I'm wondering if someone could clear up for me a question about the gear ratios in the Cooper vs. Cooper S.

On the MINI Brochure is gives the Cooper 5th gear ratio as .85:1 and the Cooper S 6th gear ratio as 1.09:1.

If a Cooper in 5th and a Cooper S in 6th were going at exactly the same speed, would the Cooper or the S be running at higher rpms?

Or is the gear ratio indicative of something else entirely?

I'm afraid this is the first time I've been interested enough in a particular car to dig up all the specs and so on.

 

Yes, the cooper 'S' has an 'under-driven' (less than 1:1) sixth gear whereas a cooper 5th is over-driven ... so if both are in their top gears, the cooper would be turning lower rpm's than the 'S' at the same road speed
... this also assumes that any wheel/tyre size combination has approx. the same diameter ...

 

Hmm. Did they gear it that way because the supercharger kicks in more at high revs or something? Or just to provide the higher torque at higher revs?

 

is this including the final drive gearing ?

I'll answer it for you; NO!

Real top gear ratios (between engine and axle)
MC - 5th, 3.333:1
MCS - 6th, 2.986:1

[data courtesy of MINI2 and cross referenced MINIUSA brochure, calculator courtesy Texas Instruments (model TI-85)]

Cheers, Motor-on with newfound accurate information,
Ryan

 

>>is this including the final drive gearing ?
>>
>>I'll answer it for you; NO!

So, if I want to see what the actual ratio is I multiply the gear ratio by the final drive ratio?

 

yep!

basically the transmission will do an initial gear reduction (which is controllable by shifting) and the part of the differential assembly is the final drive, which is another gear reduction. It is imparative to muliply these two ratios together to obtain overall ratio between input and output (engine and axles)

The Cooper S is a touch more complex, as it uses two sets of final drive ratios, one set of final drive ratios for 1st, 2nd, 5th, and 6th. The second set of final drive ratios are used for 3rd, 4th, and reverse. The reason for this is packaging, which this arrangement, the gears are used more often, but can be packaged to fit in a very small space (in this case, a 6 speed where there is usually a 5 speed)!

 

Which explains the "tall" 2nd gear that everyone talks about, and also why the brochure lists two final drive ratios for the S.

Thanks. I am now slightly more informed, if not necessarily wiser.

 

Well this explains a lot.

I thought the Six-speed in the S was using some kind of gear spliter setup like this but had not found enough info to confirm my thoughts.

Now I know.

 

>>The Cooper S is a touch more complex, as it uses two sets of final drive ratios, one set of final drive ratios for 1st, 2nd, 5th, and 6th. The second set of final drive ratios are used for 3rd, 4th, and reverse.
>>
.. TWO final drive gears!? ... that's some trick! ... please don't take this the wrong way, I have no reason to doubt you, but have you got some documentation? pictures or drawings? I gotta see this! ... the brochure i have (maybe an old one?) only suggests one ...

 

8ball: The 2003 MINI brochure lists two final drive ratios for the MCS, but does not explain anything whatsoever! The MCS uses the same core Getrag 6-speed transmission as the Ford SVT Focus, but with different gear-change linkage (for smoother and shorter throws), and obviously different casings. I don't feel like searching any further, here's a journal I have:

The Stuff: MCS powertrain pdf

Cheers,
Ryan

_________________
Wisdom is not a function of age, but a function of experience.
*Keeper of the CWFAC list*

 

Ryan! thanks for the .pdf file ... I had to dig into the ETK disc too and that was quite a revelation ... I was kinda wondering why the actual final drive ratio was so hard to find in print! The only number I saw long ago put the ratio alot closer to the Coopers' ... ingenious ...

 

>>Hmm. Did they gear it that way because the supercharger kicks in more at high revs or something? Or just to provide the higher torque at higher revs?

FYI--you are confusing turbochargers and superchargers here. Whereas a turbo is driven from exhaust gases, it tends to need some time to "spool up" to provide boost (known as "turbo lag&quot, a supercharger is mechanically connected to the crankshaft (via belt and pulley) and is always "on boost". For this reason, superchargers generally offer better performance at lower RPM's than a turbo.

 

>> The MCS uses the same core Getrag 6-speed transmission as the Ford SVT Focus, but with different gear-change linkage (for smoother and shorter throws), and obviously different casings. I don't feel like searching any further, here's a journal I have:

I thought that we figured that they were two seperate trannies a while ago? Was something found in my absence to further clear up this matter?

Rocketboy_X

 

Rocketboy, you're confusing yourself again.

The supercharger is driven off the crank, has its' own ratio. Two pullies, one on the crankshaft, one on the supercharger. Always driven in proportion to engine speed (duh!).

Transmission, three-layshaft design with two final drive ratios, six speeds. Input from other side of the engine crankshaft, output to differential and subsequent axles.

PLEASE read the powertrain PDF I linked in my above post.

Cheers,
Ryan

 

>>Rocketboy, you're confusing yourself again.

Umm, I didn't post anything about the supercharger.. I'm just wondering if the Focus tranny and the MCS tranny are the same thing? I didn't read the PFD, (i'm at school/in class now...), but is it the same as the engine design PFD?

Rocketboy_X

 

Okay....I am pretty much just getting to know the inside dynamics of motor vehicles, but I was wondering this same question. I have an MC, but the other day I was fortunate to have a loaded MCS to drive all day. It was a great experience. All of my questions were answered, such as, this transmission question. I knew that at 90MPH my MC was turning 4K even. So I simply took the MCS up to 90mph and found out that the tranny was spinning at just under 4K (about 3.9), not much difference. I thought it would be much lower. I did notice a difference in the feel of the throws. The MCS are a little shorter, and were very loose, whereas the MC is a little stiffer. It was a fun day to compare all of the differences, which weren't much.

 

hey Ryan, that extra gear of the MCS isn't really for lower RPM highway cruising. The gears are "spaced" to keep the engine in the powerband better during spirited driving versus the 5-speed.


Rocketboy, it's .pdf, btw and here it is again: MCS powertrain

This article should clear it up for 'ya :smile:

Cheers,
Ryan

 

Thanks for that file. Great info. Sure wish I could see the diagrams that are mentioned but published elsewhere. . ..

Anyone got those?

 

I wish I had those figures for the article too! It would really help for the visual learners.

Cheers,
Ryan