#7868, "Atmosphere venting, what does it do?" Oct-08-05 11:55 AM by FlyinEsi
I've been talking to some 1g and 2g guys, all of which are running open vent from their BOV. All of them have idle issues if they rev the car up real high and let it off, but other than that they say their cars run fine...
What are the potential problems with running open atmosphere BOV?
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I've looked for a while to find out what it does...then when I'm not looking, shopping for other parts, I come across this....
Best suited for speed-density or blow through maf systems because it cannot be recalculated back into the intake pipe for use with draw through mass air systems. Use of this bov with a stock maf will cause stumbling, bad or no idle, and hart throttle hesitation. Whenever the bov is venting the car is running way too rich.
#7869, "RE: Atmosphere venting, what does it do?" In response to Reply # 0
I can't believe you even asked this question. This has been gone over MANY, MANY times. A car running a MAF before the BOV measures the amount of air taken into the intake and supplies the correct amount of fuel for the measured amount of air. If you VTA, you are letting out measured air but the ECU is still supplying fuel for the air you just vented. Therefore, you are getting fuel for air that is not there anymore causing you too run extremely rich for a second which in turn will cause your car to stumble.
__________________________________________________________ -Tony <--- NOT asian. '06 Wicked White EVO IX
Originally posted by Avenger When I raise the BS flag ... it's a really big fucking flag and I raise it really fucking high too.
"Never whistle while your pissing." ~The illuminatus Trilogy
#7871, "RE: Atmosphere venting, what does it do?" In response to Reply # 1
Thanks man, I knew the part about running rich for a second, but I was looking for what kind of engine problems I would be looking at, which was crappy idle, and engine hesitation. I even looked in this forum for an answer but couldn't find anything.
I just had to try it though. I went out and just took off the hose to the BOV. The car ran perfectly fine at first with it off, no struggling idle or anything, I went for a drive and I can't believe the sound difference. The N/T guys are lucky for that. But I went about 5 miles, having fun with the throttle, blowing off at 19psi from the Greddy Type S and it sounded awesome. When I came back home though, the rpms were hanging out around 600ish and the car was sometimes struggling to stay running. I hit the throttle to about 4500 rpms and the rpms went back to where they were supposed to go.
I really wish I could install this Tial BOV I have sitting on my floor but I don't want to spend the money for the GM MAF setup just so I can have a louder BOV and have to worry about adjusting the MAF all the time.
I just hope the BOV is louder with the GT35R turbo on with the Greddy Type-R BOV.
#7874, "RE: Atmosphere venting, what does it do?" In response to Reply # 5
Install the buy a 3Bar Map Sensor, buy a GM MAFT setup and then install Tial. I have a spread sheet that will help you calculate all your adjustments. Its not really that heard...I just recently did it for Jimmy's car. You only need to do the adjustment once. You have my phone number, I can help you along the way.
Also, you don't HAVE to adjust the maft. You car will run fine w/o it adjusted. Its all up to what you want.
_____________________________________________ Jerrome B. 1995 GSX - Race 1997 GST - Drive 1995 GST - Who the hell knows
#7876, "RE: Atmosphere venting, what does it do?" In response to Reply # 7
Originally posted by Hult250R
Originally posted by BigBald Install the buy a 3Bar Map Sensor, buy a GM MAFT setup and then install Tial.
Where does the 3 Bar Map sensor come into play?
When you install a GM Maf w/ Translator on any car, it is supposed to emmulate the stock mas. The problem with it is it usually doesn't. On average it can read as much at 14% higher then the stock mas. This will cause you to run crazy rich, meaning that your airflow reading will be extremely high. Now some people can live with that. If you have DSMlink, you do not have to live with that. You can install a map sensor and adjust the airflow reading to be as accurate as possible. Here is an example on Jimmy's car of what i did.
You can see in the Before Picture how far the aifflow reading was off by comparing BoostEst and GM3Bar. The ECU was seeing 10psi higher then we were actually boosting:
Here is the graph after i made my airflow adjustments. The ECU was now reading Airflow alot more accurately then before. This is what the MAp sensore enables you to do via DSMLink. Because of this, everything in the ECU will be alot more accurately.:
I also love the idea of being able to log boost and analyzing the data based on the info provided. And the Boost Gauge and Map Sensor were pretty much the same give or take 1psi. Add a Wideband to the mix and you can tune pretty accurately...Which he also had.
_____________________________________________ Jerrome B. 1995 GSX - Race 1997 GST - Drive 1995 GST - Who the hell knows
#7878, "RE: Atmosphere venting, what does it do?" In response to Reply # 0
Besides stalling when clutch down, bad idle, and funky idle, you'll also trash a good set of plugs, o2 sensors, and who knows what else from running rich. My A/F gauge showed a jump from 14.5 to 10 and then back to 14.5 in about 1 second. Thats where it kills you. Back to stock now, but getting the GM set-up soon.
#7885, "RE: Atmosphere venting, what does it do?" In response to Reply # 16 Oct-11-05 06:53 PM by 420a-Tnthewerks
Originally posted by BigBald let me know when you have everything.
Lol I guess that's kind of the problem though, is that everything? I can probably get everything hooked up when I get it, but yeah, is that everything needed to run a MAP sensor with Link?
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