bbsf2

I was lookin around and I found these final drive gears out for the protege/protege 5. they are at www.srmotorsports.com/protege.htm what do u guys think about these? Is it really worth the money? The final gear drive is 4.30. lets here some opinons. thanks

arapau

I assume that would give you a lower ratio and close up the gaps between shifts a little bit. Should give you better acceleration, as you can stay in powerband easier, but will rev more on highway. I wish Mazda had made 5th gear higher. I just drove a Civic to LA and was around 500 rpm less at 75 mph. It makes a big difference on comfort, plus running at 85 seems easier.

gcs118

Could someone please explain final drive ratios to me, and reviewing the basics of gearing couldn't hurt either. Thanks fellas.

arapau

The transmission has 5 reduction ratios and a final drive ratio. On rear drive cars, the final drive is the differential in the rear axle. You can change the final drive ratio to a higher numerical factor> from 3.73-1 to 4.11-1, and this would give the engine more leverage to rear wheels> takes more engine revolutions to turn wheels. Changing this final ratio also has the effect of making the transmission ratios closer> you will drop less RPM's between shifts. The major problem with this mod is that our cars are already geared quite low and this would greatly affect drivabilty and gas mileage. This would be a better mod for engines that are producing horsepower at higher RPM and need the lower gears to make up for lack of low end torque. I hope this helps a bit.

bbsf2

so this mod would really be cost effective if your car was a track car. is it really worth it for the street

gcs118

From what arapau explained to me, it sounds better for drag racing than for a track car. Correct me if I'm wrong, but the closer gear ratios allow for quicker shifting, which essentially means faster acceleration, like in a 1/4 mile race. However, because the low end has been upgraded, the top end is smashed, making for poor top speeds (eg bad for running laps). Is this wrong?

arapau

Really depends how long the straights are. There are some other factors. Like if you car gets to the end of quarter mile maxed in 3rd, you might not want to go to a lower final drive as that might require another shift. I had a sand rail that was geared for 100 yard drags- maxed in 2nd at the end.

goldstar

Changing the final drive gear ratio does not make the transmission gear ratios closer. If you go to a lower (numerically higher) final drive ratio, the ratio between the intermediate gears (1st to 2nd; 2nd to 3rd; 3rd to 4th and 4th to 5th) remains the same. Regardless of the final drive ratio, you will still get the same rpm drop when shifting between gears. In order to reduce the rpm drop between gears, you must install a close ratio gear set which is not available for the Protege. Such an installation requires dismantling the entire transmission and replacing all the intermediate gear sets.

For example, close ratio gear sets are often used in road racing motorcycles and cars to maintain the engine rpm as close as possible to the power peak regardless of actual road speed.

02 DX Millenium Red

kc5zom

Lowering your final drive gear will increase acceleration but the engine RPM at a given speed will be higher. It will decrease your fuel economy somewhat.

Raising the ratio will give you improved top speed, and lower RPM in each gear. Better fuel economy but you will accelerate slower.

Basically what I'm saying is that the final drive affects all gears at once, every gear in the box is connected to it. So if you change it, you change your RPM/MPH relationship in every gear (which in a stickshift is fixed, this many RPM = this many MPH).

Most cars in the United States have an overly high final drive, which helps raise our fuel economy because in top gear we cruise further away from redline (lower RPM, less fuel consumed). So there are usually performance gains to be had, but it would be a b-atch to lower the drive in a FWD car, so this mod is usually for the RWD guys (easy to drop a diff and change gearing, so a very popular swap for Mustang and Camaro heads).

toucci

if anything i would want taller gearing because the damn thing is running like 3800 rpm on the freeway! ahh!

kc5zom

To me the spacing is just all wrong. They needed to raise the 5th gear and get the highway RPM down. I would rather downshift to pass than have 4k RPM going 80. The final drive is nice though on the first 4 gears, maybe a bit lower.