Quote:
Originally Posted by bratboy
hey folks, I just joined and this is a first time post. I had a question about manual transmissions. Over the years I've seen more gears pop up in transmissions. Assuming the final drive ratios are the same and the lower and upper gears are the same...is there much fuel savings between a 5 speed and 6 speed manual?
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it really depends on the car
back in the 80's
VW did the Rabitt with the 4 speed and 5 speed (GTi)
in the 4 speed, 4th is a 0.94:1 ratio
in the 5 speed, 4th is a 1.03 and 5th is a .84
many people would say that with that little OD
the 4 speeds will get better fuel economy unless you spend ALOT of your time cruising at highway speeds
the mustangs and Camaros with 5 speeds had a
1:1 4th gear and a .84:1 5th
the 6 speed cars had the same 4th and 5th and added the "double overdrive" of .57:1 for the 6th
this makes a huge difference as long as your engine produces enough torque down low
and you can keep your speed up
my 2005 GTO (400hp/tq stock) got a solid 30mpg if I kept the speed between 70-75mph and don't make any stops
many of the newer economy cars with 6 speed transmissions
just make the gears closer together and the OD is still close to .85:1