<VV> Overdrive Transmissions

MarK Durham 62vair at gmail.com
Fri Oct 30 15:04:33 EDT 2015

Bob, I hadn't researched the torque curve, with that data what Richard is
proposing is a great idea!
Mark Durham
Hauser, Idaho
On Oct 30, 2015 8:19 AM, <BobHelt at aol.com> wrote:

> May I suggest that Richard has a great idea here. I don't know just how
> his suggestion might work in actual implemetation but the conncept has
> merit.
> All of the LM engines have a torque peak around 2200-2400 rpm (except
> maybe the 140hp and turbo) so what bad effects could possibly arise from
> reving the engine at a lower speed and still be over the torque peak in top
> gear.? For lower speeds, the lower gears would be appropriate. Normal
> crusing at, say, 60 mph would likely drop from around 3000 rpm (way past
> the torque peak) to around 2400 rpm...right at the torque curve peak. Any
> acceleration from that speed would be from max torque. If greater speeds
> are desired then the available engine torque would still be greater than
> without the 5th gear. If you are still worried, just rebuild your engine
> using the 95 hp cam or Clark's OT10 cam that the aircraft boys use to
> obtain max torque under 3000 rpm.
> Bob Helt
> In a message dated 10/30/2015 7:52:51 A.M. US Mountain Standard Time,
> virtualvairs at corvair.org writes:
> Richard, when you were taught that, did they also throw out there that to
> run engines at lower RPM's you also needed to change the torque curve
> through cam timing adjustments and change the internal components of the
> engines, too. Neither of which we have had discussions about and cannot do
> on the Corvair engines, the parts are not available and would be expensive
> to build.

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