[Ryephile]

So I've been noticing something strange. In both the MINI corporate press release and on MINIUSA specifications it advertises different gear ratios for the JCW compared to the Cooper S. The transmission part numbers and descriptions are different, the Cooper S calling for a "GS6-59SG - TBFJ" and part #23008617542 , and the JCW calling for a "GS6-59SG - TBFN" and part #23008617543 . Despite that, I made a little chart and then recorded the observed speeds per gear per RPM, and discovered something unusual. The gear ratios at least in my JCW appear to be identical to the advertised ratios in the Cooper S. Check it out; the differences are pronounced once you see 4th gear and higher.

Trans_ratios_observed by Ryephile, on Flickr

I asked my dealership for clarification, but at this point they're hesitant to help, only verifying there are indeed separate part numbers and essentially discounting my recorded observations. I need the few of you that have an F56 JCW 6MT to take my speed vs. gear vs. RPM chart and verify which ratios you have. With more information we can storm MINI for answers.

Please and thank you!

 

[02fanatic]

That's pretty impressive! I'm afraid I haven't had my car much over 4,500 rpm yet (only 380 miles) so I couldn't match many of your numbers anyway. I'm actually rather easy on my cars, so I'm not a good one to ask.

I have always wondered what the stock JCW gearing is however. I know it's not limited slip, but electronically controlled (like everything else these days!) LOL! I'm too old school. I know all the rear end gearing ratios on my old BMW's, but I'm truly in the dark about this JCW (and maybe that's the way MINI prefers it).

If you know at least what the final drive ratio is please share.

John

 

[derekh929]

THis any help?

http://www.a3ps.at/site/sites/default/files/newsletter/2014/no17/Transmission.pdf

 

[Ryephile]

That's pretty impressive! I'm afraid I haven't had my car much over 4,500 rpm yet (only 380 miles) so I couldn't match many of your numbers anyway. I'm actually rather easy on my cars, so I'm not a good one to ask.

I have always wondered what the stock JCW gearing is however. I know it's not limited slip, but electronically controlled (like everything else these days!) LOL! I'm too old school. I know all the rear end gearing ratios on my old BMW's, but I'm truly in the dark about this JCW (and maybe that's the way MINI prefers it).

If you know at least what the final drive ratio is please share.

John

Just to quickly address this, the engine is already mostly broken-in at the factory, so babying it won't help anything, and only hurts to finish seating the rings. Following BMW's asinine break-in recommendations is a recipe for long term engine oil consumption.

The notable advertised differences between the Cooper S and JCW transmission are in 4th, 5th, and 6th. For example, at 70 MPH, the Cooper S engine is about 2700 RPM, and the JCW is supposed to be 2400 RPM. That's an easily observable difference.

The Cooper S final drive is 3.588 and 3.824, but the individual gear ratios are also different, so what matters is to look at the actual total ratio (gear x final drive = total ratio). The Cooper S 6th gear has a total ratio of 2.713, and the JCW is supposed to have a 6th gear ratio of 2.401.


Here is the link to my spreadsheet on Google Drive. It's shows the tractive force to the contact patch of the advertised ratios and torque curves for the F56 Cooper S and JCW.

 

[Ryephile]

THis any help?

http://www.a3ps.at/site/sites/default/files/newsletter/2014/no17/Transmission.pdf

Possibly, and thank you for the contribution. It does mention the same ratio spread for the Cooper S and Cooper Works, however it was also published way back in September 2014, even earlier than the official unveiling of the JCW model, which was well before the JCW 6MT ever entered series production.



Frankly, I like the ratios in the car, I just want to make sure it's not the wrong part installed.

 

[lawrothegreat]

You could always have a unique JCW, and if it has shorter gear ratios in 4th, 5th and 6th it may officially be the fastest accelerating production MINI in the world! >

I suspect the gear ratios are the same between the Cooper S and JCW, unless it was a completely different transmission, which we know it isn't.

It would be odd to shorten first gear - being front wheel drive, a standard Cooper S will spin up with TC systems off....

Likewise it would be odd to lengthen higher gears; this may be good for fuel economy, but not responsiveness on the road.

I suspect your JCW is entirely normal, and if it isn't then it's actually better.

If it was the wrong box and there were torque handling issues then clearly this would be a warranty issue.

Clearly the observed differences in later gears eradicates any issues between actual road speed and what the speedometer shows. I actually note that there's a slight 1mph difference between my analogue speedometer and the digital readout through my heads up display; an issue noted by others on here.

 

[jimbo83]

some people have too much time on their hands .........

 

[Ryephile]

You could always have a unique JCW, and if it has shorter gear ratios in 4th, 5th and 6th it may officially be the fastest accelerating production MINI in the world! >

I suspect the gear ratios are the same between the Cooper S and JCW, unless it was a completely different transmission, which we know it isn't.

It would be odd to shorten first gear - being front wheel drive, a standard Cooper S will spin up with TC systems off....

Likewise it would be odd to lengthen higher gears; this may be good for fuel economy, but not responsiveness on the road.

I suspect your JCW is entirely normal, and if it isn't then it's actually better.

If it was the wrong box and there were torque handling issues then clearly this would be a warranty issue.

Clearly the observed differences in later gears eradicates any issues between actual road speed and what the speedometer shows. I actually note that there's a slight 1mph difference between my analogue speedometer and the digital readout through my heads up display; an issue noted by others on here.

I agree with your suspicion the ratios are as-intended, however the disparity is in the published ratios, which do not match. Like you said, if the JCW gearbox was strengthened for torque handling, obviously that would be the smart move to get the intended gearbox.

It's unlikely MINI would have different gearbox descriptors and part numbers if indeed they were the same transmission.


@02fanatic could you please take your car for a drive and verify your ratios per my chart?

 

[02fanatic]

I agree with your suspicion the ratios are as-intended, however the disparity is in the published ratios, which do not match. Like you said, if the JCW gearbox was strengthened for torque handling, obviously that would be the smart move to get the intended gearbox.

It's unlikely MINI would have different gearbox descriptors and part numbers if indeed they were the same transmission.


@02fanatic could you please take your car for a drive and verify your ratios per my chart?

Sure, I'll give it a go when I have the time. One thing that is "very" noticeable however is the tremendous torque of this JCW twin-scroll turbo...even when in 6th gear driving moderately it has "immediate" response! I've never had a turbocharged engine before, and one reason I went for the F56 over buying a used R56 JCW was because of this engine!


My only real complaint so far is the clutch position/operation....it's a bit light for my tastes (it grabs low to the floor but seems to have a lot of travel), and my shoe heel always seems to drag on my rubber floor mat...so I just decided to go back to the stock carpet floor mat in hopes that I can operate the clutch easier...I just need to try different seat positions, etc. to get my driving position better aligned I think.


John

 

[Davo56]

May or may not be helpful but have you checked out www.automobil-catalog.com
Looking at your observations they seem to match up exactly with 'S' ratios as I think you suspect.


Cooper S 4th - 18.6/1000rpm on original 16" wheels
5th - 22.7/1000rpm with 3.588 final drive.
6th - 26.8/1000rpm


JCW 4th - 20.5/1000rpm on original 17" wheels
5th - 25.0/1000rpm with 3.824 final drive
6th - 30.1/1000rpm


Don't know how accurate their figures are but those for Cooper S are spot on from what I can remember of mine. Also the figures they quote for JCW Auto are right at 4th - 18.0/100rpm 5th - 24.2/1000rpm 6th - 30.7/1000rpm.


Cheers Dave

 

[Davo56]

Further to above........read your post on NAM and the above JCW figures are for US model which is also the same for Europe. Seems strange that all the published figures are similar yet yours seems to match those for MCS


Must be some UK 6MT owners who can check theirs?????