Is a retune needed for changing BOV

[BMWM3]

Why is a retune needed when going from a stock bov on a procharger to a tial open version, since I'm not moving the location and it's already blow through why do I need a retune? Was just curious bc my tuner said I should get the car retuned after installing it on my P1sc high output kit? What is the escape of more air changing?

 

[Swarzkopf]

I'm with you. I couldn't imagine needing a retune - if you're seeing more/less boost, since your setup is blow through the MAF should adjust fueling for you based on how much air is actually passing.

 

[TexasBlownV8]

If the discharge of air is significantly different during idle and part throttle, the amount of air entering the engine can be different. Is it enough to require a retune? Depends how much more air is not going into the engine.

Sure the MAF will only measure what is going in, and there should be minimal differences since it is blow-through.

 

[702GT]

You dont. Blow thru the bov should be before the MAF. If you somehow make more psi or increase cfm from the blower by changing blow off valves, it would only reasonably be cause from the prior bov leaking boost and the new one is sealed tight. Just pay attention during a WOT pull, if you see 2-3psi more than normal then you might want to adjust your tune. If a tuner has you tuned to such a ragged edge (unless you asked for it) that a couple extra psi hurts your motor, I'd find a new tuner.

 

[Sky Render]

How close is your BOV to the MAF sensor?

 

[foxxxtman]

LOL, +1 for 2 great signatures there Sky Render and 702GT, both of them made me chuckle. I also can't imagine why you would need a retune on a blow-through set-up.

 

[Viperrmk]

I'm interested in this as well. Been thinking about changing my BOV from the crappy procharger one to a Tial.

 

[foxxxtman]

I can see if you weren't blow-through and you were pushing air back into the airbox but it seems like in your current set-up it wouldn't change a thing.

 

[JeremyH]

Nope.