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Differenziale autobloccante C514


This self-locking differential (also called "Limited Slip Differential") can fit only to cars equipped with 5 or 6 gears Fiat C514 gearbox; it's available in two models:
-flanged gear ring;
-pasted gear ring.

This device is a helical gears differential: it's able to lock in a progressive way, getting a 35% locking in driving and 25% in engine-braking. Locking rate in engine-braking has been limited in order not to affect ABS correct work during car braking.

How does a self-locking differential work?
First of all, consider the open (=standard) differential in the front drive.


Differential is a device able to share the torque coming from the gearbox in two exactly identical halves, irrespective of wheel speed difference on the same axle.
So, as you can see in the image, said 100 (arbitrary units) the torque coming to the differential, every wheel will receive a torque of 50.

There is another important factor to be taken into account: the grip of the tyres to the ground. Torque can be unloaded to the ground until grip limit of the wheel; this limit is proportional to the load rate acting on the wheel and to the grip factor, which is strictly dependent from soil condition, as well as tyres, obviuously.

So, if one of the wheels of front drive goes over a zone of less grip (i.e. slippery asphalt), or it is low-loaded in driving a fast curve (internal wheel), the torque that this wheel can unload to the ground is reduced because it reaches its slipping limit. Due to the open differential feature said before (mechanism sharing in equal parts the coming torque), the same (low) torque value will go to the other wheel, although it would have a good grip to the ground.

As you can see in the previous picture, said 20 the slipping limit of front left wheel, right wheel cannot do nothing better than unload 20 to the ground. So whole traction of front driveline reduces to 40, significantly less than 100 of previous example.

If we install Prometeo self-locking differential removing the standard one, traction is improved. Let’s see how and how much.

First of all, in condition of good and uniform grip, self-locking differential behaves as an open differential, as shown in the following picture.

If a wheel loses grip, self-locking differential drives an extra torque to the other wheel.
So, whole front driveline torque unloaded to the ground is higher than the torque unloaded by an open differential.
Following picture is very explanatory of the way of working.

The rate of 35% is the best compromise found during plenty of tests made in different conditions. Don’t forget that an excessive locking rate would make the car too understeering in normal drive, with consequent troubles to the driver. On the other hand, a too small locking rate would have reduced self-locking differential advantages, making it substantially unuseful.

With Prometeo Self-Locking differential, you will achieve following important aims:

-in normal drive on solid ground with good grip, nothing different from open differential drive is felt;

-if the ground become slippery (ice, snow, rain), Prometeo Self-Locking Differential significantly improves traction on front wheels.

Driving a car equipped with Prometeo Self-Locking, you'll be able to make a 180° turn at the highest speed, without hearing wheel whistle... Try and trust!

Please, contact us for further information.


It can fit to:
-Fiat: Panda 2WD, 500 (engines 0.9 Twinair, 1.2 Fire, 1.4 Fire, 1.3 Multijet)
-Alfa: Mito (engines 0.9 Twinair, Fire 1.4)
-Other cars equipped with Fiat C514 gearbox

The list above is only indicative; Prometeo is not responsible in the case the product does not fit some particular version of cars listed.

PROMETEO Self-locking Differential for cars C514 equipped with flanged gear ring

PROMETEO Self-locking Differential for cars C514 equipped with pasted gear ring

Kit on sale includes the differential and 2 SKF tapered roller bearings and seals

Differential helical gears


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