import tuner: BOVs lose power

[vr4choke]

according to one of the tech articles in the march 09 issue of import tuner, BOVs actually LOSE POWER. does anyone know anything about this? or have read the article. theyve got some hard facts. cant really argue with numbers

[Stealthee]

How can they lose horsepower?

Better BOV's will hold more pressure before leaking therefor making MORE horsepower.

Import Tuner knows about as much as cars as my Grandma. They still think 3s's are DSM's

[VR43000GT]

^^True story.

Assuming your BOV doesn't leak it can hold more boost as Stealthee said. Generally, a BOV doesn't really add nor decrease power as it is mostly a supporting modification. If you put on a BOV that vents to the atmosphere (an open loop) you can run rich between shifts but that's about it.

[vr4choke]

the argument they were making was actually against open loop as opposed to the recirculating ones. they used an evo as a test car and dyno'd it a couple times with different BOVs. the difference was VERY small and went away under high boost upwrds of like 10psi i think, but it did show small power loss from venting off the excess instead of recirculating

[Stealthee]

Thats called biased media.

If they had performed the test on a car that could run open atmosphere stock then it would have been a different story. If they were using recirculating on the Evo then it would have made more power.

[JeenyusVR4]

Ya pretty much what everyone said is right and just to elaborate running an open atmosphere bov on a MAF (mass air flow) car is different then with a MAP (manifold absolute pressure). On MAF cars that air is calcuted before it enters the manifold and when u release the air from the bov into the air rather than recirculating it you are getting unmetered air. So what happens is the car then has more fuel then air going into the cylinders between shifts causeing it to run rich for a split second, but i cant see the car losing very much power the most ive seen or heard of happening is the car dies when shifting. MAP's meter the air inside the manifold so it wouldnt matter what kind of bov you use.

[vr4choke]

so since 3s's are MAF, you guys are saying it wont lose you any power? cool

[Stealthee]

No, 3s's will lose power.

[JeenyusVR4]

lol no it wont lose power for a MAP cuz the air is metered in the manifold which is before the bov but on MAF the bov is after so the MAF has already calculated the air that should be recirculated and it doesnt see the air getting release with an open bov. It will but only for between shifts and a little after until the air/fuel ratio gets back to normal. Its not gonna be a big loss but it will lose some.

[AutostradaVR4]

the issue of running open on a MAF system is less about the negligable power loss than it is about the running rich aspect...running rich will cause your oil to degrade and get contaminated quicker than usual, which, if let go long enough, can lead to bad things...like a spun bearing.
Now, if you really keep on top of your oil changes, it's probably not a problem...but personally i'd stick with a recirculating setup. They make recirc kits for alot of the most popular BOVs anyways.
Just my

[vr4choke]

ok. BTW i dunno if i have told you this before autostrada, but i love your lights man. looks like an audi

[AutostradaVR4]

Originally Posted by vr4choke

ok. BTW i dunno if i have told you this before autostrada, but i love your lights man. looks like an audi

thanks man
they look even better in person...in pictures it looks kinda...flooded out. I fooled around with the exposure and apeture size but the best i could get was this:

Just doesn't do them justice.

[VR43000GT]

^^Pictures rarely do justice.

You run reciruclating BOV on a 3/S unless you want a louder BOV...plain and simple. I have a Greddy Type S that could be vented to the opne atmosphere but I don't. It sill sounds nice...just not as loud and that is fine by me.

[vr4choke]

sorry to revisit this, but im still a little confused. why would an open-loop BOV run rich between shifts? wouldnt it just run rich for a second or so when the BOV is open? and if it runs rich between shifts, would u always be rich when you were in neutral or had the clutch depressed? help me please!

[JeenyusVR4]

what i meant by between shifts was that when you let off the gas when a load is applied the bov will open so basically between shifts and any other time that you put a load on the car then let off the gas. So pretty much whenever the bov is open is when your gonna run rich.