25 replies to this topic

[nicklouse]

Yes measuring rotation of engine versus wheel rotation in each gear will help you ID what gear set you have  and also what final drive as all gearboxes have 1:1 4th gear

 

write it all down and share if you can’t do the math someone will help out.

 

oh I would do it on flat ground and mark a tyre and ground at the start. Then also mark the end of one wheel rotation. Then you don’t really need to watch it. And you can concentrate on the engine rotations.

[gav]

 

 

 

 

The engine is a 1430cc so there is quite a lot of torque.

I quite like the idea of swapping first gear for a taller ratio rather than swapping the whole gear set.

I'm not sure which 4 synchro gear sets would fit the A+ box.

I guess the Cooper S gear set is out because my gearbox would have A+ flat top profile gears?

 

How did you find cruising and top end speed ?

As sets, all of the 4 Synchro sets will fit in an A+ Case, even a Turbo one.

A change of 1st Gear Ratio would actually mean a complete Set change, while all '1st Gear' in all sets were the same Cog, the Laygears, 2nd and 3rd Gears and Input Gears are all different.
 

 

 

The top end speed was good and i had enough power to 'duke it out' on dual carriageways with bigger cars.  This was around 20 years ago though.

 

Are there many helical gearsets available with a taller first gear?

 

I see Mini Spares have an Evolution kit, have you tried it?

 

I just noticed Guessworks lists some of his own gear kits in the ratio calculator.

 

 

It does sound like your final drive ratio is fine, but you may need a closer gear ratio set and / or a taller final drive.
 

I haven't tried MS's Evo set or much aftermarket stuff.

This is a table I put together a few years back covering the factory gearsets, by part number, what goes with which and the ratios they give;-

 

 

Mind if I save this? Very handy.

[coopertaz]

which S gearkit?  you dont want a 3 synchro one....   i asume you meank the mark3 "1040" gear kit.

 

 

you can get parts to swap the turbo box to those ratios, by just swaping the laygear, and 1st motion shaft, (i seem to recall some MPI's had this?)

 

turbo final drive was 3.2, so you could up that to a 3.1, I think the MPI 2.9 would be a bit tall personaly

wasn't mpi 2.76? i know 2.95 is hle as that is what i had. you don't state what size wheels you have ( cue comments on same rolling radius but does make a difference) found sccr clubman set to have taller first gear and reduced gap between 2nd and 3rd (also like the sound, personal opinion) your spec should have enough torque to drive turbo 3.2FD fine but even with 3.44FD first is longer. also quiet for motorway as not driving laygear in fourth. whatever you chose don't forget speedo drives!!

[Spider]

 

 

 

Mind if I save this? Very handy.

 

 

Sure

[ac427]

So assuming i have the 4:1 first gear, what would i have to change to get first gear to a 3.30 or 3.64 ratio?

Would it be:
A. The first and the layshaft
B. The first gear, layshaft and first motion shaft?
C. Just give it up and build a straight cut box?

Edited by ac427, 04 May 2022 - 07:55 PM.

[nicklouse]

So assuming i have the 4:1 first gear, what would i have to change to get first gear to a 3.30 or 3.64 ratio?

Would it be:
A. The first and the layshaft
B. The first gear, layshaft and first motion shaft?

You should have a 3.64 in it IF it is a turbo box.

 

work out what you have or just pull it and sort it.

[ac427]

So assuming i have the 4:1 first gear, what would i have to change to get first gear to a 3.30 or 3.64 ratio?

Would it be:
A. The first and the layshaft
B. The first gear, layshaft and first motion shaft?

You should have a 3.64 in it IF it is a turbo box.

work out what you have or just pull it and sort it.

Agreed but i would still like to know what is actually required to alter the first gear ratio alone?

I'm sure others would like to know too.

Edited by ac427, 04 May 2022 - 08:18 PM.

[KTS]

The gearbox design prevents just one gear ratio being changed

First,second and third are all set by the laygear that's being used

[ac427]

The gearbox design prevents just one gear ratio being changed

First,second and third are all set by the laygear that's being used

Thank very much KTS.

[Spider]

So assuming i have the 4:1 first gear, what would i have to change to get first gear to a 3.30 or 3.64 ratio?

Would it be:
A. The first and the layshaft
B. The first gear, layshaft and first motion shaft?
C. Just give it up and build a straight cut box?

 

A change of 1st Gear Ratio would actually mean a complete Set change, while all '1st Gear' in all sets were the same Cog, the Laygears, 2nd and 3rd Gears and Input Gears are all different.

 

Recapping here, it would mean a change of all gears except for 1st and Reverse.

Put another way, you'd need a 1st Motion Shaft (to suit the gearset you are wanting to fit), Laygear, 2nd and 3rd gears.

The ONLY sets you don't need to change all these with is when swapping between the 'Standard' (Pre A+) Ratios and the Cooper S Set. In that case, it's only a change of 1st Motion and Laygears.
 

[ac427]

So assuming i have the 4:1 first gear, what would i have to change to get first gear to a 3.30 or 3.64 ratio?

Would it be:
A. The first and the layshaft
B. The first gear, layshaft and first motion shaft?
C. Just give it up and build a straight cut box?

 

A change of 1st Gear Ratio would actually mean a complete Set change, while all '1st Gear' in all sets were the same Cog, the Laygears, 2nd and 3rd Gears and Input Gears are all different.

 
Recapping here, it would mean a change of all gears except for 1st and Reverse.

Put another way, you'd need a 1st Motion Shaft (to suit the gearset you are wanting to fit), Laygear, 2nd and 3rd gears.

The ONLY sets you don't need to change all these with is when swapping between the 'Standard' (Pre A+) Ratios and the Cooper S Set. In that case, it's only a change of 1st Motion and Laygears.

Thanks very much Spider.