Technical Seicento Diff swap

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Technical Seicento Diff swap

Feb 12, 2005
Netherlands TielCity
Hi there,

Since a few days I have a Differential from a sei 1.1 (non sporting 1999). That should be a little shorter than a cinq diff. Someone at the forum here told me that it should fit right a way.

Only I was wondering, this diff is a little smaller (I think). How is it possible that the gear tooth are on the right place and depth in de gearbox?

Please help (before I replace it and maybe destroy my gearbox)

Greetzz Dennis
All the gear ratios of the sei en cinq are the same, only the final drive is shorter. 3.5 instead of 3.8. And the gearbox is also from the same type.

A while ago I changed the diff because it was broken. unfortunaly it throw it away. Otherwise I could see the difference.

1108cc non Sporting


1108cc, Sporting

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I did found my old cinq diff so could see the difference between those two diffs. And It is.....just ONE Tooth. 57 for the sei hobby/suite and 58 for the cinq sporting.

Is this right? And should this give me really 13km/h more top speed?
Nope. Your top speed will be (58/57) x old top speed.

If the diff ratio is substantially different, then I'd suggest the pinion in the gearbox that drives the diff has a different number of teeth.

Depending on what diff the pinion is designed to run with, the tooth pitch and angle might not be right. I'd want to change them as a matched pair.

edit: just worked this out with your findings -

At 3.562, the Suite runs a 16 tooth pinion and a 57 tooth spur wheel (3.562 = 57/16)

At 3.867 the Sporting runs a 15 tooth pinion and a 58 tooth spur wheel (3.867 = 58/15)

so if you just change the diff unit and not the pinion, you'll end up with a 57/15 ratio - 3.800
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NOOOOO!!!!!!!! Why me. Nobody could tell me this so I Thought that the diff should be enough :'(

Ah oke that was the number on the diff. The cinq was 15/58 and sei 16/57

Is it possible to change the pinion to? only I don't have that one because It was a little far away from here to drive. And that's the reason I only get the diff bij post

That from 180km/h to 183.17 km/h
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Someone has a broken seicento young gearbox with the code: C526.

Is this the same as a hobby or suite or is it the one with a closed diff housing.
And what are the ratio's of this box. I think it's the gearbox from 2001 or later. so not compatible for a cinq.

I only need the pinion of it but I don't know if its a 16T or 15T.

Greets Dennis
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I did a search on the EPER DVD and this is the new type gearbox for sei's

A few days ago another person mailed me that he probably has a (diff)pinion with 16T

This is the whole out going shaft.

Does this fit in the C514 gearbox or not?

I have a spare C514 but how can I open the gearbox. I allready opened the clutch housing to gearbox but the meganism is stuck. Or do I need to open it from the otherside (endcap) as they say in the manual.


Greetzz Dennis