Anonymous

Does anyone know how much speed difference in a viscous coupling input and output starts to give a significant output.

My question is actually relating specifically to a calibra turbo, which uses a VC to send drive to the rear wheels when the front wheels are slipping, but im making the assumption (always dangerous!) that most 4wd VC's will operate at a similar level of slip.

Not after exact figrues, but for example does the slip need to be the front wheels going twice as fast as the rear or similar amounts, or would 5% difference still see a useful amount of torque transfer?

Jamz

I always wondered the same for the Pulsar, wouldn't it be determined by the viscosity(sp?) of the fluid ?

Anonymous

Yes, that and the configuration of the plates.

The reason im asking is i want to impement traction control so that the front (permenantly driven) wheels dont ever massively spin as this obviously will reduce acceleration as less torque will act on the tarmac from the tyres.

Most traction control systems work at about 5-10% slip, so my worry is that if i stop the wheels spinning more than say 10% it might stop the VC from transferring power to the rear, and obvioulsy if i do that then the car will get slower not faster!