i need proof on "BOV"s

**Admiral coFF33** · 27-12-2005, 10:29 PM

Eldar0 what your talking about there is an Atmo BOV not a plumb back, the air dissappears then the fuel lines will inject fuel with hardly any air in there creating a over rich run .01 second

this will hardly affect the 1g/7m engines, that said you will still get a really dirty bum on your supra if its a light colour due to the richness ...

**RobertoX** · 27-12-2005, 10:30 PM

BOV's on AFM powered engines cause all sorts of problems apparantly, it stuffs the readings around royally.

If installed correctly (ie plumbed back between the AFM and turbo inlet) then they shouldn't cause a problem. Has anyone with one installed correctly had trouble with the engine running bad?

**Yian** · 28-12-2005, 12:42 AM

Originally Posted by coFF33

Eldar0 what your talking about there is an Atmo BOV not a plumb back, the air dissappears then the fuel lines will inject fuel with hardly any air in there creating a over rich run .01 second

this will hardly affect the 1g/7m engines, that said you will still get a really dirty bum on your supra if its a light colour due to the richness ...

Atmo venting BOV on 7m can cause some problems apart from the richness. It can get rich to a point that it will almost stall at times.

**ITS-18T** · 28-12-2005, 01:09 AM

Originally Posted by Nim

ITS-18T, is the turbosmart BOV an atmo BOV? As I understand it, the CA18DET has an AFM. With an atmo bov, the ECU will think the engine is still getting full air, and will do some strange things with the injectors, which could be causing your problems with power and boost building back up.
Without a MAP sensor, an atmo bov will make your engine run rich between shifts.

Anyway, you'll notice that most (if not all) newer turbocharged cars come with BOVs. The old ones may not have come with it to reduce cost. The SR20DET does have a blow off valve.

Nim

Yes, the CA18DET runs an AFM. The BOV i was using does vent to the atmosphere.

Now this is where it gets interesting. While running the BOV, i notice the car definately runs rich upon backing off of the throttle, which is evident in the almighty back-fires which the car produces. However, there is also belief amongst some that not running a BOV at all may have a similar effect. In the instance of the throttle being closed, with the air coming out past the compressor housing, back past the AFM and out the air filter, this also affects the AFM which apparently cannot read the direction of air travel. Hence, all this air gushing back out also has a similar effect on the car, with the AFM sensing that more air is coming into the intake than there actually is.

I'd love to try a plum-back system on my car, having the BOV vent back into the intake between the compressor housing and AFM to see what effect this has.

This topic is pretty interesting