We are currently running an Escort in Tarmac events and are currently changing diffs to 3.6:1 in the front (basically standard ratio) and 4.1:1 in the rear. We have new gears and morse chain for the transfer box to get a 1:1.148 ratio between front and rear but the ratio between the two diffs is 1:1.138. Obviously this small mismatch will cause the viscous centre work a bit. Does anyone know whether this amount of "slip" in the viscous is a problem, it seems to me it only a bit over 1% so should be ok but some knowledge would be good.

 

Try asking Bara motorsport

 

I think bara can do you a modded viscous that will accept the different ratios. But on a standard viscous with different ratio diffs it wont last long at all. Thats based on my experience/knowledge of the xr4x4's and people swapping diffs ratios and having disasters as they dont realise different models have different ratios

 

the diff will last a little while at that sort of % but not as long as you may think

on the other hand, if it's properl gravely stuff and it's going to get a pounding then it might last longer, but on the tarmac to and from palces it will give up the ghost sooner or later

a good new vc will probably last about 2 or 3 miles with different ratio's front and rear before it's dead