[DML] Re: Ported PRV Vacuum Ports

["content22207" <brobertson@xxxxxxxxxxxx>]

Don't have a throttle assembly in front of me, but if I remember
correctly PRV ported vacuum ports are traditional slits. As the plates
open, more of the slit is exposed, increasing the amount of vacuum
allowed through. This is the way ported vacuum has been done for
decades (carburetors).

The advantage of ported vacuum is it varies with throttle plate
activation. DeLo simply takes off from the driver's rail -- 100% of
whatever happens to be in the manifold at that time. Quite a jolt when
the plates are only partially open.

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, Martin Gutkowski - DMUK <martin@xxxx>
wrote:
> Not quite correct - there's full engine vacuum at downstream of the 
> throttles but this drops as the throttles are opened. Full throttle
sees 
> little or no vacuum advance.
> 
> Basically what the DeLorean setup does is to run more advance under 
> light throttle - which is done on a lot of modern engines to clean up 
> emissions (making sure the burn is complete). Euro PRV's circa 81
didn't 
> worry too much about this.
> 
> There are numerous different vacuum setups in my Renault manual - some 
> even using the delay valve on ignition advance for engines used at high 
> altitude
> 
> Martin
> 





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