Aftermarket BOV - Causes RICHNESS!

[WLD747]

After playing around with my aftermarket Blitz BOV today i come to a conclusion with aftermarket BOV's that i believe that everyone faces.

* When you have the stock bov the car runs better / (LEANER).

* Then as soon as the Blitz BOV was installed LAG!, 2 much fuel (RICH). Slower acceleration but quicker gear changes.

* I believe that have a vent to air causes the ecu to put more fuel into the system and possibly retard the timing.

* More fuel means less economy!!!

What are peoples opinion with this.

[GTR-Ben]

You need to have the air recirculating for the AFM to pick it up.

There are ways round this, but an aftermarket ECU is the best way..

I would keep the stock BOV personally.

[HIPSI]

I bought a GFB stealth FX it vents to atmosphere and recirculates, so it prevents over fueling when changing gears which causes the backfire. Haven't noticed any more lag than usual though.

[Kinks]

how can you have quicker gear changes and lag?

The only time a vent to air BOV should cause richness is during gear changes, because that's when the BOV is supposed to open. If it's open all the time you're on boost the BOV is not tight enough!

[rob77]

It causes the car to run rich because the air isnt being fed back into the air intake like the stock bov used to and stock ecu expect so to compensate it'll run richer (usually get a pop/fart from the exhaust on gear changes) and when slowing down and stopping the car may stall at idle. In all honestly you only need to upgrade your bov if you run a much larger aftermarket turbo and much higher boost and even then I'd probably pick a plumback so it goes back into the air intake instead of venting to the atmosphere but if you want the psssssttttchhhhuuuu sound then go for the atmo bov just remember whats going to happen I know cos I've been there and done that, had an apexi twin chamber bov it annoyed me so much I went back to the stock one and I'm still running it even with the gear listed below.

[Steve]

WLD747, I think you got a farked BOV. If they are not adjusted properly, or maintained properly, yes they will be worse.

I bought mine new and only noticed improvement. Yes it was a little more rich as it didnt plumb back, but no where near what some people report (backfiring etc).

A poor BOV, be it stock or aftermarket, will leak boost and can cause major dramas with idle and AF ratios.

[WLD747]

how can you have quicker gear changes and lag?

The only time a vent to air BOV should cause richness is during gear changes, because that's when the BOV is supposed to open.  If it's open all the time you're on boost the BOV is not tight enough!

The lag im talkiing about is related to the acceleration (over fueling). But you still have quicker gear changes.

Does anyone know how to adjust the SAFC to fix this problem.

Regards

Ak

[TTT]

The lag im talkiing about is related to the acceleration (over fueling). But you still have quicker gear changes.

This makes no sense at all..

how do you have LAG, but quicker gear changes?

are you saying that the bov is helping you SHIFT quicker?

I mean honestly..

Look at ROB77's list of goodies, and running the stock bov still.. why bother changing?

there is a mod you can do to the stock bov that helps it hold boost better too and it's free..

Do a search for "stock bov mod"

[Steve]

Why change BOV? just because someone has a stock BOV, does that mean its 'best' - I think not.

I know alot of people have only had troubles with BOVs, but I have only had good results, no negatives at all. IMHO most of the problems associated with aftermarket BOVs is related to poor adjustment or faulty second hand units.

For everyone who has had a bad experience with a BOV, someone has had good, so why not chase the good, and if you get bad, find out what you are doing wrong, then you can see the difference a properly fitted, adjusted and working BOV makes.

[TTT]

true..

but one bad thing about atmo venting is that it is defectable..

stock doesn't have that prob..

I personally don't see the need for an aftermarket ATMO bov at all.

aside from sound, it does nothing good.

Aftermarket plumback would be usefull, if your stock one was not working or could no longer handle the amount of air it had to dump due to the XXX kw that you are now making...

[ix9]

I have a Blitz BOV, It causes me to run rich on gear changes also. Occasionally there's a footlong flame thrown out the exhaust, and I can make the flames myself by putting my foot down then decelerating.

I only use it for wank-factor, other times I just plug the stock BOV back on again....

For quicker 1/4mi. times I would not recommend an Atmo valve.

[TTT]

flames?

I'm guessing no cat??

[WLD747]

The lag im talkiing about is related to the acceleration (over fueling). But you still have quicker gear changes.

This makes no sense at all..

how do you have LAG, but quicker gear changes?

are you saying that the bov is helping you SHIFT quicker?

I mean honestly..

Look at ROB77's list of goodies, and running the stock bov still.. why bother changing?

there is a mod you can do to the stock bov that helps it hold boost better too and it's free..

Do a search for "stock bov mod"

Well i am saying the bov is helping me shift quicker (quicker gear changes). But the lag im describing is extra fuel in the system due to the bov being a vent to air. Thus slows downs the acceleration / pickup.

so after this test i reckon stock is better. Anyone agree?

[TTT]

I personally agree that the stock bov is better than external venting bov.

PERSONAL OPINION...

but please explain to me how the HELL, does your BOV make you shift gears faster?

it has nothing to do with gearbox,clutch or anything that would make a gear shift quicker...

I think that this is in your head to be honest..

[WLD747]

Anyone tryed running the stock bov and an aftermarket bov together?

[WLD747]

the shift quicker refers to less lag between gear changes

[Steve]

So you are saying it decreases lag between changes (something I noticed myself) but causes the car to bog because of the extra fuel, ie, that momentary overfuelling? If it is over fuelling that much, something is very, very wrong.

[WLD747]

So you are saying it decreases lag between changes (something I noticed myself) but causes the car to bog because of the extra fuel, ie, that momentary overfuelling?  If it is over fuelling that much, something is very, very wrong.

Yeh!, thats what im talking about. Yeh the over fuelling is a problem.

[Lozza150]

the lag would be caused by no recirculated air in the pipe's..... so the turbo has to "spool" more air to create postive boost.

The Blitz BOV's were/are designed to run over 1 bar of boost... so it might not be sealing properly.... i find that my car lack's a little when the Blitz BOV is hooked on... I've tried to work out why....and i cant.

as for overfuelling.... it's hard to say that it does... the bov could cause a little bit of backpressure somehow causing the "pop".... then again it could be the ecu guessing fuel ratio's..... i dont know....

[Steve]

Lozza, I dont think so. A good correctly adjusted BOV reduces lag - period. The better the BOV, the less the lag (between changes) It is alot quicker to repressurise the pipework, than to repressurise the pipework AND spool the turbo up again.

The pop is from fuel being delivered after xxx amount of air was measured by the AFM, but not all the air being there to assist in combustion, and unburnt fuel travelling down the exhaust system. It happened less when I had an aftermarket BOV fitted, and completely dissapeared when I had a power fc fitted.

Just remeber also, if a bov doesnt lift early enough (eg, improperly adjusted/overtensioned),the air that reverts through the turbo can be measured again as it goes out of the AFM the wrong way, causing more fuel again to be delivered to the exhaust - this is one of the tricks to achieving large flames out of your exhaust - not overly good for the turbo though:)

My understanding anyways.