<VV> Frank Gets Corrected Re: Vacuum Advance? Re: custom distributor curve?
FrankCB at aol.com
FrankCB at aol.com
Fri Feb 22 23:46:21 EST 2013
I was just "checking" to see if you were paying attention!!!<GGGG> If
you believe THAT I have a bridge in Brooklyn I'd like to sell you!<GGG>
Seriously, YOU ARE CORRECT, Bob. With the stock turbo setup, if you
are getting boost at ANY rpm then it will retard the timing to LESS than the
base timing which is supposed to be 24 deg. BTDC (for 65 & 66 180
engines). However, if you are OVER 4000 rpm, then you'll be getting some
MECHANICAL advance as well which will increase the timing ABOVE 24 deg. to be
reduced by whatever the pressure retard subtracts. So below 4000 rpm, any boost
will RETARD the timing. Above 4000 rpm the mechanical advance will
INCREASE the timing while at the SAME time, any boost will RETARD the timing. I
hope I have this right now.<GGGG>
I guess you guys driving out West can get boost at 2000 rpm much more
easily than those of us driving in the "cityfied" areas of the NorthEast.
Thanks for the correction, Bob
Frank "the other one" Burkhard
In a message dated 2/22/2013 9:14:43 P.M. Eastern Standard Time,
BobHelt at aol.com writes:
NO NO! The retard will work at low rpms as long as there is minimal boost.
Boost starts around 2000rpm. Frank, look at the 65 Shop Manual page 6Y-16
fig 11. Pressure retard retards spark to below static setting.
In a message dated 2/22/2013 4:56:03 P.M. US Mountain Standard Time,
robertkhenry at bellsouth.net writes:
Consider the completely stock turbo Corvair that comes with NO vacuum
advance and only has pressure ignition RETARD that works at rpms ABOVE
(for the 1965 and 66 models). Driving these cars in traffic means using a
CONSTANT FIXED ignition timing (24 degrees BTDC) until you get above 4000
rpm AND achieve some boost
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