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RE: [VintageLambo] another dumb brake booster question

Paul F Pringle

Yes, I guess there is lots of ways to look at this problem just proving many minds are better than one. The valve over lap could give rise to a thing called back streaming causing the vacuum to be partly released by the dynamics of the engine.With regard to the closed throttle, air still enters the engine at iddle or the thing would not run, it is this air passing through the engine that creates the vacuum in the way already explained, . The easy way to resolve this is to put a vacuum guage on the two engines and measure the different readings. think about an under bottle spray gun, as the air passes through the nozzel the venturi vacuum sucks the paint up the pipe and sprays it out the nozzel against gravity.The through put of any car engine will in any event be far greater than the small volume occupied by the booster.I do agree about the poor performance of the Girling items Iguess they were cheap at the time, we have them on loads of European classics and they never seem as sure as integral booster cylinder systems. Regards Paul -----Original Message----- From: Dennis Briddell [mailto:dbriddel@cisco.com] Sent: 20 May 2004 15:36 To: VintageLambo@yahoogroups.com Subject: Re: [VintageLambo] another dumb brake booster question Paul, The vacuum used by the brakes is created by the closed throttle bodies, not the venturis. This vacuks the paint up and blasts it out the gunum is quite substantial, typically 20"+. Cam timing (i.e. valve overlap) also has a large impact on vacuum, and can significantly reduce vacuum at idle. Dennis Paul F Pringle wrote: >Hi Sheldon,I can give you a definitive answer on this as I have worked in >the scientific vacuum engineering industry for design and development for >well over twenty years. first point, we are talking very poor vacuum >pressure 1-10 m/b. Secondly this vacuum is achieved by venturi effect >through the manifold, it is therefore more dependend on air flow velocity >past the venturi and the size of the venturi than size of engine the only >other governing factors are the size of the volume to be evacuated i.e. pipe >work and booster size, given that this is a fixed amount in this case it can >be disregarded,the only effective difference would be down to manifold >design and sighting of the take off point. >Basicaly I don"t think its an issue. Regards Paul > >-----Original Message----- >From: shel_elias [mailto:shel_elias@hotmail.com] >Sent: 19 May 2004 14:23 >To: VintageLambo@yahoogroups.com >Subject: [VintageLambo] another dumb brake booster question > > >Hello: Just wondered if the girling brake boosters will function >with a chevy 350 engine- such is the case with my Chevaghini. I >don"t know if the v-12 produces more or less vacuum then a 350 >engine.The entire brake system appears to be Lamborghini, but it"s >drawing the vacuum from the 350 engine. > > Regards,Sheldon > > > > > >> > > > > > > > > >> > > > > -- ____________________________________________________________ | | Dennis Briddell ==________________|_ ciscoSystems || / | / | 7025 Kit Creek Rd [||________|_________|] RTP, NC 27709 /______=======______ (o) 919-392-2519 [._O ||||||| O/_.] (f) 919-392-6801 |w|$\___u___u___/$|w| (cell) 919-395-4166 |w|/ |w| [w] [w] dbriddel@cisco.com http://www.employees.org/~dbriddel/ ____________________________________________________________ ________________________________ * To visit you