Close ratio? or not?

[eric]

      Hello all,
          I'm looking for advice as to whether l should search for a close ratio box, or go with an available
    R.G.S. box.The Jota l purchased, had the chain snap, which destroyed the box and ventilated the
    crankcase, its all been welded up now, but a decision has to be made soon, l have a 180 Mirage, a
    120SFC1000, a 750, so l would like the Jota 'experience' is the close ratio box that difficult to acquire?
    is it all that different to an RGS box?By the way it's '82 Jota, therefore a 120.
              t.i.a. eric
     

 

[bob]

Eric , I think the 120 Jota is the only Jota to have a special set of ratios as standard .
On 180 Jotas close ratio clusters were only available [I believe] as a retro fit racing accessory.
The 120 Jota doesn't have a true close ratio box , but I think it has a taller first gear [I might be wrong about this so hopefully somebody will correct any errors] The 120 Jota 'box is a nice unit , the RGS motor in my spaceframe had been fitted with a 120 Jota box by Phil Todd and it worked well on the track.
Finding a 120 Jota box will be hard so you might find an RGS box is the only option. I don't think it will make a great deal of difference on the road and might even be better in some traffic circumstances.

 

[phil37]

Hi Eric - A CR box is a pain in the arse on the road - even on short duration racing where the starts are so important - it's not a good idea. a well sorted triple will easily have tons of useable torque making the CR box superfluous - Regards - Phil

 

[eric]

        Thanks gents, just the kind of information l wanted.

                eric

 

[jotacorsa]

the jota 120 box is peculiar to that model
and is only considered a close ratio box compared to the RGS
it uses the same first gear ratio as a 750 or 3C
and the same 2nd gear ratio as the '68 GT
there remaining ratios are shared with the 750/1000
however the component parts of the 120 box are not the same as the 180 box

a RGS box is a direct interchange into the jota 120

there are a handful of 120 racers looking for the jota 120 mainshaft and 2nd/3rd gear set
not easy to find

 

[sfcpiet]

Eric,

If your Jota 120 mainshaft is still OK and you decide to fit another gearbox, I'd be very interested in buying/trading!

piet

 

[eric]

      I'll take a peek, and let you know. Excellent advice gents, thank you.

                  eric