Alongside our rebuild and repair service, gearbox and differential upgrades are a daily occurrence here at Motion. We offer hundreds of LSD, gearset and final drive ratio options as well as a complete rebuild or repair service. Our specific gearbox and engine build room has immaculately clean surfaces, a hot solvent parts washer and specialist tooling. This enables us to build all our gearboxes as the manufacturer intended – providing reliability and cost efficiency over a replacement and the risk of buying an unknown and potentially faulty used unit.

When comparing lap time or speed advantage to money spent, a limited slip differential (LSD) is significantly cost effective to any car. The choice of differential comes down to how you use the car but we’ll try to explain briefly here which should help you in identifying the correct LSD for you.

Helical/ATB differentials are fitted to many factory road cars and do not compromise the day to day driveability or comfort when used for the road. In fact, when used normally you might not even recognise that an ATB differential has been fitted. While they do not provide the same amount of lap time reduction and performance as a plated unit, they are completely fit and forget with no maintenance required. This is our most popular upgrade for customers that use their car on both road and track.

Plate differentials are far superior at limiting the slip between driven wheels. They use friction plates and springs to apply a clamp force (preload) with different ramp angles to provide a varying locking force dependant on the amount of slip. This means that they produce more noise (becoming snatchy during low speed cornering) and require regular servicing, making them largely unsuitable for the road. However, if you use the car solely/predominantly on track, then this is the best option in terms of performance.

Gear ratio and final drive changes are a great way of improving straight line speed without the need for any more power. Final drive changes give an overall change to the gearing using only a crown wheel and pinion rather than changing each gear. This results in either an increase in acceleration or top speed depending on whether you shorten or lengthen the ratio. This is the most affordable solution to increasing performance without the need for more power. As it is only an overall change, the RPM drop between gears remains the same.

A short gearset ratio change enables us to bring each gear ratio closer together by changing individual gears. We can then spec the gearbox to ensure the engine is always in the best performance band and uses the entire gear ratio range more efficiently.

For fitting costs please contact us.