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I´m sorry if I was a bit unclear. What I ment was that on a turbocharged engine ,the plenum wolume is not that important when under boost, as the turbo will support the air needs. But when in off boost mode a small plenum will hurt engine response. The reason I mentioned the draw through systems is that they use a very small plenum. Christer Bryan skrev: > Christer, I'm not sure about your reference to draw through kits and the > significance of airbox size. > > At 10:38 PM 11/22/99 +0100, Christer Johansson wrote: > >Yes it is insignificant, just have a look at the draw through kits ,like > >Mr turbo, almost no plenum and no pipes ,intercooler. > >But in normally aspirated mode , this is a restriction, hence the > >priority breather valve. B.t.w I´m working on My own version > >of the priority valve , I´m using a 2 stroke reed valve, has anybody > >tried this before? > > > >Christer > > > >shammar@nsk-corp.com skrev: > > > >> Don't worry: we like counter-discussion. That's the point of this > forum. I do > >> think that Abraham is onto something. I believe that the amount of time > it will > >> take to fill the plenum will be insignificant. > >> > >> Bryan <bgoodwin@iquest.net> on 11/22/99 12:26:04 PM > >> > >> To: Bob Shammas/EQA/Nsk-Corp@Nsk-Corp > >> cc: FFDennis@aol.com, turbobike@natvideo.com > >> Fax to: > >> Subject: Re: [turbobike] Carb Question > >> > >> Bob, I realilze that boost response and timing is primarily controlled by > >> the turbine sizing. However, that assuming all else equal. Given a fixed > >> A/R on the turbine, increasing the size of the plenum volume will increase > >> the time it takes to fill it. What I'm not sure of is how dramatic an > >> effect this will have. > >> > >> P.S. Not trying to argue, just making friendly counter-discussion. :) > >> > >> At 07:49 AM 11/22/99 -0500, shammar@nsk-corp.com wrote: > >> > > >> >Realistically you'll never get too much plenum volume. The need for > plenum > >> >volume is all but forgotten on four cylinder engines since the intake > >> events of > >> >the cylinders provide an almost uninteruppted flow out of the compressor. > >> >However, a larger accumulator volume reduces manifold pressure > fluctuations > >> >between intake events. On a twin, you'll run into surge much more > easily and > >> >must have a huge plenum. Having a large plenum is akin to being able to > >> blow up > >> >a balloon with full lungs the whole time. You don't want empty lungs > >> before the > >> >intake valve event has finished. > >> > > >> >Turbine response (how fast it makes boost) will be governed by the exhaust > >> event > >> >and turbocharger matching. > >> > > >> >That's just my $0.02. I've built a few bikes but that doesn't mean > anything > >> >either. > >> > > >> >Bob > >> > > >> > > >> > > >> > > >> > > >> > > >> >Bryan <bgoodwin@iquest.net> on 11/21/99 01:37:26 PM > >> > > >> >To: FFDennis@aol.com, turbobike@natvideo.com > >> >cc: (bcc: Bob Shammas/EQA/Nsk-Corp) > >> >Fax to: > >> >Subject: Re: [turbobike] Carb Question > >> > > >> > > >> > > >> >I think the only problem you would run into there is that the volume of > the > >> >airbox would be too large. This might cause the turbo to boost later. > >> > > >> > > >> > > >> > > >> >At 10:38 AM 11/21/99 EST, FFDennis@aol.com wrote: > >> >>In a message dated 11/19/1999 23:56:32 Central Standard Time, > ABNZX9@aol.com > >> >>writes: > >> >> > >> >><< Now for another question how about intake plenum and attaching it > to CV > >> >> carbs? Should I buy a set of velocity stack and machine them in > order to > >> >>fit > >> >> an intake plenum to the carbs that way? I have a feeling that the > intake > >> >> plenum I am currently using is robbing me of effieciency. > >> >> >> > >> >> > >> >>You raise another interesting possibility.....If you can encapsulate the > >> >>entire carburetor within a plenum, and then pressurize the entire plenum, > >> >you > >> >>eliminate the need for separate pressurization lines for bowl vents, CV > >> >slide > >> >>vents, etc., as you would have equal pressure operating on all sides > of the > >> >>crab. The pressure in the venturi would be lower than the other areas, > >> >which > >> >>is how a carb works. Your next problem is then to seal the throttle > cables > >> >>and fuel lines where they pass into the plenum. I've seen ram air setups > >> >>like this. It seems to me that a turbo plenum could get away with being > >> >less > >> >>aerodynamic internally due to the mechanical pressurization. > >> >> > >> >>Just my .02.........lots of book knowledge and reading, I've never > built a > >> >>turbo bike (but I have a KZ 900 motor in pieces, bead blasted, for a > future > >> >>project......) > >> >> > >> >>Dennis > >> >>'99 M2 Cyclone > >> >>'87 KLR 650 Urban Assault Vehicle > >> >>'78 KZ900 bike in boxes > >> >> > >> >> > >> >bgoodwin@iquest.net > >> >FZR1000 turbo EFI > >> >(aka The Money Pit) > >> > > >> > > >> > > >> > > >> > > >> > > >> bgoodwin@iquest.net > >> FZR1000 turbo EFI > >> (aka The Money Pit) > > > > > > > > > > > bgoodwin@iquest.net > FZR1000 turbo EFI > (aka The Money Pit)