In a message dated 97-09-16 02:52:35 EDT, GDWF22A(at)prodigy.com (MR RICHARD T
TRENK SR) writes in response to Tony Leeming:
>I may be mis-reading your last comment in which you seem to state that you
>"toured with the 3.89 gears and have added a OD unit to THOSE gears??? "
>This would raise the mph/rpm data to where 1000 rpm would make about 24mph.
>Carrying this data out to your "cruise speeds of 3000-3500 rpm, this means
>you cruise I-5 at 72-84 mph .
>You also mention that the car has nice low rpm response in OD !
>
>I too would like OD for highway touring use, but would want the proper gear
>ratio that OD works best at. I simply have a hard time seeing how a stock
>engine could have nice low rpm response when pulling 3.11:1 drive ratio you
>seem to now have.
>
> In Colo. we have long mt. passes where a car may be on an upgrade for 45
>minutes or more. In such sustained strain, you would want to shift out of
>OD to let the engine "breath" and reduce bearing stress etc. etc.
>High revs DO NOT harm a normal engine, particularly small size import
>engines which can easily spin a 4000-4500 (and higher) all day long without
>any abnormal wear. These same small engines get wrecked or at least have
>early overhauls is they are continually made to work hard at lower rpm.
>I trust you will consider all this and perhaps avoid OD on hills at least.
>
>
Tony L. forgot to mention that he lives on an island thats so tiny that by
the time he gets the Alpine up to OD speed, its time to stop and turn around
again.
I'm planning to eventually install an OD in my Series V once its rebuilt.
The objective is 'effortless' highway cruising capability. The possibility
of twisted shafts and the loss of five HP are not looked forward to, but the
alternative today, even with 3.89 gears, is to have to continuously run 4500+
rpm's just to keep up with freeway traffic. Particularly if you run a wider,
lower profile tire. I agree that the Alpine engine (the 1725 at least) is
capable of maintaining these rpm's without damage, as my last engine was good
for about 130K, at least half of it freeway. I guess its a matter of driver
comfort, not having to listen to extended periods of buzzy high rpm racket,
and the ability to take advantage of those highways where high speeds are
still possible, without redlining.
BTW, Series III's all came with 3.89's, with or without OD.
Dick Sanders
P.S. Another partial alternative to OD as mentioned before is to install
3.70 gears, available new from Sunbeam Specialties or, if you can find one,
from an Alpine GT fastback (automatic only).
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