|
It is ridiculous when you consider the old 76 280Z I drove many years ago. I put a later 5 speed in the car with the stock 3.54 differential. Later I replaced the diff with a 3.90.
With the 3.54 it would do close to 90 MPH at 3k rpm. The later 3.90 gave it 30,60,90,120,150 top speeds in each gear, calculated at max RPM.
The Altima in top gear is very close to the same revs per mile as the Z was with the original 3.54 differential, and very close to the 94 VX. Any car that is taching 3k at 60 in top gear should have at least another .75 to 1 overdrive top gear or even greater.
Maybe you would have to downshift climbing a grade with a full load, but that seems like a limp excuse to not give you good highway economy, especially with a 6 speed transmission. You could have 30,60,90,120,150,180 and be at half red line at 90 MPH.
With the higher power of today's engines it would sure be nice to think the car companies don't consider us to be so stupid we can't use a lower gear when the loads are too high for a really tall top gear.
Just using a different differential ratio or gear sets is about as simple as you can get when you do it building the car.
That's how they are getting decent mileage out of the new high performance cars. I guess they forgot we dropped the 55 MPH speed limit.
In fact my old 59 Corvette with a .308 diff was close to the same revs per mile as the rest of them, something like 2100 at 60.
regards
Mech
|