<VV> Overdrive Transmissions

[John Beck]

Shifting 1st, 2nd, 4th in the pattern, using similar ratios to a stock 3 
speed, then moving to the third gear position for a slight overdrive 
seems like it would be pretty easy to get used to.  --J.B.

Jim Becker via VirtualVairs wrote:
> If I ignore all the engine discussion, I THINK the original question 
> essentially was whether you could change fourth gear of a Corvair 
> transmission into an overdrive.  The simple answer to that question is 
> no. Fourth is direct drive, yielding a 1:1 ratio by coupling the input 
> and output to each other.  You can add, change, remove gears all day 
> and all it can possibly change is everything but fourth.
>
> There are other options.  However, since the countershaft gears all 
> come together in one piece, any ratio changes will start to get 
> complicated (read as $$$).  To get an overdrive, you could change 
> another gear to run faster than 1:1.  The obvious change would be to 
> make current first into overdrive. There are complications.  Your 
> shift pattern would change.  Going sequentially through the gears 
> would mean going though the current positions 2-3-4-1.  Using an FC 
> transmission might yield some better ratios for 2 and 3 (the new 1 and 
> 2).  There are some complications.  Using the early transmission, you 
> would end up with a non-synchro overdrive.  No matter which 
> transmission you use, you may not be able to make clearance in the 
> case for the extra-large gear on the countershaft.  Messing with first 
> gear ratios will foul up reverse.  It may be easier to change second 
> or third, which avoids both the non-synchro and reverse problems. The 
> synchronizer parts may limit how small you can go on the driven gear.  
> Also, it would make for an even stranger shift pattern.
>
> Overall, you would probably be better off to use an FC transmission 
> and find some 3.08 final drive gears or have a custom ring and pinion 
> made (if you could even find someone to do it).
>
> Jim Becker
>
> -----Original Message----- From: DickR13607--- via VirtualVairs
> Sent: Friday, October 30, 2015 9:37 AM
> To: virtualvairs at corvair.org
> Subject:  Overdrive Transmissions
>
>
> I understand the rpm problem, but, as an engineer whom worked for FoMCo
> for a number of years, I was taught that lower rpm's meant better gas
> mileage and longer engine life.  Also, why have various people spent  
> years
> working on possible 5-speed transmissions for Corvairs?  I thought my  
> idea was
> much less costly.  Would it work?  I don't know, but I  haven't seen 
> anything
> that addresses that question.
>
> Richard Royle
> 66 Corsa Turbo
>
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