[Healeys] HD8 Slow Run Valve

[Bob Spidell]

Alan,

Temperature, humidity and the local barometric pressure affect air 
density, and overall engine performance and behavior.  How does the 
engine know whether the mixture came through the slow run valves or the 
throttle plates?

My BJ8's idle varies depending on the aforementioned conditions, but 
only slightly unless I get a few thousand feet above my usual sea level 
conditions, or it is exceptionally hot (lower air density).  It is 
always steady and smooth.

bs


Alan Seigrist wrote:
> On HD8s, cracking the throttle plates open works ok but bypasses the
> purpose of the slow run valve, which is to give you a nice steady &
> smooth idle.  If you crack the throttle plates open, you'll have a
> couple hundred RPM variation depending on temp / conditions, etc.
> Incidentally on a car with triple HD8s like an S1 E-Type you'll never
> get idle below 800 or so if you crack open the plates.
>   
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Bob Spidell           San Jose, CA            bspidell at comcast.net

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