VERY Useful, thanks. I have recently discovered that my 328 has what I believe to be a small case diff in it (3.4ish ratio) but sadly still has the original 328 prop. This meant the centre bearing was about 30mm out of position and ripped itself to bits after 3 runs at Norfolk. I am currently trying to work out if I should change back to a 328 diff or if not which prop to get that is 30mm longer on the back section. Any ideas on which prop would do the job as I've just had the diff welded up ? Guy near me is breaking a 320 coupe but TBH it seams a shame to take just the prop from a roadworthy car.
If its a 3.45 ratio then you need the prob from a 320. I wouldn't change back to a 328 diff, 325 is much better. Just get the prob from a 320.
Sweet, thanks for the info. Just spotted a 318/320 prop for sale on fleebay so will go for that for now.
Sounds hopelessly simple but all I did was marked the input flange with a white pen and marked the wheel at 12 o'clock. Then turn the input flange counting turns till the wheel does 1 full rev and thats your ratio.
DrunkBod While turning the wheels full 360 circle, count how many circles the drive shaft does and you will get the differential ratio on any car. You can also do it with the diff on the car and the rear in the air or just the differential on it's own. One more thing. I don't think you can find in UK a 4.44 open diff. Yes it does say for automatic transmission, however from my distant memory on RealOEM this list comes for USA and Japan models only. So I would not buy something on ebay without physically checking just because it came from auto.