I just recently installed Buschur Racing's Dual-stage MBC on my 04 RS. Due to its suggested mounting place on the passenger-side strut tower I had to reroute the vacuum lines. I previously had an older style BR mbc mounted under the air filter and tee'd into the same vacuum line as the BOV . A similar arrangement to many other Evo's I've seen. Rather than extend the line around to the passenger side I decided to use the large barb in the center of my intake manifold that was capped off by Dan Buschur during my AEM EMS install last year.

That left the BOV on its own line on the right(driver's} side of the intake, the mbc off the center barb and the fpr on its own line on the left. The installation went perfect and I was able to set the boost levels accurately on a local dyno. I am very pleased with the mbc's performance but I didn't realize it was going to get rid of the annoying part-throttle BOV flutter that I've experienced with every aftermarket BOV I've ever used.

I currently run a Tial BOV. Previously I would experience the infernally aggravating flutter when trying to drive the car normally in city driving. I could only avoid it with crisp shifts and by lifting my foot from the gas pedal rapidly. Now. with its own dedicated vacuum line the flutter is almost completely gone! The car sounds great and is running like the proverbial bat outta hell!

I'm sure this is probably old hat and I just missed this fix all the other times its been suggested. I just had to share the one time The Law of Unintended Consequences worked out in my favor!

 

picture?

 

not to sure what this guy is saying. Definitely a picture would make more sense.

 

More info please, the flutter drives me nuts!

 

I'll try to get a picture later today. What I'm saying is that previously my bov and my mbc were both running off the same vacuum line from the intake manifold. With that arrangement I always had part-throttle flutter with any aftermarket arrangement I used.

When I separated the two, when I ran 1 vacuum line to the bov and a different line to the mbc, the flutter problem all but disappeared.

So....Want to get rid of bov flutter? Try running the bov on its own vacuum line all by itself, No tees. No nothing. Just one vacuum hose from the intake manifold to the blow off valve. Period.

 

Good info! I got rid of my flutter by installing an IX BOV

 

don't most people run separate lines for the bov and mbc? I thought you had found a break through. THis seems to be a breakthrough for you.