut. My fault, I wasn't clear on that point in my original post. If you have a link I'd like to see this post of this ATP setup, I would have a very very hard time believing someone is running 26 psi on a higher flowing cfm turbo without some form of fuel control(which would alter the maf signals). CPE proved that the fuel cut experienced by members was not caused by a maxed maf signal, but look very closely they never said there wasn't a correlation between maf voltage, other inputs, and boost cut. But none the less my post was misleading so I have no problem clarifying my comments. Also I can bet you money that if you did manage to max out the maf signal you surely would either A. hit fuel cut, or B. blow your motor from lean fuel conditions.

DSM bovs - You want the 90-94 version which is on talons, eclipses, and lasers. These are made of metal, unlike the 2g versions. Stock they're good for about 16ish psi, modified they can hold upwards of 25psi. While crushing it will let it hold more boost it is NOT the proper way to do it. Should be able to pick them up on ebay for 20-30 bucks.

 

[ALIEN3T]

there on ebay for like 40 bucks plaus shipping for ones that look in good consition. possibly cheaper also1

 

[sikanimator]

I have also seen two people (on other forums) blow the tops of those POS's.

Haha... same here. One guy was just driving home and POP! Man if I was out in the middle of nowhere I'd be pissed. Anyway as soon as I saw that I replaced mine.