hey whats up everyone, i was talking to a friend of mine with a jetta vr6 and he was telling me how he wants to get a supercharger. he said that someone told him he can put a BOV on it. is this true? and will we be able to put a BOV on the trd SC. sorry if the ? sounds dumb im just curious. thanks

 

Yeah you can have a BOV on a supercharger, if i remember
correctly of what my friend told me, the only way to have
a BOV on a S/C, is if the S/C is a direct mount onto the driveline(something like that)

I showed my friend a pic of the TRD S/C and he said you
should be able to mount a BOV on it.

But obviously the TRD S/C isn't out yet, no surprise, so you
cant see for yourself

 

Ok someone fill me in here, what's the purpose behind a BOV (besides the cool sound of course)? I know the wastegate limits the produced boost of a turbo but what does the BOV do and what advantage would it give?

 

lol i have no idea but the sound is sweet.

 

It just releases the excess air. hence blow off valve.

 

So in theory since a supercharger produces a more constant boost level than a turbo, would excessive air be an issue? And would it even benefit a S/C?

 

you need to control the boost, the blowoff valve vents out the boost when it is not needed.
you don't want to have full boost in the motor when shifting...all kinds of things can go snap if you do....

superchargers are all driven like an alternator (by a belt pulley setup) thats what classifies them as a supercharger...

if the supercharger is a positive displacement style (it replaces the intake manifold) it does not use a blow off valve....

 

Boosted air is rushing into your throttle body, you shift, the throttle body closes, excess air needs a place to go. Without a BOV or diverter that air goes right back to where it came from, namely the turbine, which is still spinning. Sonic air bounced back to a turbine spinning at xx,000 rpm's = crunched up turbos. This also occurs when getting off the gas in a hurry, i.e. setting up for a turn ala Rally Style.

 

So if that's the case then wouldn't the TRD have one by default? Sounds like it's neccessary.

 

no, the TRD one is low boost and low cost (hehe that made me laugh..) imagine the cost if TRD included a BOV, controller and extra pipe work.... add another thousand....

 

Speedpunk, you are correct. The turbo pushes constant air to the throttle body. Went you step on the clutch the throttle body closes and force the air to go back into the turbo causing the turbo to slowdown. The BOV works with vacuum as soon as the manifold has vacuum (throttle body closes) the BOV opened and release pressure and give you that great sound. Most stock commercial turbo cars don’t have to have BOV simply because they don’t produce lots of boost to slow down the turbo in a way that the turbo can get damage. My turbo supra comes with a BOV from factory but you can not notice because there is no sound coming out of it, the release pressure is directed back in to the intake by the air filter. The advantage in having a BOV is simply that after shifting from one gear to the next the turbo don’t have to slow down by the back pressure therefore improves performance while racing.

Hope this can help!!

 

The TRD supercharger system will come with a diverter valve so in a way it does have one.

There are a few options to these issues. There are two different kinds of BOVs and then there's a diverter valve.

Atmospherice BOVs (the loudest ones) vent out into the atmospher, hence the name. HKS, Greddy, Turbo XS, Tial, Blitz, Apexi, all make these. Some of these can have recirculation kits added to them, making them a recirculationg BOV (the second type of BOV). The last is just like a recirc-bov, the diverter valve. When excess pressure comes back at the valve, a diverter valve simply routs air right back to the intake (the location by the air filter, where air isn't charged yet).

Now most would think an atmosperic BOV is best, it may not be. Cars that have MAF read air in CFM and tell the ECU how much fuel to add. If you vent (atmospheric bov) the air is lost, and the wrong fuel mixture hits the engine causing it to run rich and occasionally stall out. You may also foul up spark plugs from this situation. By recirculating, some of the sound may be lost, but you will more accurate fuel curves, making the car run better/faster. The other setup (MAP systems) stands for Manifold Absolute Pressure. MAS stands for Mass Air Sensor. MAP systems read how much pressure is hitting the intake manifold and adjusts fuel according to those reasons. Because of this, it doesn't matter what kind of BOV you use.

Many cars use MAF stock. A lot if Hondas, and the new SRT4 uses a MAP. MAF systems have an ok solution. The HKS EIDS (Electronic Idling Stabilize).

Quick Blurb from HKS:
"The HKS EIDS has been developed to buffer dramatic airflow meter signal fluctuations. By buffering these fluctuations the EIDS prevents engine stalling or stumbling associated with sudden imbalances in air/fuel ratio of airflow meter-equipped vehicles that utilize atmosphere venting blow-off valves."

I sell this system and strongly recommend it if you are having issues venting on either a turbo or a super charger.

To also answer the question, a BOV can be mounted on the TRD S/C system for the tC because it uses a centrifugal blower.

Hope this helps clear things up.

 

To also add, HKS has vehicle specific systems. I do know you can adjust the readings. So I'll call HKS if anyone is interested or wants this part for their car. I had it on my Evo and it worked well.

 

if you worded this correctly it might have helped....

steping on the clutch does nothing to the throttle or the throttlebody....

 

why would u want a bov on a supercharger? all superchargers i've heard sound bad ___ as is.

 

i dont like the noise that sc make they make a high pitched whine and as far as the blow off valve joe@dezod is right they can cause the car to stall my friend through one on his wrx back when he had it. it sounded so cool but it stalled in cold weather. he wont throw one on his evo becouse of that i have never had a car with boost but i have driven the wrx and other friends 99gtp with a samller pully and i like the turbo more but thats just me some peaple might like the noise of a sc

 

He could be right if he's assuming when you step on the clutch you completely let off the throttle. Letting off the throttle is what closes the plate...sooo both are right!

 

never assume....if your really racing, you might just bang gears with out letting off the throttle....

plus, there are many people here that don't know enough about cars to assume that...

 

This is a perfect explanation, and one that needed to be included. There will undoubtedly be folks determined to put a BOV on a MAF equipped car, with many a CEL and limp-home mode encountered. I saw this first hand with 1.8T's on VW's. There are hybrid diverter/bov's available, that still recirculate enough air to not trip the CEL's, but let out enough air for the sound. Whatever floats you boat. I think the sound of a supercharger whining, or a turbo spooling up is all the noise I want/need. I tried that hybrid valve, and everyone that rode with me kept asking, "Do you have a leak or something?", "What's wrong with your car?" or "What was THAT?"

 

Hopefully you don't do this too much. Unless you like buying clutches haha.