[Rocky eunos]

Hey all,

I'm fitting a 6 speed to my mk1, which has a 4.1 diff.

I'm trying to do the maths but it's making my head hurt.... can anyone tell me the correct size speedo gear required to make the speedometer somewhat right?

Thanks
Rocky

 

[indykid]

The speedo is driven from the gearbox output shaft. The number of gears in the box is irrelevant, only the final drive ratio.

Take the mechanical speedo drive out of your 5 speed box and put it in the 6.

 

[Rocky eunos]

Excellent info, thanks very much 😁

 

[Shadowraven]

4.1 with a 6 speed is pretty short. Not too bad NA but with boost it's maybe a little too short.

 

[Zed.]

4.1 with a 6 speed is pretty short. Not too bad NA but with boost it's maybe a little too short.

gearing calculations. | Mighty5s UK MX5 Forum

random bored prarrie canoeposting time, been playing with gearing calculators comparing different gearboxes (5 & 6 speed Mk1 & mk2) so thought I'd share. https://i.imgur.com/WZyIg

mighty5s.com

Mx5 mk1 & mk2 5speed gearbox vs. 6 speed gearbox gear speeds. 4.1:1 final drive & 7500rpm
as you can see, 1st gear is for driving up the side of a house but 2nd-6th are a lovely close-ratio gearkit

Rich.

 

[Shadowraven]

Yeh I know, i've 6 speeds in both my cars, one with a 3.9, and one with a 4.1 and supercharger. Might as well start in 2nd. I will say I much prefer the 6 speed ratio spacing though, it makes a huge difference and really highlights how long 2nd on the 5 speed is

 

[guitaristanime]

Since I live in 2nd gear I'd be fucked lol

 

[Shadowraven]

Since I live in 2nd gear I'd be fucked lol

You only live in it because it's so long it covers 50% of all the available speed you can do in an mx5

 

[guitaristanime]

 

[Rocky eunos]

Mine is almost exclusively an autosolo car, so the closer ratios are exactly what I'm looking for... hopefully stay in 2nd the whole way around 🤣

Anyway no going back to 5 speed as I sheared a bolt for the slave cylinder in the old gearbox 🤣😭

Never mind they cheap and plentiful, not worth the effort to try and remove it.... on that note if anyone wants to collect I will leave it outside the house 🤣

 

[guitaristanime]

Mine is almost exclusively an autosolo car, so the closer ratios are exactly what I'm looking for... hopefully stay in 2nd the whole way around 🤣

Anyway no going back to 5 speed as I sheared a bolt for the slave cylinder in the old gearbox 🤣😭

Never mind they cheap and plentiful, not worth the effort to try and remove it.... on that note if anyone wants to collect I will leave it outside the house 🤣

theres a guy on here who buys 5 speeds for kit cars...

 

[indykid]

theres a guy on here who buys 5 speeds for kit cars...

This dude

No affiliation, no implied credbility, tread carefully....

 

[Zed.]

no going back to 5 speed as I sheared a bolt for the slave cylinder in the old gearbox

easily fixed if you can weld (weld a nut on the stub)

Rich.