RVR & VR4 Auto Box Gearing

[Rockabilly]

This is the RVR & VR4 Auto gearing by me doing a tooth count of both boxes.
The RVR auto has the better gearing of the two boxes going to the rear diff.
RVR front diff divided by it's t/c is 3.305 & the rear is 3.307
VR4 front diff divided by it's t/c is 3.300 & the rear is 3.307
Meaning the viscous coupling in the RVR box has less to compensate for.

Cheers !

 

[to4garret]

so in other words, this means we dont need to run different front/rear tyre sizes when the centre diff is locked?

 

[Rockabilly]

so in other words, this means we dont need to run different front/rear tyre sizes when the centre diff is locked?

An RVR auto is underdriven at the rear by .002 so you can get away with say 42lb rears & 38lb front tyre pres if (Locked)
My RVR is running a VR4 auto diff & switchable t/c, so I'm out by .007 & need to run my staggered tyres. (Locked)
A VR4 or GSR manual is only out by .001 & only needs say 2lb more rear tyre pres if (Locked)
*Note* The VR4 (user manual book) says to run 2lb less tyre pres on rears !! This is to cancell understeer a bit.
If you run a locked centre with lsd rear & non lsd front, steering is ok untill you turn at near full lock.
If you run a locked centre with lsd each end, the steering is a bit harder on you.
An LSD fwd car is a bit harder to steer than a hollow diff fwd car.
I don't like fwd with a hollow diff & that's why I run a front lsd & my switchable t/c setup.
Cheers !