Superspec Gearbox

[Al Milton]

Hi All,

 

Quick question, on the MT75 gearbox, what are these?

 

The big red plug is on the passenger side and the little red plug is on the drivers side. One must be the speedo drive.

 

Any enlightenment and tips appreciated.

 

Cheers

Al

[mellors55]

The drivers side is for the speedo drive cable and the passenger side is for the speedo drive gear (to set the speedo drive gear ratio) - you should have recieved this with your kit along with a plug to go on top of the drive gear.

John Mellors

[Guest Tweedy]

Sorry to butt in but I have the MT75 box and my speedo/odometer reads high.Does your reply mean that the ratio can be changed?

Thanks

[Guest chris brown]

Sorry to butt in but I have the MT75 box and my speedo/odometer reads high.Does your reply mean that the ratio can be changed?

Thanks

Yes there are different drive gears. But don’t ask me which colour is which.

[TonySuperSpec]

Yes there are different drive gears. But don’t ask me which colour is which.

 

There are a lot of threads here on this topic.

 

I had a yellow gear on my superspec thats 22 teeth if my memory serves and the speedo was way to high.

 

Typical readings being

 

Speedo Reading / Actual Road Speed(Rollers)

35 / 29

40 / 32

50 / 41

60 / 49

70 / 58

 

 

Just prior to SVA I managed to get a 24 tooth gear and that was a redish colour and that got ne to within SVa standards just..

 

According to Ford there was a 25 tooth gear option on a transit which by calculation would give a 4 mph error across the SVA test range.

 

Apparently the Ford part number for speedo drive is with 25 teeth is F6177330. but my local dealers had no reference to this and the only one they could find was for a late MT75 with an electronic rather than cable take off option.

 

Some other calculations are

Guessing the the margin of error on this test , which is 20% at indicated 35mph, 25% at 40mph, 22% at 50 and 60%, and 20% at 27%, and if the number of teeth on the yellow gear is 22, then a driven gear with 26 teeth should improve things to within approx 1.8mph .

An increase to 27 teeth would take the speedo readin below the actual road speed - no going that far then... SVA fail 100%

 

With the 25 tooth drive available the error sould be around 4 - 5.1 mph.

 

Hope this helps good luck with the fit, I used the 90 degree adapter since trying to get the cable to fit on a superspec without was a 100% failure scratch one cable, Speedy cables recommend the max bend radius on any part of the cable is 5 inchs.

[mellors55]

I also changed mine from the one supplied by RH - I can't remember the colours or part numbers but it now reads a little bit high rather than a very lot high. It was well documented on here (around early 2005)

[Al Milton]

Thanks all, i'll phoning Speedy to get the right angled adapter, good call.

 

I was wondering how the bloody hell the drive will fit, watch for more daft questions

 

Cheers

Al