It only sounds strange because I have only ever seen statements that it
makes *no* difference. In theory if driving in 4th gives 'x' better mpg
than driving in 3rd, then driving in an OD gear (LH-type anyway) should
give
about half that improvement. Even if you don't actually back off the
throttle in the higher ratio in order to maintain a given speed there are
still fewer sucks, squeezes, bangs and blows per mile with OD engaged which
will result in lower fuel consumption. To have no improvement you would
have to have the throttle depressed *further* in OD, compared to non-OD, to
maintain a given speed. However outside of a laboratory I doubt we would
be
able to accurately measure any difference. Backing off the throttle a
smidgen when you have reached your given cruising speed *does* make a
measurable difference, as do other driving 'techniques' like anticipation
e.g. lifting off the throttle and decelerating for a bit *before* you have
to brake instead of jumping straight from one pedal to the other. Things
like that are why the biggest mpg differences are often down to the driver.
PaulH.
----- Original Message -----
> This will sound strange to a lot of people though - I don't think it
> effects the mileage much.
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