Is it possible to put a BOV on a D/A Supercharger?

Magic M3 · #1 (**permalink**) 07-17-2002, 12:44 PM

Is it possible to mount a BOV or some sort of BOV device to a Downing Atlanta Supercharger setup? Thanks

kumanchu · #2 (**permalink**) 07-17-2002, 07:05 PM

Quote:

Originally posted by Magic M3
Is it possible to mount a BOV or some sort of BOV device to a Downing Atlanta Supercharger setup? Thanks

well you could, but seeing as how you don't have any boost you would need to release it doesn't really make sense.

superchargers are pulley powered; so boost is directly proportional to the speed of the engine.

turbo's have blow off valves because they are powered by exhaust gases; which are not directly proportional to the speed of the engine, especially during shifting; which is why they have wastegates/bov's

Magic M3 · #3 (**permalink**) 07-17-2002, 07:09 PM

I know you can do it since Randy did it on his Supercharged E30 3.2 liter engine.

Since the D/A Supercharger is a positive displacement supercharger, I kind of dont know where I would out the BOV... thats my main question

Magic M3 · #4 (**permalink**) 07-17-2002, 07:09 PM

I know you can do it since Randy did it on his Supercharged E30 3.2 liter engine.

Since the D/A Supercharger is a positive displacement supercharger, I kind of dont know where I would out the BOV... thats my main question

kumanchu · #5 (**permalink**) 07-17-2002, 07:38 PM

mmmm iiiinteresting. i'd like to know more!

Stealth · #6 (**permalink**) 07-17-2002, 09:09 PM

for what purpose

JCM3 · #7 (**permalink**) 07-18-2002, 02:32 AM

Since its not a centrifugal s/c and doesn't have any misc. piping I dont know how you would be able to mount it. It wouldn't be worth the time.

jagsm3 · #8 (**permalink**) 07-18-2002, 07:16 AM

I have a vortech sc on my 3.2 99 m3. Could I put a bov on it and were would it go

kumanchu · #9 (**permalink**) 07-18-2002, 06:19 PM

i'm kinda wondering if it would work anyway. do you want it just to say you have a bov or to actually make the "pssssh" sound that turbo cars are so famous for.

Magic M3 · #10 (**permalink**) 07-18-2002, 07:22 PM

Jags M3.... you can put a BOV on your Supercharger. It is a centrifugal so you should have a pipe that goes between your supercharger and throttle body. Just put the BOV inbetween there. It takes drilling a hole in the pipe and welding the BOV on to it. Good luck.

Solokron · #11 (**permalink**) 07-18-2002, 10:24 PM

Oh damn. That sounds tempting.

kumanchu · #12 (**permalink**) 07-18-2002, 11:27 PM

so exactly what "excess" boost is the bov venting, and when does it happen?

isn't this like putting some huge spoiler on the back of your car; really pointless? how does this really differ from "rice" thats bashed here all the time?

Magic M3 · #13 (**permalink**) 07-19-2002, 05:11 AM

kumanchu,

Do you know a BOV works mechanically?

Excess boost arrives more prominently in a turbo since the turbo is driven by the exhaust gases of the engine. Since the BOV is located in the piping which lies between the charger and the throttle body, release your foot off the gas pedal actuates the BOV since the throttle body closing is essentially creating a barrier. "Where does the excess pressure go?? If you didnt have a wastegate or a BOV, the excess air would get built up in the pipe causing the air to go backwards causing the turbo impellar to reverse spin.... BAD for the Turbo... imagine going in reverse and then going to drive right away (of course not to that extremity). When releasing your foot off the gas, the turbo is still spinning so the gas built up from this remaining spin gets let out from the BOV into the atmosphere. The BOV can be set manually via a spring loaded gadget which adjusts what psi you want the pressure to release at.

Now... for superchargers.... you get a build up of pressure but not to the same extreme as turbo's which explains why.. if you hook up a BOV in a supercharged car... its not as loud. The supercharger is always running in proportion to your rpm speed so on full load.... you create enough boost to be released from a BOV. All superchargers have a by-pass valve which is like the same as a BOV except in a bypass valve... the extra boost gets re routed back into the intake arm before the Supercharger I beleive..... more beneficial and more practical than the BOV. Its all about the sound of the BOV that I think most people are attracted to.

jagsm3 · #14 (**permalink**) 07-19-2002, 06:16 AM

Thanks

kumanchu · #15 (**permalink**) 07-19-2002, 08:08 AM

Quote:

Originally posted by Magic M3
kumanchu,

Do you know a BOV works mechanically?

Excess boost arrives more prominently in a turbo since the turbo is driven by the exhaust gases of the engine. Since the BOV is located in the piping which lies between the charger and the throttle body, release your foot off the gas pedal actuates the BOV since the throttle body closing is essentially creating a barrier. "Where does the excess pressure go?? If you didnt have a wastegate or a BOV, the excess air would get built up in the pipe causing the air to go backwards causing the turbo impellar to reverse spin.... BAD for the Turbo... imagine going in reverse and then going to drive right away (of course not to that extremity). When releasing your foot off the gas, the turbo is still spinning so the gas built up from this remaining spin gets let out from the BOV into the atmosphere. The BOV can be set manually via a spring loaded gadget which adjusts what psi you want the pressure to release at.

Now... for superchargers.... you get a build up of pressure but not to the same extreme as turbo's which explains why.. if you hook up a BOV in a supercharged car... its not as loud. The supercharger is always running in proportion to your rpm speed so on full load.... you create enough boost to be released from a BOV. All superchargers have a by-pass valve which is like the same as a BOV except in a bypass valve... the extra boost gets re routed back into the intake arm before the Supercharger I beleive..... more beneficial and more practical than the BOV. Its all about the sound of the BOV that I think most people are attracted to.

yes i'm aware of what a BOV is for; you are somewhat correct in what you are saying. a bov allows excess boost to be released in a turbo charged system. why? because if you don't dump that extra boost; you put MAJOR stress on the turbo; so to keep the turbine spinning freely and not locked up between exhaust pressure and the boost it's created; it dumps the excess boost. in the case of a supercharger since the screws/turbine don't spin freely to begin with and that since they are mechanically forced to operate by however fast their pulley is spinning; there isn't really "excess boost" since the boost is moderated real time by the pulley/enginespeed.

a turbo will never "reverse spin" because all turbo systems have a wastegate/bov in their design. all wastegates are spring moderated; but can also be controlled past their spring's stiffness via a boost controller. i think that is the "gadget" you may be refering to. I think you are mixing up the bov and wastegate sometimes.

in anycase; my point still remains, why put in a BOV? it still rice in the sense that its not there for any real purpose to but to attract attention by mimicking something else (a turbo in this case) The supercharger does not experience intake surge; and the bypassvalve (or in a turbo system wastegate) does not warrant the use of a blow off valve. The reason why it would be so quiet on a superchargeed system is because its not actually preventing surge any longer; rather than just leaking your boost.