Technical High ratio gearbox

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Technical High ratio gearbox

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I am thinking about upgrading our MPI Sei Sporting to a 1242 engine. If I do this I would like to fit the gearbox out of a SX.
I hope the larger engine will pull the higher gears without affecting performance.

Does anyone know if it is just the final drive that is higher or all the gears are different? or if anyone has one for sale?
 
ivantate said:
I am thinking about upgrading our MPI Sei Sporting to a 1242 engine. If I do this I would like to fit the gearbox out of a SX.
I hope the larger engine will pull the higher gears without affecting performance.

Does anyone know if it is just the final drive that is higher or all the gears are different? or if anyone has one for sale?

Do you mean a Sei SX? If you do, then the ratios are a little bit longer over the sporting which would mean you may lose a little acceleration but the engine will run at a lower rpm for a given speed, which should turn out to be more economical (y)
As to whether the not the longer ratios are a result of a different FD or totally different gear ratios (or both), I have no idea TBH
 
Differential gears are as follows:

58/15 for Sporting
57/14 for Sporting Abarth and Schumacher edition
57/16 for Suite, S, SX, Young and the rest
 
chaos said:
Do you mean a Sei SX? If you do, then the ratios are a little bit longer over the sporting which would mean you may lose a little acceleration but the engine will run at a lower rpm for a given speed, which should turn out to be more economical (y)
As to whether the not the longer ratios are a result of a different FD or totally different gear ratios (or both), I have no idea TBH

You should be able to hold lower gears for longer though. I've only driven my 899cc Sei, so I don't know how torquey the other engines are, but if the 1.2 has a lot more torque then it may even be a little faster with taller gearing.

There is also a difference between racetrack performance, and performance on public roads. Being able to reach 60mph in 2nd (I don't know whether that would be possible with the SX 'box) can make a significant difference on a 60mph road.
 
ivantate said:
I am thinking about upgrading our MPI Sei Sporting to a 1242 engine. If I do this I would like to fit the gearbox out of a SX.
I hope the larger engine will pull the higher gears without affecting performance.

Does anyone know if it is just the final drive that is higher or all the gears are different? or if anyone has one for sale?
HI similar thread here
https://www.fiatforum.com/showthread.php?t=39784
hope it helps.
 
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