There is a serious debate about the BOV .. I am not mentioning any names but I receieved info almost prooving that the BOV will in fact destroy the clutch sooner then if you did not run a BOV at all .. this was not from an anti riva person as they sell and use many riva parts ... i persoanlly run the riva across the board on my ski .. from the BOV to the s/c imp the intake grate the cold air kit etc etc ... HOWEVER i would like to know rivas take on this ... did they do the dyno testing some people have done ..is it true that the tests showed that without the bov the sc clutch slipped less. the impeller speed matched the crank speed more closely with no bov. the theory behind this is the sc impeller is using the air pressure behind the closed throttle body to slow down with the crank instead of free wheeling.

again .. presently i run one on my RXP so i would like to know rivas take on this

Crazed, as yourself this. The other claming it causes the cluth to slip more. How did they measure it slipping more? Unless they connected some type of external SC impeller RPM measuring device they have zip zero nada idea that it's "Slipping more"
I would like to see the setup that they used to make this claim (you won't see it).
Riva Dynoed the bov, which altough better than nothing, I doubt they even monitored SC rpm. But is more than the detractors ever did.
No one as far as I know has had a clutch failure runing the BOV. Lots have failed not running it(stock clutch).

EXCEPT for the fact that Crazyed posted no facts to back up his assumption, as a reader, I understood the question, and it seems innocent enough. He just seems a little concerned about his purchase due to some "mystery data" from an outside source. It never hurts to ask.

I would like to know what RIVA has to say about this .. Not that "it works" ...

I've posted this several times and I'm sure I'lll have to post it several more times.

Our position is still the same. Our BOV is a preventative measure. The clutch on pre `05 model SD Superchargers is prone to slippage and wear. The `05 models have an improved clutch that can slip, but shouldn't wear as much. Why allow it to slip or wear at all? We've been running our BOV in our Stage I equipped test craft for almost a year now and we've run a BOV as part of our Stage II Kit in numerous races this season. All without one single problem.

I read the same info and it came from a very reputable source. It made me go hmmmm as well. Riva is there any theory behind the BOV that supports its usage?

having seen a gear driven supercharger in other applications in detail I can offer you an explanation on this one:

When the throttle plate closes and the SC continues to spin it builds up pressure in the plenum. That pressure gets to a certain point and then has to go somewhere. With no BOV it will go back through the SC. Given the size of the cavity and the volume of air the sc moves (especially with the other impellor in place) this happens quick. This is bad simply for the reason that the gearing in that SC is designed to go one direction (to compress). Air coming back through it will try to create resistance against the drive gearing for the SC which is where the clutch comes into play. It will disengage under pressure allowing the air to escape, etc. However the problem is there is a certain amount of negative resistance required to engage the clutch which could also be classified as wear as that additional air tries to force the SC in theopposite direction prior to the engagement of the clutch. Not to mention no matter how precise of a device at the speeds SC's spin to compress even 1 additional atmosphere (8psi +/-) it's almost impossible to have a clean engagement.

That negative resistance working against the gear system (in this case trying to make the SC slow down much more rapidly than it would traditionally) is putting strain on the system in the opposite direction it was designed to be strained. You should also realize that in forced induction supercharging traditionally puts considerably more strain on an engine than turboing...

The BOV assembly would eliminate that by releasing that air that creates the strain befoe (or maybe even at) the same point the clutch is designed to engage. No matter what happens with that air supply, if the SC is gear driven it's going to spin very closely to the ratio it was designed to spin at based off the gearing from the crank. If there's air in there trying to force it's way through that's just going to create even more strain on the system. That's the reason for the clutch assembly in the first place but the first year design wasn't really up to the task it seems.

Just my 2 cents, take it or leave it. I've yet to see a high hp application (which given it's displacement the RXP certainly is) of forced induction that doesn't use some type of method for bypassing boost. And most of those applications use belts which would seem to be much more capable of handling negative resistance as they'd just slip. No intermeshing teeth to worry about...

Very well put Sirhc. Thanks for saving me all that typing!

Slow day at work...been bored out of my mind and finally found something worth spending a little time on...

Some info I read mentioned in haed to head tests, the impeller speed matched the crank speed more closely with no BOV. And that the theory behind this is the SC impeller is using the air pressure behind the closed throttle body to slow down with the crank instead of free wheeling. With no air pressure present, the SC impeller is affected more by inertia.

I certainly don't mind overdoing it for reliability sake and buying the Riva BOV, but if for some reason the use of a BOV actually adversely affects reliability in this case, I don't want to get into that scenario. Thoughts?

I can understand your being concerned. But I don't know what more or how else I can type it. At this point you're going to have to make your own decision based on the information you've obtained as well as its source.

Being that we've been in business for over 25 years, won numerous industry awards for our performance products, have always stood behind our products and have continued to grow positively with the industry I'd like to believe that you can feel confident that when we tell you we're offering a product that won't damage your engine you would be inclined to believe us.