3.73 final drive ratio rear differential £80 (with dimensions)

[tadekk]

I have for sale a rear differential with a 3.73 final drive ratio from an E46. It was sold to me as compatible with an E85/E86, but on FB someone suggested a ~40mm spacer to extend the propshaft might be needed as this is from an E46 316i compact automatic which has “small” diff casing instead of “medium” one.

The casing is approximately 260mm wide, 400mm long and 220mm tall in case anyone can compare to the OEM E85 diff. Worst case scenario, you could rebuild your diff with rack/pinion from this one

Bought on the forum last year from babw but never fitted. Hopefully someone will enjoy it, as a very cost efficient and reversible performance upgrade for most Z4s. To check final drive ratio for your car visit http://www.bokchoys.com/differential/GearRatios.htm

Z4 2.5i E85 roadster manual 3.46
Z4 3.0i E85 roadster manual 3.07
Z4 3.0si E85 roadster manual 3.23
Z4 3.0i N52 E85 roadster manual 3.38
Z4 M3.2 E85 roadster manual 3.62
Z4 2.5i E85 roadster automatic 3.64
Z4 3.0i E85 roadster automatic 3.46
Z4 3.0si E85 roadster automatic 3.64
Z4 3.0i N52 E85 roadster automatic 3.73
Z4 3.0si E86 coupe manual 3.46
Z4 M3.2 E86 coupe manual 3.62
Z4 3.0si E86 coupe automatic 3.64

Good condition, some surface rust only. Mechanism turns freely and all mating surfaces polished up nicely. There is some oil inside, but I would replace it before fitting.

Collection from Basingstoke RG24 or Reading RG2 only due to insane weight

£80 ono

 

[MACK]

Nice liitle upgrade. I've got a 3.64 on mine and it's the best mod I've done

 

[brillomaster]

Indeed, would be such a good mod for a track car, a diff swap just brings the car alive. And still perfectly useable on a cruise.

 

[Snoop D]

Interested in this...

Will it fit an E86 3.0si? And what exactly of a difference would I feel with this diff? I'm not too knowledge on diff ratios so will need to do my research...

Cheers

 

[tadekk]

Will it fit an E86 3.0si? And what exactly of a difference would I feel with this diff? I'm not too knowledge on diff ratios so will need to do my research...

Thanks, I was hoping it would fit straightaway, but apparently a small spacer might be required as it came from a “small” diff car (E46 compact), whereas a Z4 is a “medium” diff one. I have put the casing measurements, maybe someone can compare to OEM diff on Z4.

As for the improvement, if your car was a manual, you would get 7% more torque at given engine revs, at the expense of top speed. Best explanation I have ever seen was here:
[youtube]DHhY_z1bYA4[/youtube]

 

[tadekk]

Bump and price drop, as I need the space please.