006Banger

ok i know you can put a BOV on a procharger but how exact do i hook it up?

edit---Does it just not get hooked in to the air filter like it is now?

eternal981

Basically.

But you might have to do a little fabricating to get a blowoff valve to fit. Odds are, you have the stock procharger tubes, which only have a 1.5" connection at best, and the BOV will probably come set to bolt up to a certain flange.

this next part is a little long winded, if you don't care about how i'm going to make my BOV connection...

No big deal if you are even remotely experienced with any kind of fabricating. Metal fab is better, but any good mechanical background will probably give you the skills you need to figure it out. If I end up going with a BOV also (see my poll), I'll probably end up making a tee out of a piece of 3" copper tubing. It's technically "too big". 3" ID, whereas the procharger tubes are 3" OD (at least mine are). so one will fit over the other (but don't rely on that to do anything, i'm just saying it for comparison). i'm planning to braze a piece of whatever size copper tubing i need onto the wall (i braze fittings like this quite a bit, and they all hold 150psi for yeeeeears. i WISH i could see that kinda pressure actually work on my motor!!!). I'll also have to head to a local scrap yard or machine shop and see if I can get a piece of brass plate, around 1/4" should work. drill an exact size hole to fit over the branch of the tee, braze that into place, bolt on the BOV and gasket, use 2 rubber couplings to tie your intake lines to the tee, hook up the vacuum line, and you're done.

p.s. - if you swap them out, don't forget to plug the hole on the inlet side of the blower where your bypass valve ties in now.

nanaki

don't do it. there's a reason centrifugal blowers use a bypass and not a BOV.

blackbetty01

You can't use a blow off valve on a Supercharged Draw through system. A Centrifugal supercharger builds boost with rpm, even with vacuum. So that would blow any Blow Off Valve OPEN under vacuum, making your car run extremely rich and unable to build boost. Someone please correct me if I'm wrong but this is the way I understand it.

QuickShortBus

You need to use a waste gate for something like this.

eternal981

blackbetty01 is right about the draw through system. you need to know where your MAF is located first. mine is RIGHT before my throttle body, so air blows through it. relocate it, and you should be good.

as far as a wastegate goes, why would he need that? he's not looking to limit boost, just dump it to the atmosphere instead of recirc to the intake. at least that's the way i read it. How would a wastegate do that? Maybe you have a different idea than I'm thinking.. here's what I understand wastegates and BOV's to be..

The following is a direct quote from http://www.streetracersonline.com

"Without a wastegate, the amount of boost that a turbocharger creates varies with the pressure of the engine's exhaust. This happens because exhaust pressure varies with relation to the engine's speed (measured in RPM's). This implies that as an engine reaches higher RPM's, increasing amounts of boost will be created by the turbocharger. The problem with this is that an engine can only accomodate a given amount of boost. Most stock engines are only meant to take about 10 PSI if not less. In order to regulate the amount of boost that comes into the engine, a wastegate acts as a door only allowing a given amount of exhaust to hit the turbocharger's exhaust turbine. Once the engine starts producing more exhaust pressure then the wastegate system will allow, a flap is opened to redirect excess exhaust away from the turbine blades. In turn, this is where a wastegate gets it's name. It's a gate to carry away waste. In order to regulate when a wastegate opens, a boost conroller can be used."

"Now let us differentiate BOV's, diverter and bypass valves. First, a blow off valve (seen top right) is common to high performance applications in that it provides the least bit of compromise. A BOV essentially releases this pressure straight out into the atmosphere. Quite often you will find that these units take on particular shapes, making them resemble musical instruments. I guess some people out there really like to flaunt their gadgets. Just wait ti'll you see how much they impress the ol' 5-0. Aside from this legal dilemma, the second problem you encounter with BOV's is that the mass air flow sensor will cause the engine management system to "think" that the air will go into the engine and in turn will release an appropriate amount of fuel for it. However, a BOV system will vent this air out before it gets to the injectors causing your mixture to run lean. In turn, this will result in unburned fuel to escape into the exhaust system. This is why you often see flames and hear those "pop's" in rally cars. It is unburned fuel exploding in the exhaust system. Doesn't take a genius to figure out that this is not the smartest application for the day to day car. For this reason, reasonable tuners will usually employ a bypass or a diverter valve (see left). These units essentially redirect this pressure back behind the compressor causing the net flow of air to remain constant. This in turn slows the turbine down gradually and allows the air flow sensor to work appropriately."


the reason they give for NOT using a BOV is because of the air flow sensor (which is your MAF). i have yet to have anyone explain to me why you can't use a BOV on a supercharged engine, other than your MAF location. turbos and centrifugal blowers are not very different. different driving mechanisms, but the EXACT same theories apply as far as compressor surge is concerned.

if i'm wrong and somebody can give facts as to why you can't use a BOV on a supercharged engine with a blow-through maf, please tell me.