<VV> Five Speed Transaxles

[Seth Emerson]

I have noted that many new cars reach their highest top speed not in their highest gear. Probably due to torque peak. Top gear is a mileage booster for flat highway driving - -  at legal speeds.<grin>


-----Original Message-----
From: The Corvair Kid via VirtualVairs <virtualvairs at corvair.org>
To: virtualvairs at corvair.org
Sent: Mon, Aug 17, 2020 10:00 am
Subject: Re: <VV> Five Speed Transaxles

As a 5-speed Corvair owner, my perspective is the car is a system. If you change one part of the system, there are likely going to be ripple effects (aka unintended consequences). Fan rotation speed could be an issue, depending on the other elements of the system, so empirical testing is best for any given installation.

One thing of primary consideration is the shape of the torque curve of the engine to which a 5-speed transmission is to be coupled. If it's "peaky" then one needs to be very careful about the 5th gear ratio chosen so that the engine does not strain / "lug" when in overdrive, because that would decrease the usability of that gear and the utility of having it in the first place.

--Kent
Owner of B-W T5 conversion #13

-----Original Message-----
From: VirtualVairs <virtualvairs-bounces at corvair.org> On Behalf Of Cliff Tibbitts via VirtualVairs
Sent: Monday, August 17, 2020 9:01 AM
To: virtualvairs at corvair.org
Subject: <VV> 5 speed transmission cooling

Jay, I would think that cooling would not be an issue.  My 66 with a 140 cools as well at 2200 RPM as it does at 3000.  As for load, your biggest load is accelerating from a dead stop.  Once the car is moving, it takes very little energy to keep it in motion, unless you are climbing a hill, in which case you could simply downshift.
-- 

Cliff Tibbitts
cliff at tibweb.com

-----Original Message-----
From: VirtualVairs <virtualvairs-bounces at corvair.org> On Behalf Of Jay Maechtlen via VirtualVairs
Sent: Sunday, August 16, 2020 9:59 PM
To: Matt <patiomatt at aol.com>; virtualvairs at corvair.org
Subject: Re: <VV> Five Speed Transaxles

On 8/16/2020 12:12 PM, Matt via VirtualVairs wrote:
> Very Interesting Matt!  Didn't know this existed!  I don't know why 
> this isn't publicized more and perhaps kits put together.  Having one 
> or two more overdrive gears to lower the rpms on the highway seems 
> like it would really benefit our cars.  What are the downsides? Todd 
> in TX
>  

How well does the engine cool at higher loads and lower rpms?

Will a stock fan setup cool the motor well enough at 2200 rpm pushing the car 75 mph?

Seems like that would be the main question. I wonder what manifold vacuum you'd be running at that load/rpm?


-- 
Jay Maechtlen
SoCal
'61 2-dr modified w/fiberglass skin,
transverse 3.8 Buick V6 TH440T4 trans

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