"Doggy" Turbos Re: <VV> Turbos and 3.27 gearing

[FrankCB at aol.com]

Bob,
    If it were MY car, I would definitely go with  "taller" gearing, i.e., at 
least 3.27 or even 3.08 (if it can be found).   This would give you lower 
revs for improved (better mileage AND less noise)  highway cruising.  But I guess 
I'm spoiled with the 3.06 axle ratio in my  Trans Sport that goes to an 
OVERALL 2.2 ratio when it shifts into overdrive  gear.  That combination makes 1800 
rpm at 60 mph in sharp contrast to the  Corvair's 3000 rpm at 60 mph.
    If you want to help cure the "dogginess" of your  Spyder just install a 
vacuum advance unit on the distributor as explained in the  Turbocharging 
chapter of the Corvair Basics book.  When I did that years  ago on my 180, I 
noticed an immediate improvement in PART throttle acceleration  (off line AND 
highway driving) as well as a 20+% improvement in gas mileage  on the everyday trip 
back and forth to work.  After all, EVERY  Corvair other than the turbos came 
from GM with vacuum advance installed.
    "Try it, you'll like it"
    Frank "only partially advanced" Burkhard
 
In a message dated 6/17/2006 7:46:12 PM Eastern Standard Time,  
iamrgh at charter.net writes:

Howdy  All, Does anyone have experience with installing 3.27 diff gears vs. 
the  standard 3.55 in an EM (1963) Spyder convertible/coupe?  I have to have  
my differential checked because of a persistent whine while running and have  
the option of changing ratios at this time.  I realize that there may be  lower 
highway revs/noise, better gas mileage and that  boost may come on  earlier 
because the engine is more "loaded" by the taller gearing.   However I am 
concerned that the car (a convertible) may be even "doggier" off  the line than it 
is now. 



Can anyone tell me what has been your  real-life driving experience with this 
setup?  Would you recommend the  setup to anyone else? Any other 
considerations or recommendations while doing  the diff R&R?  Thanks in advance for your 
thoughts and answers.   Bob Hawley (CORSA WMCC member) - 1963 Spyder conv