Is it possible for a BOV to flow TOO MUCH air?

I'm running the Forge Type RS Kit recirculating, and some of the time, partial throttle driving is smooth. But a lot of time, especially when gradually decelerating from strong boost, the BOV will vent so hard the car bucks. I know one of their selling points is that the piston and chamber are fairly large at 50mm (I believe) able to flow more volume than typical.

I've tried both springs, both pistons, and settings all over the board. Is it feasible to slow down the action of the BOV by restricting the flow of air triggering the valve? Or is there some other solution?

(BTW, stock turbo, Dynoflash tune, HKS RS intake, complete exhaust with cat-delete...rest is in my registry linked from my signature)

 

I had the same experience with the RS when I had it on my car. I was not able to find a setting where I can to drive it at partial throttle without the car bucking. I got tired of playing with this and just replaced it with an APS dual vent DV. Drivability is so much better with the APS.

 

I had a problem when I had my MBC hooked up using the BOV as a source, and my car would buck really bad like you described even with my APS BOV, I changed the MBC to use the turbo as a source and no more bucking, I hope this helps if you have MBC!

 

Thanks dan, I'll look into that. I hade the guys at TopSpeed (Atlanta) install my Forge UNOS MBC while I was there getting a dyno tune. I would think they have the knowledge to hook it up right, but I'll check behind them.

BTW, explain how you use the BOV as a source for the MBC. Now that I think about it, I don't see how that's possible.

 

Both springs - both pistons ? The RS I sell comes all pre-assembled and works perfectly

 

100% correct

Always route a MBC or EBC off the turbo discharge NOT the BOV line

 

I got the "kit" that comes with 2 pistons...a one-piece and a two-piece. The two-piece piston has a metal upper half (sleeve part) a spring, then a plastic lower half that seals against the opening. I guess the spring is supposed to keep the two halves seperated, but no matter which spring I install, the 2 halves are compressed together so hard once the unit is assembled that they are touching and the spring is not doing anything. I'm just using the one-piece piston as it's recommended for recirculating setups according to the manual.

Mine also shipped with the "hard" spring, and after talking to Luis at Forge, he said they are supposed to ship with the softer spring, and he sent me one of those. They are noticably different, as the harder spring is short and thick metal with a raw metal finish, and the soft spring is taller and thinner metal with a yellow finish.

 

I guess some people use a t-fitting between the blow off valve and intake, I don't know why people said that was the best way to do it!!

 

the forge dv can be setup 2 ways, with either end being the exit. Try both ways, and see which one feels better. I had the same "bucking", but then i set it up the way the stock dv comes, and it felt much better.