After reading many threads re: bov's vented to atmosphere , I had to try it myself. Disconnecting te bypass valve from the return inlet took less than 5 mins....no rocket science involved. just unblolt and plug.....i used the cap from a medicine bottle to occlude the inlet opening

At start up the motor idled fine no bogs no stall rpm under 1000. I drove out of the drive way and switched to second gear keeping rpms just under 25000 and letting off the accelerator between shifts. Again no notable changes. no bogs no stalls and idle was fine.

However at harder acceleration and shifts at higer rpms ( I shifted at 4500rpm's) there was an obvious change. Shifting under 5000rpms and letting off the accelerator the rpm's would fall just under 600. The motor felt as if it were going to stall. This lasted for about 1.5seconds until the motor corrected it self and returned to normal idle (about 1000-800 rpm's)

I drove with this set up for about 1mile and all the way I was recieving lots of looks from pedestrians and other motorist. when shifting over 3000rpms a VERY audible WWWWOOOOOSSSHHH! escapes from the hood.....very cool! I pulled up on a blue 350z and vented a huge one shifting to 3rd.....In return he gives me a thumbs up and revs........I return home shut down the motor and noticed a rich gassy smell....i guess the motor does run rich when the measured air is not recirculated.....after about an hr of cooling down, i reinstalled the bypass valve to the original inlet.

In summary from my experience venting to atmosphere definately has a cool factor.....there is an obvious bog but the motor corrects its self quickly. If you plan on purchasing an aftermarket bov and venting to atmosphere I strongly recommend using some type of air/fuel controller. By doing so you can corrcect the slight bog...and preventing any future problems due to running rich between shifts....other wise Recirculate the the vented air.....

my 2 cents
-ran

I'll post pics and attempt to post sound clips in the future....

 

On the DSMs, there was a noticable loss of HP by venting to the atmosphere... it made the car run rich and even on the butt dyno you could feel the difference

FYI: Bling/Rice/Loss of power = vented to atmosphere or Performance/Power = recurculated/closed loop BOV

 

I love the sound too of a vented bov (the rice boy inside ).
But i get no performance loss either, so its all gravy.

 

stock bov leaks a whole lto and dont close all the way at idle that why it runnin lean if you look in there or even stick your hand in front of it at idle it blows air out of it cause it never friggin closes if you get a after market valve it will close all the way unless its a greddy they are also made to be recycled dont vent recycle

 

Didn't you get a check engine light from doing that?

 

No Check engine light thank god!.....

 

What are the after affects of this if you were to leave it venting, daily use?

Also, do you have instruction on how to perform this?

 

why would you? i never got a check engine light from venting my 2G DSM

 

I only vented the stock bypass valve for about a mile untill i reintalled it back to the intake. So im not sure what would happen if i did this daily. Iwould imagine that maybe eventually a CEL would trip because the motr would run rich......just a thought...

-ran

 

Common misconception....MItsu's DO NOT have a BOV...they use a CBV. This is why you run rich when venting..the air has already been metered and the ECU adds the fuel for it.

 

CEL came on with Buschur 3" turbo back w/ test-pipe. Imagine that. Where are the 02 sims?

 

Venting to atmosphere is a bad idea. When the intake manifold is under vacuum, the BOV will open. This includes when there is no boost in the intercooler pipes. So at part throttle, the BOV will be open, and instead of blowing air out, the BOV will pull air in. Dirty, unfiltered air. If you are going to do this, at least put a filter on the outlet.