04scoobsti

installed bov and since then the car idles irregular when warm. dies at stoplights from time to time. it constantly hunts for idle speed between 500 and 1000 rpm. any thoughts? would a hybrid bov make a difference?

dan83590

Its because the BOV is probably a cheap copy. What happens is the springs are set incorrectly, thus releasing presure too early (you probably find it vents on idle, on boost and off boost), the ECU reads this and adds more fuel. The fuel/air mix is now wrong, not good for high powered engines. You will find the car is quicker, more responsive, smoother if you put the OE valve back on.

Dump Valves do not increase power output, single piston and poor quality DV's will actually decrease performance espiecially on turbo'ed car with a Mass Air flow Sensor, ie the subaru.

If a DV is what you want then go for a Baileys Twin Piston type or similar.

Dump Valves do not increase power output, they just make a noise. And if owning a Subaru with that exhaust note is not enough to get you noticed then might I suggest you dye you and your families hair bright red, don't forget the the dog.

silent running

lol you know what to do already - flog it and go back to your standard dump valve. Scoobynet is littered with threads about atmospheric dump valves messing up how the car runs.

04scoobsti

thanks appreciate the help

dan83590

So what you decided to do?

ZEN Performance

If you absolutely must have a BOV, and some people really like them, so why not. I can recommend the Turbosmart ones as being reliable and "compaitble" for most peoples setups. Direct bolt on "v-port" is a cinch to fit and works great with standard intercooler, looks nice too!

Paul

ZEN Performance

I've removed a number of those from cars I've been trying to map, only to have the BOV leaking on part throttle causing rich running and poor response into boost. Sometimes they work fine, often they do not.

dan83590

Nuff said. Didnt know that.