Re: [DML] SuperCharger and Engine Vacuum

[mike.griese@xxxxxxxxxxxxxxxx]

Nick - you will need to provide an alternate vacuum source if you 
supercharge your car.  An electric vacuum pump and a reservoir 
will be enough to run accessories like your power brake booster
and HVAC system.  Devices that rely on the difference between 
manifold pressure and absolute pressure - like the advance for 
the distributor need a different kind of change.  The distributor on 
my Esprit uses a push-pull mechanism.  The diaphragm that drives
the advance has a port for a vacuum line and one for a pressurized
line.  This way, as boost builds, you don't lose advance.  I haven't
looked at what systems use manifold vacuum, but a similar system
could be devised for them.

--
Mike


-------------- Original message from "Nick" <nicholden@xxxxxxxxx>: -------------- 


> Hi, 
> 
> I have almost completed a supercharger and EFI installation. 
> 
> My question is how exactly does the crankcase get it's vacuum?? and 
> what purpose does the brass tube under the fuel distributor serve in 
> relation to this (if any. 
> I have removed all the old EGR system so do i still require the hose 
> off the brass tube to the small tube on the filler cap?? The large 
> tube on the filler cap i have connected to the intake before the 
> throttle plate. 
> 
> I didnt want to blow the oil cap off the first time i start it! 
> 
> Is the brass tube under the fuel distributor feeding off the 
> manifold or does it go right through and feed into or off the valley 
> (crankcase) 
> 
> How would this function now the manifold will be under preasure and 
> not vacuum?? I also have a blow off valve that will re-circulate 
> the boost back into the intake at idle. 
> 
> All advice is greatly appreciated. (hope i have explained what i was 
> trying to ok!) 
> 
> Cheers, Nick - Sydney 
> 
> 
> 
> 
> 
> 
> 
> 
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> 

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