Ford Fiesta ST180 EcoBoost Low Ratio 4.3:1 Final Drive

Description

IB6 Shorter Final Drive As seen on the all-new Mk7 ST200 – Pumaspeed

• Increases Acceleration and 0-60 time.
• Direct Stock OE replacement.
• Precision European made Crown Wheel and Pinion

The Original IB6 type Gearbox has a Final drive ratio which is designed primarily for the 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 worldwide have been using this trick for many years to great effect. (So have many Xbox games)
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?
It’s not that difficult to calculate the results and the potential benefits.
Our GTX28 powered cars run to 8000 revs so at approx 25 mph per 1000 revs that’s a whopping 200 mph capability for the gearbox.
Let’s face it 200mph is impossible for this the Fiesta ST so let’s shoot for a more sensible figure.
With a ratio difference of approx 12-13% that effectively means a lower top speed of 13%.
So 8000 revs would now approximate to 170-174 mph and at 7000 revs it’s approx 155mph which is a little more realistic and gives the full use of the gearbox.

What will the new ratio do to the acceleration?
In gear, acceleration is not as easy to qualify, but with a much shorter ratio and full traction, there will be a direct increase in acceleration through every gear.