Diff ratio swap- need to adjust speedo.

[daicos35]

Team,

I went from a 3.45 to a 3.64 final drive diff.

Speedo is in kph (rhd , australia), and is of course now out of whack.

3 Questions.

1- Is there an E9 / speedo that will work with this ratio - seems the only 3.64 , on an E9, was for USA MPH cars.... (E3 speedos a swap?)
2- Is there an external speedo cable conversion part you can buy?
3- Therefore is only option a hollywood speedos rebuild?


Thanks in advance,

Mike

 

[HB Chris]

Any speedo can be calibrated to match the diff. The speedo itself relies on magnets and odometer on the gears. I went from 3.64 to 3.45 for better highway rpms.

 

[daicos35]

ok, thanks,, i have a 3.64, but a getrag 365/5... not as low as it could be in fifth gear, but an ok compromise..

 

[HB Chris]

With the 3.45 and 265/6 in fifth 3000rpm is 77mph with plenty of oomph left at that rpm.

 

[teahead]

Not cheap, but you can change tires, gears, etc. and it won't matter:

Speedhut Speedbox on stock ‘68 speedometer

Hi everyone, My ‘68 02 tranny was swapped to a 5 speed (240) and with no mechanical speedo cable. So I opted for Speedhut’s Speedbox GPS to mechanical drive speed converter. Bought the unit from North Hollywood speedometer. They fixed my broken odometer and cut the speedo cable for speed box to m...

www.bmw2002faq.com

 

[daicos35]

ha, geez, interesting.. 600 AUD, pre install.. I am checking with Hollywood speedo, on the cost of conversion at moment.. but this is a very interesting product