is it possible to put a blow off valve on a cooper s and if sooo....any side effects in the cars performance...

[obehave]

No
There's about 5 recent threads on this
The answer is still no

[Jaffa Racer]

Quote: Originally Posted by obehave

No
There's about 5 recent threads on this
The answer is still no

So the supercharger is self regulating as far as pressure goes

Theoretical question for ya....

say the safe boost pressure you can use is 2 bar, what adout fitting a pully to give this at 1500rpm then have a valve to regulate the pressure at 2 bar all the way to the red line?

Mechanicaly this has to be possible? the only possable problem i know of would be over revving the water pump? so remove pump and fit electric one, or am i correct or talking complete poo

just looking for a different way to crack the nut

Kev...

i know blow off valves are possible to be mounted on supercharged cars....i just found it weird that the trottle body was before the supercharger

[obehave]

Quote: Originally Posted by djscooby

i know blow off valves are possible to be mounted on supercharged cars....i just found it weird that the trottle body was before the supercharger

I don't know where you "know blow off valves are possible to be mounted on supercharged cars" but it must be from another source than the people that design them.

Here's [url=http://www.automotive.eaton.com/product/engine_controls/superchargers/whysuperchargers.asp[/URL]

It'll also explain why the TB is before the SC.

blow off valves are used to regulate boost in charge pipes.....that is why stock sc cars there is a boost recyling valve....which does the same funtion as a diverter valve....bov's do the same function as diverters but putting the boost air into atmosphere...jackson racing sc for honda's have optional bov flanges on them...i also had a bov on my vw corrado g60

ps your link didn't work

[kapps]

If you look at Eaton's site (don't have the link at the moment), you will see that the SC the MINI uses encorporates a "bypass" system. When you are just cruising along and not using any boost, while the SC is still spinning (since it's not clutched), the bypass is just letting all the pressure out so the engine doesn't have to work so hard. This also increases fuel economy and lowers noise. As soon as you give it gas, the valve will close and since the SC is already spinning, you will have instant boost.

A way to see this is drive in 2nd gear (say 3000-3500 rpm) and you'll notice that the whine is non-existant. Floor it and there it is - instantly.

There's some video clips of a twinscrew SC around here somewhere and that car doesn't have a bypass system so it whines from idle to redline .

[obehave]

Quote: Originally Posted by djscooby

ps your link didn't work

Fixed the link.
Just spent a while at Jackson Racings web site. Didn't see any parts for VW but did see that every supercharger they have is an Eaton.
Eatons have diverters. The function of a diverter is different than a BOV.
BOVs funtion on compression systems where the TB is after the compressor, turbo or centrufugal

[obehave]

Quote: Originally Posted by djscooby

ps your link didn't work

Fixed the link.
Just spent a while at Jackson Racings web site. Didn't see any parts for VW but did see that every supercharger they have is an Eaton. Judging by their pics every one for every design uses a recycling diverter. Apparanly vacuum operated.

Eatons have diverters. The function of a diverter is different than a BOV.
BOVs funtion on compression systems where the TB is after the compressor, be it turbo or centrufugal SC. Although I've never heard of a BOV for a centrifugal unit. I'm no expert and I'm sure the design is possible it's just contrary to common sense and any design I've ever read about.

A diverter works on the Eaton not as a way to dump excess pressure at high or over boost but just as a way to vent pressure wave rebound at throttle closing. Since boost occurs after the TB the pressure is recycled into the induction path ahead of the TB.
Yes you can route the excess in a turbo system back prior to the turbo itself.
It's still not the same thing.
A properly designed SC unit will deliver it's max boost where/when needed. You do not design it to create too much boost and then dump the excess. That's just wrong.

Here's the best pic I could find of Jackson's SC.
Maybe they just stopped doing the dump to atmosphere thing. I wonder why?

i know in the past that jackson had a kit to put a bov on....maybe not anymore i guess....i had a bov on my vw corrado with the stock sc unit...it seemed to work fine....i can see now why they put the trottle body before the sc to limit the noise....which kinda sucks i like that sc whine at idle.....i find it kinda pleasing.....as do i like the bov noises....however i don't like a sacrifise in power....

[obehave]

Quote: Originally Posted by djscooby

i know in the past that jackson had a kit to put a bov on....maybe not anymore i guess....i had a bov on my vw corrado with the stock sc unit...it seemed to work fine....i can see now why they put the trottle body before the sc to limit the noise....which kinda sucks i like that sc whine at idle.....i find it kinda pleasing.....as do i like the bov noises....however i don't like a sacrifise in power....

Need to find a way to use one of the ribbed belts they use on the roots blowers.
Very cool sound. Had a Saleen pull up next to me yesterday. The belt noise was a dead give away even at idle.

I have no doubt you had what you say you did. Apologies if I sounded doubtful about that. I'm just puzzled as to why.

BTW
Here's one of my favorite sites for SC info.
http://www.superchargersonline.com/content.asp?id=31