Bov?

[Jay-Rock]

i am still kind of a newbie here but i was looking at the forums inthe newbie section and some people said that it will mess up your car if u have a blow off valve that vents into the atmosphere. yet when i go into the parts guide section of this site, it has all kinds of BOV's that vent into the atmosphere. whats the deal? can you or cant you vent a BOV into the atmosphere on a 1G dsm?

 

[Atari007]

read the post "Venting to the Atmosphere?"... that pretty much covers this--

 

[ted_the_mexican]

ok heres the deal with the BOV venting into the atmosphere. The MAF (Mass AirFlow sensor) takes a messurement of the air entering the intake, this includes the air vented by the BOV back into the intake pipe. The computer bases performance numbers like air/fuel ratio on these numbers, so if you remove the vented air you are essentially removing air from the intake. The computer doesn't knwo this though since the MAF is before the BOV vent, so it keeps computing as if it were still there. As a result your engine will run rich due to the changed air/fuel ratio.
In other words dont atmosphere vent the BOV.
Now if you're worried about the dump tube (the little plastic tube stuck right in the middle of the intake) you can simply trim it down. I have done this myself and picked up a slight amount of boost. The BOV sounds slightly different after this mod so don't be alarmed

 

[Atari007]

Originally posted by ted_the_mexican
The MAF (Mass AirFlow sensor) takes a messurement of the air entering the intake, this includes the air vented by the BOV back into the intake pipe. The computer bases performance numbers like air/fuel ratio on these numbers, so if you remove the vented air you are essentially removing air from the intake. The computer doesn't knwo this though since the MAF is before the BOV vent, so it keeps computing as if it were still there. As a result your engine will run rich due to the changed air/fuel ratio.
In other words dont atmosphere vent the BOV.

Just remember, you only run rich when you are shifting gears and the BOV opens... other than that, you should be fine... a lot of people cant tell, and if they do, it isnt enough for them to Stop venting to the atmosphere... if you do have problems, get an air/fuel conroller (like the apexi super-AFC) it will prevent you (from running rich like that)...its a little pricy (about $300), but it is something that you can use (a LOT) later down the road when tuning! hope this helps--

 

[candela]

sorry but the afc wont solve that problem, as leaning it out will effect the motor while your in gear as well. although leaning is an ok way to gain power(sometimes) it can also be dangerous. ill shut up now cause i don't want this to get huge, just read thread that atari said