venting BOV to open air

DRFT_240sx · Sep 21, 2004

hi all , i was wondering for a stock car how can u vent the bov to the atmosphere. my friend has a 4g63 on his eclipse ... he got a hks ssqv but the thing is a lot of people telling him his stock recirculative one if swap in with the after market one will mess up with his car.

how did u guys do it back in kl as i see a lot of people doin it on their engine without aftermarket stand alone computer system thanks

techtic · Sep 21, 2004

i think there should be no problem.

vestax · Sep 21, 2004

Originally posted by DRFT_240sx@Sep 21 2004, 15:05
hi all , i was wondering for a stock car how can u vent the bov to the atmosphere. my friend has a 4g63 on his eclipse ... he got a hks ssqv but the thing is a lot of people telling him his stock recirculative one if swap in with the after market one will mess up with his car.

how did u guys do it back in kl as i see a lot of people doin it on their engine without aftermarket stand alone computer system thanks

well in the states they don't recommend changing blow off that vents out to the atmosphere , u`ll run rich while shifting gears cause its suppose to recirculate the pressure back into the turbine , besides that the ecu has been set to spray more fuel while changing gears cause the excessive boost will be circulated into the turbine , in other terms its not passing tru the airflow sensor , its bypassing the airflow , so in a way the airfuel will calibrate with the uncounted air , manufacturers had set the airfuel in such a way , so by installing a aftermarket blow off , some people face this kind of problems , idling surge cause no pressure in the manifold cause of the open valve . most people in the states use the 1G stock blow off valve which is metal , 2G's & evo's comes with a plastic blow off . so by getting the 1G blow off valve and they crush it so that the bov can hold up higher psi and its still circulates and its damn cheap .

Danny · Sep 21, 2004

vestax, stock vr4200 bov can it be vented back to atmosphere without any problems? I am using a rechipped ecu & evo 3 airflow sensor, fuel regulator and safc to control the a/f ratio.

Joeker · Sep 21, 2004

For Turbo engine with MAF sensors, its best to use vent back bov if performance is inclined more than style.

When an atmospheric BOV releases pressure surge, pressure drops in the intake tract causing a siphoning effect to the turbo's compressor, thus the compressor wheel continues to spool and pulling in air through the air filter.

When tat happens, the MAF sensor will signal the ECU to continue injecting fuel because the MAF sensor is reading flow of air being ingested into the engine but in reality, no air is going in as the throttle valve is fully closed.

Tats why MAF turbo engines with atmospheric bov emit a cloud of black smoke when they shift gears. This is due to the carbonized unburnt fuel pumped out of the engine through the exhaust system

In worst case scenario, the engine stumbles (jerk) and dies flat because of fuel flooding of the ignition.

BLaCkHoWLiNG · Sep 22, 2004

*Hail Joeker!*

Joeker · Sep 22, 2004

Wat is there to hail me for? I don even have half a thousand housepower under my hood. like someone here. :P

Danny · Sep 22, 2004

Thanks joeker for the explanation. Now I know why I can smell so much petrol when I wind down the window. Time to look for a hose to connect back the bov.

DRFT_240sx · Sep 22, 2004

well thanks for the advise all....

i thought HKS SSQV holds shut when the car is idling?

anyway then how the heck did everyone put open vented BOV in cars like evo , vr4 , silvia...without haltech and motec etc etc of course....

thank you

Danny · Sep 22, 2004

what setting? I'm using the safc blue screen. The safc 2 has 2 extra nav points and knock detector thats all.

vestax · Sep 22, 2004

best to get those plumb back blow off , HKS SSQV has the adapter ring to plumb it back to your intake .

mist · Sep 22, 2004

i used to run a APEXi twin chamber (atmo), then a GReddy Type-R that was plumbed back on my old car, current car has a HKS SSQV. Joeker is spot on the money. I would add also, that when choosing a BOV that vents to atmo, there are some types to avoid - those that use a plunger like system. You'll find that you have to keep tightening them up, otherwise the car will stall, but too tight, and you won't be venting any air and causing compressor surge. The APEXi unit is good, valve design, didn't cause any idling problems. Atmo BOV give better response in between gearchanges, not just sound :) But after a day, sian lah, prefer a quiet plumb-back system heheh.

jwrx · Sep 22, 2004

You can get a GFB Stealth FX BOV, its fully adjustable between 100% recirc and 100% vent to atmoshpere

so let say you fit it and there some jerking at 100% vent..just adjust in less untill the jerking goes away

I have been using it for a month now..not bad...much better then the SSQV

Joker,

btw i do hope you know that the waffen SS were one of the cruelest and most sick military units out there...murdering thousands...i dont mean to preach...but its not very nice signature

Zeroed · Sep 22, 2004

Mind if I ask... so does the original bov vent the pressure back to the turbo's intake turbine, allowing it to re-draw the compressed air and run it in circles while the throttle body is closed, instead of drawing air through the air filter (hence avoiding additional fuel injection)? Or where does it vent the air to?

If this is the case, wouldnt the air become very, very hot?

Joeker · Sep 22, 2004

Originally posted by jwrx@Sep 22 2004, 16:14
Joker,

btw i do hope you know that the waffen SS were one of the cruelest and most sick military units out there...murdering thousands...i dont mean to preach...but its not very nice signature

Yes! they were known to have comited genocide.

The murdering by the throusands were atrocities in concentration camps commited by SS camp Komandants.

Unfortunately, such acts have tainted the Waffen SS's reputation

They are one of the toughest fighting unit recognized and respected by the allied forces especially during the twillight years of the 3rd Reich.

Initally, The Waffen SS was the eliter personal guard of the Fuhrer

As such, to be recruited into the Waffen SS was an honour which was initial reserved only for Aryans.

But as the war deteriorated for the Germans, the exclusivity was somewhat laxed and mixed units of Waffens SS was created (Norwegians, Austrians, etc)

Danny · Sep 22, 2004

really had a hard time adjusting the a/f ratio with the stock bov venting to admosphere.. after a few hours finally got it right but not 100% perfect. The evo 3 airflow sensor modified on the vr4 works wonders though... the extra power is very noticable. More wheel spin at 1st, 2nd and 3rd gears...cun! Will post my 2nd dyno soon once I've fixed the hose to vent back to the intake and some minor mods.

AlucarD · Sep 22, 2004

Wahhh, Danny .... wheelie at 1st, 2nd and 3rd Gear .. I almost was fooled just now looking at your so called stock 4G63 :o another sleeper eh??

Hope you find the BOV man...

DRFT_240sx · Sep 23, 2004

oh ok..thanks all

any experience on a 13BT ? hehehe would love some feedback on those engines too

Danny · Sep 23, 2004

ahh hello nice to meet u AlucarD, didn't know u hang out there often with Alex also. No la, slow car only...but quite a worthwhile upgrade to evo3 airflow sensor, for RM200+, considered value for money for an est extra of 20-30hp.

Sent my car to Peter's place today to rout the bov back into the intake but still not finished yet. Hopefully it turns out well tomorrow.

vteckiller · Sep 24, 2004

i am using turbosmart bov la...megasonic...
buang angin whole damansara can hear...
http://www.turbosmart.com.au/images/products/fg-bov-003ms.jpg

Why do you need a Blow-off Valve (BOV)?

To eliminate compressor surge when changing gears. Excessive backpressure is created when the throttle is closed during gear changes or deceleration, causing turbo cavitation. This is detrimental to the life of your turbocharger; however fitting a BOV will substantially improve this problem.
By installing a BOV you will significantly reduce turbo spool up time. You will notice a substantial improvement in response from your turbo between gearshifts. Boost will come on earlier giving an increase in torque at lower RPM.

venting BOV to open air

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