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Re: SU carb advance port

To: 6pack@autox.team.net
Subject: Re: SU carb advance port
From: Jimandruthhome@aol.com
Date: Wed, 13 Sep 2006 23:03:47 EDT
James Juhas writes:

A  supplementary question is: does this engine really need this feature 
for  performance reasons, or is the vacuum retard only an accommodation 
to  emissions control?  I am converting this car from downdraft webers to  
SUs and this provides me with a vacuum signal at the carb which, I  
believe, will be present at partial and full throttle, and this seems  
wrong to me to connect this to a retard unit.  In the normal Stomberg  
setup, where does the retard vacuum unit port attach?
I've run HS6 carbs since the mid-80's.  The port is indeed advance,  not 
retard.  I carefully drilled a port for retard in the rear carb and  plugged 
the 
advance port when I installed mine, but found I was still having  scary rises 
in engine temperature in summer traffic (Jersey shore in August,  including 
Garden State Parkway with its many toll booths, is murder).
 
I wound up plugging the vacuum line from the retard port.  Summer  traffic 
jams were no longer an issue, and performance was not affected.  
 
If you can pass emissions inspection without the retard functioning (I  
could), you don't need it.
 
Jim Knight
'71 TR6 with HS6 carbs and late model, 13 blade fan (also an  improvement in 
summer traffic for early models)




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