[ferrisworld]

I have a 2003 ZX3 which I guess would have an MTX-75 right? When I drive 55 I get about 35 - 36 mpg regularly, but if I got 65, it drops to as low as 28. I'm wondering if I can put in a taller overdrive gear, and leave all the other gears the same. Maybe something as extreme as 0.5:1 or somewhere around there. Can that be done, and would it help improve gas mileage?

 

[Blackcatn2o]

I have a 2003 ZX3 which I guess would have an MTX-75 right? When I drive 55 I get about 35 - 36 mpg regularly, but if I got 65, it drops to as low as 28. I'm wondering if I can put in a taller overdrive gear, and leave all the other gears the same. Maybe something as extreme as 0.5:1 or somewhere around there. Can that be done, and would it help improve gas mileage?

Whats your RPM at? are you running 4.06 final gear?

 

[honhon]

have you changed, plugs and plug wires ? gave the car a once over to make sure its running in top shape?

 

[ferrisworld]

It runs fine, it's always tended to get between 28 - 32 highway at 65, depending on the highway / city driving mix. I don't know what final drive ratio I have, but my rpm's are at around 2,700 going 65, and just over 2,000 at 55. I'd like to have them at 2,000 at 65, but I don't know if that would be a good idea or not.

 

[BigRed03]

i get that mileage above the speedlimit... check alignment, air filter, plugs, fuel filter, tire pressure. Plus, you live in a more mountainous area, that can have an affect as well.