Technical information needed

[Nathan]

Hello,
I am trying to find information of the gear ratios used in Abarth 850 TC, 124 Spyder, and 131.

I need to know gear box ratios and final drive ratios, please.  I have been searching internet to find this and it is very difficult to find.

Thank you Guy for all the very nice pictures!

Also I will like to see any dynomometer readings of these 3 cars if there is any available.  I need this information for a computer simulation.

[Paul vander Heyden]

As far as the gearbox ratios,  the 850TC 4speed close ratios were

3.38  44/13
1.75  35/20
1.20  30/25
1.04  28/27

The five speed simply split some of the gears and could be made with a fifth gear that was slightly over or under drive.  The problem with too large an overdrive ratio is that the gear speeds really get up there.  At 8500 RPM, if you had a 0.890 fifth gear, the gear would be rotating at 9600 RPM.  A good example of this is the Fiat Punto 6speed box where  6th gear is .780.  This means at 9000 RPM the gear is doing a very healthy 11500 RPM.  This would not last long.  Therefore racing gearbox designers always go for a 1:1 final gear, and then adjust for different tracks by changing the lower ratios, or the final drive.

Hope this helps.