2.8 diff

[Ianstonard]

Hi can anyone help I have a 2.8 z3 year 2000
It feels to me as though it runs out of gears and on the motorway it feels like it’s over reving is the a low diff ratio

 

[Lee]

The 2.8 diff is normally a 3.15 ratio diff, there's a sticker on top of it that can confirm this, annoyingly not visible without dropping the diff slightly. Only other option is someone might of changed it, quite common with the 2.8 guys who want M acceleration.

 

[andyglym]

The 2.8 should sit at around 3500rpm at about 70 mph, I think

 

[Andyboy]

With standard wheels - 225/50x16 and the 3.15 ratio diff you'll be doing 70 at 3000 rpm. A few 2.8's will have been relieved of their LSD's and a 1.9 3.45 fitted, or perhaps a 4.1 from a 2.8 Automatic.

You can find the ratio by dividing the number of turns of the pinion into the turns of the driveshafts - both rear brakes need to be completely free.

 

[Ianstonard]

Thank you for your advise