Gear ratios: 2014 Mirage transmissions, 5-spd manual F5MDB & CVT (speed vs RPM chart)

[Daox]

Correct. That is the US trans.

Alright, here is ALL of the trans info on one chart! Including the mythical 'nerd gear' that some of us would like to have (combining the US 5spd with UK final drive).

... and the CVT still spanks the 5 speed for cruising rpms.

[Daox]

I've added another graph to the first page from IchabodCrane's information here:

http://mirageforum.com/forum/showthr...ll=1#post12424

Thanks IchabodCrane!

[foama]

Let me summarize the probably most important points from a European view:


120kmh is the average driven speed on Autobahns and other motorways when not congested or otherwise limited. That just about coincides with the max permitted speed in many other European states.

At 120kmh the European MT model would be running at 3250rpm in 5th, and at 4000rpm in 4th gear. (Total ratio in fifth Euro model: 0.85 x 3.55 =3.0175)

At 120kmh the USA MT model would be running at 3750rpm in 5th, and at 4500rpm in 4th gear.
(Total ratio in fifth US model: 0.804 x 4.055 = 3.26)

I recall my 1997 Suzuki Swift (Metro) which was the 4cyl 1.3l 8V model having a total ratio of 2.66 in fifth gear.

Thanks to MetroMPG for the charts on which this post is based.

My Mirage is 1.0L / MT with 3.55 final ratio.

The more powerful 1.2L with the USA final ratio? I would never in my life consider buying one!

For my personal liking the European gearbox could be another 15% or so taller for the 1.0L, for the 1.2L maybe 20% taller.
The fifth gear of the US modell would be appropriate for both models and make practical sense.
Foama

[DonHoot]

Hey, I did figure out how to save data from Dashcommand, but the file is a huge excel file. So I just did some averages for different speeds.


At:

25 miles per hour - 1260 RPM
55 - 1850 RPM
60 - 2285 RPM
65 - 2468 RPM
70 - 2600 RPM

These are averages of a LOT (hundreds) of data points.

[MetroMPG]

Don, we integrated your numbers into the graphs in post #1:






I suspect IchabodCrane's plot (blue) is lower and smoother because the numbers were gathered experimentally at steady speeds on the same road & conditions, where your figures are averages from varying conditions/loads/grades. Sound right?

[DonHoot]

Yes my data was taken from a highway drive that varies in grade. The actual rpm data swings all over the place as the cruise control adjusts for this. My home is 400 feet higher than my workplace over a 24 mile journey, so I was also going up the whole way home.

Since the transmission replacement work the car just seems "tighter" to me, in other words it just doesn't seem to coast as far in drive. And I think my average mpg is a little less, it seems my fuel log chart has trended down since the new cvt. But it's also colder so it's really hard to tell.

So maybe the combination of new cvt and uphill grade combine for the higher average rpm, but the curves do match fairly closely.

[firegarden]

for manual trany, will be ok to use 75w 90, Royal Purple?

[mitsulorette]

I don,t know if the ,14 and the ,15 trany are the same, but mine is a ,15 and at 100kph (62mph) it is 3000rpm

[mitsulorette]

I don,t know if the ,14 and the ,15 trany are the same, but mine is a ,15 and at 100kph (62mph) it is 3000rpm; it is a manual

[Donut]

I've logged some data from my last trip and plotted the RPM vs Speed (kmh).
The scatter plot nicely shows the 4th and 5th gear bundle together onto two distinct lines.



One can get the slope of either gear as:
4th gear slope 35.92 RPM/kmh
5th gear slope 30.85 RPM/kmh
ratio=1.16 (without proper error analysis...)

The ratio should actually correspond to the gear ratio
.

The two available models have:
US version:
4th - 0.973
5th - 0.804
ratio=1.210

UK version:
4th - 1.027
5th - 0.850
ratio=1.208

The 4% error with respect to the US numbers must be likely related to a poor linear fit, or improper speed calibration.
Or do you have suggestions?

The above measured ratios are robust to assumptions, since effects like wheel diameter and final drive cancel out. I still have calculated the wheel RPM by measuring the wheel diameter from a technical drawing and using the final gear ratio of 4.055 and get 0.815 for the 5th gear ratio.

Note: the circled region shows the markers for coasting in neutral and would possibly dominate the respective graph from our MPG guru 3dplane.