diff ratio

[Catcher]

Hi Ben, I am sure it is 2.3. The guy told me and I did not believe him he showed me the receipt of when he paid to have the diff ratio put in. I spoke to a few diff places about changing it and I was informed that Chev did make a 2.3 ratio.

catcher

[ben]

far out man!! man lucky ya got the trimatic to help out!

must be very economical ay?

ben

[Auda]

I'm putting 3.45:1 (11/38) diffy in mine. The engine is an LD28 diesel with a Jatco 4N71B 4 speed auto which has a 0.6:1 overdrive.
Tyres are 185/70x14

So..
14" x 25.4 = 355.6mm
185 x .7 = 129.5 tyre hight
129.5 + 129.5 + 355.6 = 614.6mm wheel diameter
I dont know how much the tyre squashes with a load so I will say 600mm diameter
600 x 3.14 = 1884mm circumference
1000 / 1.884 = 530 rev/km
530 x 100 (km/h) 53000 revs per hour @ 100km/h
53000 / 60 = 883 wheel rpm @ 100km/h
883 x 3.45 = 3047 drive shaft rpm  @ 100km/h
3047 x 0.6 = 1828 engine rpm @ 100km/h

I think I have got the maths right.
That means that before the overdrive I will be doing 3000 revs at 100k which sounds ok to me.  That will drop to 1800 revs with the overdrive.
The old diffy was 5.286:1 (7/37) which would have been 2700rpm at 100km/h which is what it sounded like.

 One day when I get the driveshaft back in I'll go for a drive and see what its like.
This link http://www.expeditionlandrover.info/enginePwrSpecs.htm gives some usefull info on a few engines for Land Rovers including
LD28 Diesel 6 cyl, no turbo 93 Hp @ 4400rpm 148 ft/lb @ 2000rpm

Auda