"nucleus" <rose122550@[EMAIL PROTECTED]
> wrote in message
news:fda31907-0d64-4083-ac0f-4b3f9d7bc9f6@[EMAIL PROTECTED]
> have been driving a 94 and 96 nissan sentra for several years. THE
> 96 CONSISTENTLY AVERAGES OVER 4 MPG GREATER THAT THE 94.
>
> both are stock cars, 4 door, 1.6 liter engines, 4 speed/overdrive
> auto
> transmissions, have same brand & size tires and use the same tire
> pressures, which are adjusted monthly. both cars have almost
> identical
> total mileage. no dragging brakes.
>
> the 96 has a different shaped body and is presumably more
> aerodynamically
> efficient. however, both autos are driven in the same city &
> highway
> mileage
> conditions. the 96 gets better mileage in city driving, than does
> the
> 94.
>
> is there some sensor, that DOES NOT set a computer code, that can
> cause
> the computer to run the 94 engine richer than the 96 engine?
How carefully are you checking your mileage?
Have you checked the odometers against each other? (i.e., Are both
cars showing the same number of miles for a given identical trip?)
The 1996 has slightly higher HP (115 vs 110 for the '94). I assume
this is because the 1996 engine is slightly more efficient (higher
compression ratio, or less internal friction, or more efficient intake
tract). I doubt the difference is worth 4 mpg, but it might be worth
some improvement.
Have you weighed the cars?
The 1996 actually has about 7% greater frontal area, so unless it has
much more aerodynamic shape, there is likely to be little difference
in fuel economy do to aerodynamic drag.
The "combined" EPA estimated mileage for the 1994 was 26 mpg. For the
1996 it was 28 mpg. So I would expect the 1996 to get slightly better
mileage. Given the normal variation in vehicles, and mileage
estimates, I'd say the variation you are seeing between the two cars
is reasonable. The fueleconomy.gov web page also includes MPG
estimates from actual drivers. Unfortunately there were not enough
people posting for cars like yours to draw any reasonable conclusions
(two drivers of 1994 Sentras averaged 30.4 mpg, one driver of a 1996
averaged 38 mpg).
Ed
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