F20/F28 Speedo Drive

[Anthony]

Does anyone know if these are identical.
I've purchased a mechanical F28 box but it's missing the speedo drive. Assumed i'd be able to use the one from the F20 but i'm not convinced it's a perfect fit. Does anyone know for deffinate or know if the part numbers are the same?

Cheers

[Harvey]

Re: F20/F28 Speedo Drive

No they are different. The F28 diff ring is blue and the F20 diff ring is black. The F20 diff ring has 26 teeth and uses a speedo drive with 13 teeth. Not sure about the number of teeth on the F28 diff ring but I do know it uses a speedo drive with 15 teeth.

If your question is will the F20 diff ring fit into the F28 box then the answer is yes it will.

F20 diff ring part number is 90125064.

[Anthony]

Re: F20/F28 Speedo Drive

Cheers.
Thinking about it, the box came from a cav gsi, which had been converted to c20let. The box had been converted to 2wd and fitted with a quaife, so i'd like to assume it was also fitted with the correct f20 gubbins at the same time. (so my f20 speedo drive should be ok)
Will have to have another look, but if still has the blue f28 diff ring, it's a case of opening up the box i guess :-(
Regards

[Anthony]

Re: F20/F28 Speedo Drive

No they are different. The F28 diff ring is blue and the F20 diff ring is black. The F20 diff ring has 26 teeth and uses a speedo drive with 13 teeth. Not sure about the number of teeth on the F28 diff ring but I do know it uses a speedo drive with 15 teeth.

If your question is will the F20 diff ring fit into the F28 box then the answer is yes it will.

F20 diff ring part number is 90125064.

Right, looking into the box, it appears to still have the blue f28 diff ring. If i just fit the f28 speedo drive, how far out are the readings on the digi dash going to be?
I'm not overly fussed as its a track car and can't be arced to removed the gearbox again and split it.
Also, anyone know if the f28 speedo drive can be purchased new from vauxhall/autovaux please?

Cheers

[Jags C20LET]

Re: F20/F28 Speedo Drive

Mine, as fitted originally, was an f28 with all the cali gears displayed the right numbers when flicked to kmh. So doing 100 mph road speed, the speedo showed 100kmh or 62mph

[a16vom]

Re: F20/F28 Speedo Drive

Yes I also did this many years ago, flicked it over to kph and it was close enough

[Belmont turbo]

Re: F20/F28 Speedo Drive

Mine, as fitted originally, was an f28 with all the cali gears displayed the right numbers when flicked to kmh. So doing 100 mph road speed, the speedo showed 100kmh or 62mph

yep used to run mine like this to before i fitted the atb

[Anthony]

Re: F20/F28 Speedo Drive

Cheers guys, thats good to know that i can just switch the digi dash to kph and it'll be close enough.....

So, anyone know if you can still get the f28 speedo drives new? Or anyone got one sitting about?

Regards