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blow off valve

3K views 15 replies 10 participants last post by  Longshot 
#1 ·
i know i know but i couldn't find what i wanted to know, my question is can you recirculate an aftermarket bov like an rfl or something and if so will is still be loud like it is when you dump it to atmosphere, also while i am at it i have read alot about putting a bov on the wrx is a bad thing some things about boost spikes and turbo lag. i would like some more clear answers about that too.
 
#2 ·
The RFL isnt a recirculating BOV. If you want one that does, get a 50/50 hybrid BOV or something similar. There are a few of them out there.

The BOV does nothing positive for your car, besides make noise. The negative effects are debatable, but, no doubt, there are negative effects. Slow spool in between shifts, running rich conditions, and many more. You can definitely find the results on your own, you didnt search hard enough grasshopper. :D
 
#5 ·
i actually got a quicker spool and shifts when i put my rfl on. it did cause a rough idle tho. they will throw the ecu off a bit if you dont get a recirculating b.o.v since the air dosent go back to the turbo like on your stock bypass valve. its not gonna make you any faster, but from my experience it wont hurt anything either.
 
#6 · (Edited)
well i have absolute proof that an atmospheric bov causes a rich condition everytime you shift or rev it up til it vents go here and watch the video http://vids.myspace.com/index.cfm?fuseaction=vids.individual&VideoID=19478542 you will see a puff of smoke right after the bov pops off ( sounds good though)


p.s i only use mine for shows and when i feel like makeing even more noise

leave it stock or get a 50/50 if you need the noise
 
#9 ·
Was he using a wide band to log with?I don't think he was.I saw his data logs.I think he misinterpreted the data.It's 100% fact that a 100% atmosheric bov with cause a rich condition right after the shift when you imediatly go back onto the throttle.It's the nature of the beast.There is a reason people switch to blow-through-MAF setups and that reason is to run an atmoshperic BOV and have the air metered correctly.

http://www.perrinperformance.com/products/show/294/Blow-thru-Boost-Tube?category=3
http://en.wikipedia.org/wiki/Blowoff_valve

A quick google search will pull up an ton of info. bov+rich+maf+sensor
 
#10 ·
-1 to the video or to the fact that we're right

its a simple fact that if the ecu is expecting more air then it raises fuel to keep the afr correct then when it dont get it it creates a rich condition :rolleyes:
 
#11 ·
the ecu does not measure what air is available, it measures what should be available. so when you vent a your BOV the air is already counted for but not there anymore. so the ecu add's fuel because the air is suppose to be there. There are some ways to vent and be ok, one being a bigger maf. Instead of having the ecu know what is suppose to be avaiable air wise, it measures what air is actually there. allowing you to vent your bov to the atmosphere and not cause a rich mixture inbetween shifts or a rough idle. you want a rough idle, cam the thing. do it correctly.
 
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