Quoting Mike Pittinaro <mechimike@xxxxxxxxx>:
> > If you put overdrive on top of the 2.94 ratio, you
> > have too steep of a gear
> > (like about 2.3). The engine will have trouble
> > hauling the 5400 lbs on
....
>
> It all depends on what you want out of the car, and
> how stock the engine is. A stock 440 makes a lot of
> low end torque, and I don't think a 2.3 final drive
> would be too low. The 80's Imperials used a 2.41
> ratio (I believe, someone correct me if I'm wrong) and
> had only a 318 engine. They also got ~25 mpg on the
> highway. Adding a GV OD unit would definitely help
Well, the 80's Imps also weigh about 1000-1200#s less and have much smaller
tires. Also, the stock 318 as I understand has tiny cam and possibly small
ports, bringing its peak torque at much lower rpm than the stock "low output"
440. Also, my guess is that these cars also have a very low stall converter
with a properly engineered lockup mechanism. Finally, these cars were not
designed with performance in mind.
However, may be I worded my statement wrong. OK, may be the 440 won't have
"problems" hauling the big car around w/ OD. but it wont be much of an
improvement. Its like accelerating mildly from 15-20 mph or climing a
relatively steep hill on 3rd gear (lets say for argument's shake you don't
depress the throttle enough to down shift automatically). Sure the 440 can do
it. But if you down shift to second mannually at the same throttle setting,
your car will accelerate a bit better, and if you watch your tach (assuming you
have one), the rpm will barely increase by downshifting (may be from 1500 will
go to 1600), because the rpm increase due to the lower gear is compensated by
lower converter slippage. I would not pay over $2K for that.
> the gas mileage, and a well-tuned engine could
> conceivably get in the high teens mpg on the highway
> with the OD and the stock 2.94 gears. Even if you
I would like to see that. Using a lockup convetrer on a 60's 440 is somewhat
challenging, because Chrysler never engineered the lockup converters for the
high compression 440s (you may have to find a 78 tranny like my LeBaron, and
try to bief it up in terms of pressure and gears). Also, I do not think you
can use a lockup convetrer with an old transmission prior to lockup converters,
because it does not have the tubing necessary for the lockup activation (but I
may be wrong). I would expect that w/out a lockup converter, the OD in front
of the 2.94 will simply steer up the fluid in the converter and load up the
cooling system with heat, unless you are cruising at 80+ on level road.
Overall of course, Mike and I are in general agreement...
If the GV shifts gears automatically to utilize all 6 gears, that would be super
cool. THe acceleration would be phenomenal, as the shifting will approach that
of a CVT (Continuously Variable Transmision). I would still like to have a
manual over ride in case the eletronics screwed up, which will happen sooner or
later!
D^2
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