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Re: [VintageLambo] Espada Brake Vacuum

Dennis Briddell

my CT has very similar vacuum numbers (though warm idle is higher ~5-7" Hg) and there is no problem with the brake booster providing proper assist. maybe the vacuum resevoir is undersize? Laust Pedersen wrote: >So I finally got to measure the vacuum that the brake boosters see >and here are some numbers: >ight >vacuum in the crank case) gained only ½ in Hg. > >7.5 in Hg at about 1000 rpm idle cold and warming up >11 in Hg at about 2500 when warm >2.5 in Hg when thoroughly warm idling at about 800 rpm >15 in Hg on overrun from 3000 rpm >19 in Hg on overrun from 5000 rpm >Blocking the longitudinal balancing pipes (from pulling sl >In my installation the flow path to the crankcase is restricted to >about 1 mm diameter on both sides. >I simulated the standard set-up by blocking the flow to the Idle >Speed Motor (ISM, unique to me), which is connected to the two >longitudinal vacuum tubes. > >It is surprising to see that the vacuum increases as a function of >rpm under no load conditions. >Fully warmed up and at low idle the vacuum is inadequate to assist >the brakes, so my previous assertion that driving in slow traffic >will deplete the brake boosting is certainly explainable in my case. > >I would be very interested to see numbers on other 4LV12 engines. >Otherwise I will have to conclude that our engines really need an >electric vacuum pump which typically generates around 20 in Hg. > >Laust > > > >