<VV> Turbo advance/pressure retard

[FrankCB@aol.com]

Matt,
    While you CAN drill the throttle body from the Corvair YH carbs to add 
ported vacuum, it isn't easy to locate the inside opening of the hole correctly 
so that it is JUST upstream of the closed throttle plate and "moves" 
downstream as soon as the throttle is opened.  One alternative is to find a YH carb 
throttle body from an NA car different from the Corvair, such as an early 6 
cylinder Corvette or a Nash.  Since these were normally aspirated cars, their carbs 
came from the factory with the vacuum advance port already correctly drilled 
and tapped for an external connection.  At the last CORSA Convention, a flea 
market vendor was selling a bunch of YH carbs and I found (and bought) the only 
one of them that had this connection so I knew it wasn't from a Corvair.  Or 
you could try an eBay search for a non-Corvair YH carb.
    An easier way is to simply buy Dale's vacuum advance/pressure retard 
setup and add Ray Sedman's parts that disable the vacuum advance at idle, thereby 
correctly mimicking the action of the carb's vacuum port.  Ray's available at 
american-pi.com
    Incidentally, further details about this are in my Turbocharging chapter 
of the "Corvair Basics" book available from CORSA or your local Corvair club 
for $20.
    Regards,
    Frank "if it don't go, boost it" Burkhard
    
In a message dated 4/16/04 12:25:03 AM Eastern Daylight Time, 
UltraMonzaWest@aol.com writes:
The STOCK  Turbo distributor has NO  Mechanical advance until approx. 
3600rpm.....so the book calls for 24 BTDC.

Make sure the hose is connected to "Ported"  vacume.......Stock YH's can be 
drilled to get it..

Right Smitty???  gg

Matt