<VV> Curing my off idle "stumble"

[FrankCB]

Bob,
     This is explained in my Turbocharging Chapter 33 on page 151 of the Corvair Basics manual.  You need to defeat the vacuum advance at idle that you now have just like all other non-turbocharged 
Corvairs do.  The vacuum advance should "come in" only as you advance the throttle opening off idle speed.  Check Ray Sedman's site (www.American-Pi.com) to see if he still offers his kit to do this or assemble your own using a solenoid valve and a microswitch on the YH carb linkage..
     Frank "boost is the substitute  for cubic inches" Burkhard

In a message dated 04/20/09 23:53:45 Eastern Daylight Time, bgilbert at redshift.bc.ca writes:
Hi, 



I'm still trying to track down an annoying off idle stumble. 



The car is a 66 180 , engine rebuilt, runs fine otherwise. I have the 
correct turbo distributor and a Dale advance/retard unit and I'm running the 
Clarks knock eliminator with dual sensors 



When I set the timing to 22-24 BTDC at idle, I can blip the throttle and 
watch the timing retard by about 8 degrees (exactly as reported on Ray 
Sedman's American Pi site).  I think this is the cause of the stumble. 



As an experiment I pinched off the vacuum line and sure enough the ignition 
doesn't retard and the stumble is significantly reduced (and the car feels 
peppier) 



Would running in this mode pose any problems in the long run or at highway 
speeds given that I have the knock eliminator? 



Any other ideas or suggestions? 



Thanks in advance. 



Bob