Technical Gearboxes

[orangewheeledwonder]

Hi.

Does anybody know if the MK2 1108 sporting gearboxes are the same as late MK1 sporting gearboxes on the Seicento?

Cheers

 

[StoneNewt]

They're a bolt for bolt replacement but the Mk2 ratio set is diffrent, I got the impression that 4th & 5th are a little taller on the Mk2 box.

 

[fingers99]

AFAIK, they're identical, except on the Mk2 Abarths (which have lower overall gearing). The ratios will be out there somewhee on the Interweb, if not here.

 

[StoneNewt]

They can't be identical, the rpm drop between 3rd & 4th then 4th & 5th is different going up the box between the Mk1 & Mk2 Sei's. The Mk2 gears seem to be further apart at the top of the box, hence my feeling 4th & 5th are higher. What I worked out with data from my digidash worked was:

Gear	6Sp	Mk2
1st	3.545	3.909
2nd	2.158	2.158
3rd	1.480	1.345
4th	1.121	0.974
5th	0.921	0.766
6th	0.766

 

[fingers99]

Don't get you. He's asking about Mk1 and Mk2 sporting boxes, you're putting up ratios from a 6 speed box?

Why on earth would they change it?

 

[StoneNewt]

Cause I wasn't paying attention to the ratios I was looking at, this is the correct table.

Gear	Mk1	Mk2
1st	3.909	3.909
2nd	2.158	2.158
3rd	1.480	1.345
4th	1.121	0.974
5th	0.829	0.766

Why change it? Because the MPI's engine revs around 500rpm lower than the SPI, so it needs a diffrent ratio set to give you decent performance on the motorway.

 

[orangewheeledwonder]

Sorry for the late reply. MK2 gearbox has totally messed up- i have a mk1 gearbox to hand. the mk1 takes a manual speedo cable but the mk2 a electronic. anyway top change the cable? not to worried about ratios etc as long as it will work...

 

[fingers99]

You may -- never tried it -- simply be able to take the mechanical speedo drive out and replace with the electronic one. It's more than a question of the speedo though -- the power steering (at least) takes readings from the speed sensor.

 

[StoneNewt]

The diff casing is common and that's what you bolt the speedo drive into, the only difference is if the sender is mechanical or electrical. The take off is actually on the output side of the diff so the final drive doesn't change the speedo reading.

 

[orangewheeledwonder]

Sorry... whats that in layman terms lol. i can change the diff casing to swap from a mechanical. speedo to a electronic?

 

[Pep0]

Cause I wasn't paying attention to the ratios I was looking at, this is the correct table.

Gear    Mk1    Mk2
1st    3.909    3.909
2nd    2.158    2.158
3rd    1.480    1.345
4th    1.121    0.974
5th    0.829    0.766

Why change it? Because the MPI's engine revs around 500rpm lower than the SPI, so it needs a diffrent ratio set to give you decent performance on the motorway.

Your tables agree with the Mk1 Suite and Mk1 sporting boxes figures, but the finals were different between the mk1 cars.

You mean the mk2 sportings have the Suite gears, but a sporting final?

Noel

 

[fingers99]

Sorry... whats that in layman terms lol. i can change the diff casing to swap from a mechanical. speedo to a electronic?

Well, not the diff casing, just the drive, I think. Should take a matter of 5 minutes.

 

[StoneNewt]

Your tables agree with the Mk1 Suite and Mk1 sporting boxes figures, but the finals were different between the mk1 cars.

You mean the mk2 sportings have the Suite gears, but a sporting final

Then yes, the final drives were the same for both boxes. The Mk2 Abarth & Shuie use a lower final drive to compensate for the 14" wheels.

Sorry... whats that in layman terms lol. i can change the diff casing to swap from a mechanical. speedo to a electronic?

No, the speedo sender is a bolt for bolt replacement, having the same casing means that they can't be anything but.