Ford Fiesta ST180 B6 4.3:1 final drive replacement

Ford Fiesta ST180 EcoBoost 4.3:1 Final Drive
 
Increases Acceleration and 0-60 time.
Direct Stock OE replacement.
Genuine Ford Replacement Parts 
 
Parts supplied
Crown Wheel
Main Output Shaft Pinion
6th Gear Pinion
Main Output Shaft Bearing
 
The Original IB6 type Gearbox has a Final drive ratio which is designed primarily for economy not performance.

by increasing the ratio from the original 3.8:1 to this 4.3:1 version you are effectively taking top speed away from sixth gear and adding acceleration.

Basic Principles

Motorsport transmission specialists world wide have been using this trick for many years to great affect.

The higher the final drive ratio the faster the acceleration through the gears to the terminal speed.

What will the new  ratio do to the top speed ?

With a ratio difference of approx 12-13% that effectively means a lower top speed of 13%.
At 7000 RPM it is approximately 155mph which is a little more realistic and gives the full use of the gearbox.

What will the new ratio do to the acceleration ?

With a shorter ratio and full traction there will be a direct increase in acceleration through every gear.