Someone at a Subaru dealership told me that blow off valves result in engine problems and the engine light turning on...anyone else hear anything about this? Also, what are the benefits of a blow off valve?

 

depends on the vavle.

There is really no benefit in a BOV. It's just sound. Unless you are severly modified and the OEM vavle can no longer hold boost without leaking.

The problem is due to the Mass Air Flow sensor expects that air that the OEM vavle reroutes into the intake system. When the air is not there, the computer reacts badly to it and messes with the fuel mixture and I think the timing as well.

The only neat thing is it will usually make you backfire and or shoot flames, while neat to the spectator, can be bad for the car.

Save yourself the money and get something more important like springs or sway bars or something along those lines.

 

i was running a turboxs rfl bov it was horrible...made the car run extrememly poor I now have a hks ssqv bov...n the car runs a little rich it does backfire sometimes...but yea lovin the sound...but some people say u actually lose some power from the bov...

 

+1

Although I must admit the HKS SSQ was one of my favorites. Plus, it was the only valve that went off without noticable flutter at lower rpms and turned my suby into a flame thrower! lol

AJ.

 

just listen to RedStage, the guy knows what he's talking about......most of the time

 

I have a little story about this. I've got a mildly modded 02 WRX with a turboback and the stock turbo and BOV. A few weeks ago an 04/05 STI pulls up next to me in the entrance lane to a highway. While we are sitting at the light waiting, he proceeds to fire off about ten big fireballs out of his tailpipe, showing off his fancy BOV and catless exhaust. The light turns green, and I gunned it. I made it on to the highway (never breaking the speed limit!) about three car-lengths ahead, even though he was WOT and shifting like a madman, backfiring the entire time. Once we get out on the highway, he's pissed and I let him go by at a highly illegal speed. The last I saw of him was his disgusting, grimy exhaust and blackened rear bumper covered with soot.

Loud, backfiring BOV is equivalent to a giant neon sign proclaiming "I AM A JERK AND I DRIVE LIKE ONE TOO." And as you can see, it isn't a performance mod by any measure.

 

wow...he must not be a good driver...the STI

 

No, he's not a crappy driver, I'm a good one. Besides, I'm running the WHP of a stock 04 STI with my tune; his tune was so bad (greasy black tailpipe, cannon backfires) he might have been running bolt-ons with no pro tune and could have HURT his performance, rather than helped it. Like I said, a full-atmospheric BOV is not a performance upgrade. If he upgraded his turbo to a larger one, he may not be shifting properly to match the new power curve, or he could have had too short of a distance to let the turbo spool properly. The TD04 is a dinky little turbo, but I can be on full boost one heck of a lot faster than a larger turbo.

 

[QUOTE=J blow off valves result in engine problems [/QUOTE]
a BOV will make your car run richer (more gas input). not sure how much damage it would do to your engine. im guessing slight. i have a SARD BOV and no problems yet, but i doubt it is good for your engine.
having a BOV wont turn the engine light on. problems that the BOV might cause like blowing something up or whatever random will cause the engine light to turn on.
the cool sound haha. but performance wise, for your suby, it will only benifit once you start boosting more psi like having a new turbo and such.