Prometeo Meccanica Self-Locking Differential

Description

Prometeo Meccanica Self-Locking Differential (Fiat Abarth 500)

Like every sports car with front-wheel drive, the Abarth 500 (or Abarth 595) may suffer low traction due to the high torque unloading to the tires. This situation usually happens in corner exiting where the internal wheel is partially unloaded by current weight. When this happens one wheel is able to unload more torque to the ground than the other one causing an imbalance in traction.

A free differential is characterized by the fact that it always divides the torque in two identical shares so the maximum torque which can be unloaded to the ground is conditioned by the grip of the less loaded wheel.

The Abarth 500-595 is normally equipped with an electronic device called TTC, which SIMULATES a self-locking differential. When a drive wheel loses grip, the ECU gives an electric pulse to the brake caliper of the slipping wheel. The negative torque added to the wheel allows to mislead the normal (“open”) differential leading to an identical torque amount with that of the higher gripping wheel.

TTC is a considerable and safe system that permits a good control of the vehicle BUT – we insist – it’s not a self-locking differential and it doesn’t guarantee the performance which only a well made self-locking differential can achieve!

If you use your Abarth 50 on track days or you are annoyed by the unpleasant slipping of the internal wheel at every wild corner exit, a real self-locking differential is your solution.

Prometeo Meccanica’s self-locking differential with helical gears (also know as a “Limited Slip Differential”) has been tested on cars with more than 300nm engine torque and it allows asymmetrical torque coming from the engine to the drivetrain. This means that the wheel with more grip will get extra torque in respect to the other (more unloaded wheel).

The locking rate of the Prometeo differential in driving is about 35%. We preferred not to go over this rate because the Abarth 500 or Abarth 595 is, and still remains, a road car.

Helical gear differentials work in a very progressive way and do not generate unpleasant effects during standard driving. The locking rate in engine-brake mode is limited to 25%, so it doesn’t affect the braking and cornering.

It’s very difficult to explain in words the effect achieved by the sensation experienced when you open the throttle after the apex of a curve and don’t feel like the front is going off on a tangent is something unknown for standard front wheel drive differentials.

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