alpalwal

Right now in my 89 240sx I have really short stock gears... the final drive is up around 4.03 I believe.

going 67 on the freeway will put me at about 3k rpms... ka24's have low redlines too.

I spend a lot of time freeway driving. I was curious how much of a mileage improvement I would get from some longer gearing. I was thinking eather a diff with longer legs or a longer 5th gear would make for better mileage.

I'm not trying to spend a bunch of money unless the improvements will be good. Also, how much slower would my car be with a 3.65 final drive or something like that?

Anubis_4_99

i had a turbo 510 with a 4:11 ratio and i got 25ish MPG easy, what kinda mileage are you getting to whine about your gears

and 3K at 60ish MPH is about normal

alpalwal

i get 25ish freeway

Bone1

ALOT depends on the tuner and the VE vs. RPM of the motor under cruise conditons.

Think I'm full ----?

53 mpg and 121 whp from a car that was rated 38 mpg and 85 whp factory.

Oscar

exactly. its not so much your gears, but the way your car is tuned and performs at certain rpms under certain load.

My friend gets 33mpg on the highway with his h22(with h22 tranny). tuned on uber.