I am looking for the gear ratio of 5th gear in my 98 Honda Civic EX 5 speed manual trans. I am looking to change it out to a lower ratio(lower number) so I can do 80 mph @ 2500 rpm instead of 3500 rpm.

I think the Final drive ratio is approx 4.2 but I am not too sure of that either.

Any valuable information would be appriciated.

 

the 5th gears are pretty close to the same in all d tranny's....not worth time....

final drive is what changes everything

 

if you change it to going 80 and 2,500 rpm, i think your engine is going to bog since at 80, the wind resistance is huge.

 

EX tranny

1- 3.250
2- 1.909
3- 1.250
4- 0.909
5- 0.702
R- 3.153
final- 4.250

if you want higher gearing for the highway, look into a VX or HX tranny.
VX
1- 3.250
2- 1.761
3- 1.066
4- 0.853
5- 0.702
R- 3.153
final- 3.250

HX
1- 3.250
2- 1.782
3- 1.172
4- 0.909
5- 0.702
R- 3.153
final- 3.722

the wind resistance is not too much. My VX ran 2k@60, 2500@75. With 92hp it had no problem holding 90mph for over an hour in 5th and still got ~40mpg doing it. But god did it suck up hills. anything larger than an ant hill and you needed to down shift.

 

get a 92 95 CX tranny
i think its the longest gearing?

 

First of all final drive and 5th gear are NOT one in the same.

The final drive is calculated by using the number of teeth on the pinion shaft and the ring gear, while the 5th gear is calculated by using the number of teeth on the mainshaft 5th gear and countershaft 5th gear.

Having said that the only D series 5th gear that might make any difference would be an old-*** HF 5th, but I don't even think it's possible given that it's a cable tranny.

You'll basically need a 92-95 CX or Vx tranny (they're the exact same), but damn will your car suck to drive because the 1-5 gearing is so far spaced apart and the final drive is 3.25. In other words you'll be giving up closer gearing for better around town acceleration just for the sake of cruising at lower rpm on the highway.

You'd hate a good B-Series VTEC tranny with it's 4.400 final drive and .787 or even .848 5th gear!!!