The stock BOV on the new GTI is electric, I found that out when installing a new BOV on my buddy's. Pretty nifty design, and I dident know they were electric.

 

increase the diameter of the flow cross section = lower mach numbers = quieter

 

is that you?

 

yes, OR use a pre-compressor throttle body mounted like that:





Notice that this doesnt replace the actual throttle body which is still in the original location, but it closes in conjunction with it, thus removing any possibility of flutter. An e-BOV might be easier and simpler though.

 

Yeah, I bet I could port on this BOV a bit and make it quieter. Pretty sure it's designed to be loud.

 

GFB Electronic BOV

Super expensive though. They also have the Stealth which is basically the same, but without the electronics. I've read alot of great reviews about GFB online.

Vash-

 

mine is a GFB I love it.. it is super loud though

 

hey pat, here's something for ya:

The All-Electronic Blow-Off Valve!

I also found a local supplier ;-) for the e-BOV @ $18.47 each:

Toro 1 In. In-Line Jar Top Valve with Flow Control (Slip) - 53707 at The Home Depot

The controller doesnt have to be so complex, just something that goes to ground at closed throttle since you don't run a MAF. Or even a vacuum switch if you want to get fancy.

 

Probably also depends on the kind of foam you're using. The samekind principles for making a firearm silencer probably apply. Another material worth considering is steel wool.

 

Well, I'm gonna do the intake next before I finish up the BOV. But I was figuring I'd wrap the BOV in another layer of foam, then wrap it in sheet metal and put a couple hose clamps. Might be too restrictive, but if so, I can make the steel band smaller. So we'll see. I'm not wanting to change BOV's right now. I can't while I'm at college.

 

I've read that even a long hose helps muffle the sound- and you can aim the exit. I haven't tried it yet... my eBay bov isn't that loud.

 

sexiest 1980s 1500hp 4cyl ever made if im not mistaken (which i prolly am)
bmw m12 engine?

 

I believe its a BMW, yes.

 

I bet a tube sock would work great, just double it up.

 

I had a lawnmower foam air filter on mine. That cut noise down by half... There's k&n style breather filters on eBay that will fit most bovs.

 

Did you use foam with a combustability rating? Wat if you backfire :( Some foam likes to burn.

 

Good point. Never heard of that. Link? This is walmart special foam. I'm sure there's something better out there, but I wouldn't know what.

I put a small piece on my manifold and it smoldered to nothing.

 

APS makes a good Recirc.

 

Pat, I agree with you about the noise levels. After I installed a midpipe and header, my car was much louder than I wanted. Before, I could step on it and not get too much attention, but now I get unwanted attention. The added noise isn't worth the 4-6 WHP that is gained.

 

Well if it just smolders it's probably flame retardant already. Why not hold a match to it? If it burns slowly it's the good stuff. If it goes WOOSHpoof then it's bad.

Here's a link to some foam:

Flame Retardant Foam