Are Bov's Safe?

[LatinR33]

I was reading my instructions manual for the stealth fx bov I bought and it has this written on the bottom.

"GFB products are engineered for best performance, however incorrect use or modification of factory systems may cause damage to or reduce the longevity of the engine/drivetrain components. "

Does this mean that a bov if running correctly without the typical symptoms stalling etc can be harmful to my or your cars engine?? just something that popped into my mind. All these people with bov's when it may be bad for the engine.

[paulr33]

the bov or commonly known as recirculation valve was fitted to later model turbocharger cars (earlier models didnt have them, aka vl turbo style) to prevent excessive turbocharger failure and premature wear caused by compressor surge on gearchange.

normally without a blow off valve or recirc value when you back off on the throttle or during gear change the throttle body closes and the pressure has to go somewhere that is built up. it goes back towards to the turbocharger as it has no where else to go and basically gets chopped by the spinning compressor wheel and the blades recieve a fair impact "shunt" by the exessive pressure collision. this can lead to premature turbocharger failre in the bearings and compressor wheel.

another side issue is excessive stalling by an atmosphereic blow off valve, the bov functions as a half recircluation valve, it prevents turbocharger failure by prevent the surge but dumps the pressure to the atmosphere. the engine management system (particulary airflow meter) does not know that the bov is venting to the atmosphere and there expects a certain amount of air present in the system (as its told by airflow meter). however the atmo bov dumps the pressure (and air) and the engine uses the amount of air that has been recorded to work out ign timing and fuel however the amount of air in the system is much much less that what was recorded so it goes into a stall

[paulr33]

so in summary cars with no bov or one that is too tight, aka those with really loud turbo flutter or vl turbo woop woop wooop sound is causing damage to their turbo one way or another, and besides it sucks for quick turbocharger response as the compressor shaft gets slowed down by the backpressure collison

[LatinR33]

Interesting, So with a BOV which vents say 90% back to the plumback and vents say 10% would this be detrimental to the engine or would it be just enough to make the air flow meter happy??

[LatinR33]

I sent an email to brett turner the engineer from GFB and in regard to the stalling he wrote back

"I have come across this problem before, it only seems to affect a handful of

R33's. The problem lies with a super-sensitive airflow meter, What I did determine is that the stalling is related more to the

spring pre-load than the atmosphere venting. I

would suggest softening the spring 2-3 turns by winding the chrome cap

anti-clockwise.

[lingeringsoul]

hmmm...interesting.....might give that a try............

did he say a handful? just about everyone here who owns a R33 has that problem...............I think

[INASNT]

Things have stupid warning these days.

Seen the warnings on chainsaws now??

"Caution do not use on genitals" :lol:

[SKY031]

damn...... if i can't do that, i'm going to be returning that chainsaw i just purchased.

[NickR33]

What!?! how else does one trim their pubes!

[LatinR33]

Yeh thats all he wrote to me. Which was pretty interesting as you say because mostly we hear its the atmo venting but this can be different. I was also interested to know if a bov which seems to be running good if its doing silent damage. He didnt respond to that question hence why i thought i would bring this topic up.

[INASNT]

What!?! how else does one trim their pubes!

<{POST_SNAPBACK}>

your gfriends teeth?

[lordsnipe]

the stalling problem is related is the spring..

the richness problem is due to the venting to atmosphere.

[LatinR33]

so in theory if you vent 10% and keep the remaining air . everything should run smooth right with the spring tuned correctly??

[sproosy]

i had a blitz BOV on my 32 a while ago and i also kept the standard plumb back. Never had a problem with stalling. i think you could get away with running 50/50. try and see how you go - your not gonna hurt the turbo as youre venting the pressure thats built up. The only downside would be - your car may run a little rich and you may get some stalling issues. just adjust the BOV to a setting that seems good for the car and sounds good to you.

[LatinR33]

thanks sproosy

[fEkuaR]

Things have stupid warning these days.

Seen the warnings on chainsaws now??

"Caution do not use on genitals"  :lol:

<{POST_SNAPBACK}>

I found that out the hard way.... lets just say there is nothing hard about it now.

[geno8r]

Can we please just like ban all new threads about BOV's full stop? IF a user starts a thread with the keyword "BOV" in the topic, instant 7 day ban or something like that

[Modena]

Can we please just like ban all new threads about BOV's full stop?  IF a user starts a thread with the keyword "BOV" in the topic, instant 7 day ban or something like that

<{POST_SNAPBACK}>

But without a BOV the turbo is boring

Vrooom PPPPSHTT!

[geno8r]

Owww I've got no problems with BOVs, I've got one myself, I've just got a problem with DAM F'ing BOV threads started EVERY BLOODY WEEK. It's a joke, Nobody uses Search.

[Modena]

What about backfire? My mate has an s15 with GFB BOV and his car backfires often. I know its running rich blah blah but is it bad for the car?

Edited January 23, 2006 by Sir-D