On Wed, 13 Jan 1999 Aribert_Neumann%MIMCO@magna.on.ca wrote:
> The only advantage to the overdrive with the 3.89 ratio is quicker
> acceleration. For a given road speed the engine rotates at the same rpm
> with a non O/D trans and 3.27 ratio as it does with O/D trans and 3.89
> ratio. I did a lot of highway driving and wanted to lower the engine
> speed.
I looked this up in the workshop manual after Barry's post, because I was
curious. I agree that the primary benefit of the OD/3.89 diff combination
is in quicker acceleration. The difference in top gear engine RPM is
indeed rather slight; 1000 RPM in top gear and a 3.27 diff gets you 20.15
MPH (assuming OE tires), 1000 RPM in OD top and a 3.89 diff gets you
21.15 MPH. Now OD on a 3.27 diff would make for a rather nicer
long-distance, high-speed cruiser, coming it at around 25 MPH for every
1000 RPM in OD top gear.
--Andy
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