Diff ratio

Post Mon Aug 01, 2005 6:53 pm

What diff ratios would be fitted to a 320 Cheers Keith

Post Mon Aug 01, 2005 6:54 pm

4.10 i think

Post Mon Aug 01, 2005 6:55 pm

i agree

Post Mon Aug 01, 2005 7:02 pm

Cheers lads, i was in the process of changing mine for a 3.91Lsd ( thanks Richy ) but had s**t day but did notice the one fitted is a 3.91 no s marking visible ( probably not an LSD )so i'll check to see if it is

Post Mon Aug 01, 2005 7:04 pm

must be 4.10 on the 320i cab then

Post Mon Aug 01, 2005 7:26 pm

I don't think it's the originalas as i was ferreting around underneath i noticed one of the top landing bolts was missing and it appears that the revs don't corrospond with the cars' speed Showing 70 but the car appears to be a lot slower

Post Wed Aug 03, 2005 2:32 am

diff ratio for a 320 manual is 3.64:1 and an auto 3.91:1
4.1:1 was on th 318is i belive and the us spec M3's
however some eurpean 320's came with a 3.45 which is usually found in a 323i with the dog box

Post Wed Aug 03, 2005 9:06 am

keith52 wrote:I don't think it's the originalas as i was ferreting around underneath i noticed one of the top landing bolts was missing and it appears that the revs don't corrospond with the cars' speed Showing 70 but the car appears to be a lot slower

Changing the diff ratio doesn't affect the accuracy of the speedo. The pulses for the speedo are taken after the gears in the diff, and will only be affected by a change in the rolling radius of the tyres.
Speedo innacuracy, (reading low), is effectively a legal requiremnt.