I'm away from my owner's manual right now, and I'm trying to find out what the ratios are for 1st and 2nd gear on the 2005/2006 six-speed transmission. I've tried the search feature, and found a lot of discussion about the ratio changes for 2005, but not the actual ratios themselves.

The reason I'm curious is that when I'm autocrossing, I generally stay in 2nd gear throughout the entire course. Looking at the data logfiles from my last event, the highest engine speed I recorded during any of my runs was 5690 RPM.

I'd like to find out if I could have run the course in 1st gear without hitting the rev limiter, but I need to know the 1st and 2nd gear ratios.

There's another MINI owner in our club that routinely uses 1st gear for the autocross courses, but he has one of the older MINIs with the higher (numerically lower) gear ratios, so he can go faster than I can in first gear without hitting the rev limiter.

 

Check out the following ...

http://www.mini2.com/forum/faq.php?f...speed_in_gears

 

Thanks for the link - it looks like 5690rpm in 2nd gear would put me at 9330rpm in first gear, for the same road speed.

So much for doing the entire run in 1st.

 

total dork/tech ignorant here... how do you read that gear chart?

 

The gear chart is listing "combined ratios", which is a combination of the gear ratio in the transmission AND the final drive ratios. The combined ratio gives you the relationship between engine RPM and wheel RPM. So, for my car, 1st gear is 12.789:1, and 2nd gear is 7.793:1.

That means that when I was turning 5690 engine RPM in 2nd gear, the wheels were turning 730 RPM (5690/7.793).

Now, to figure out what the engine RPM would be in 1st gear for the same wheel speed, I multiply the wheel speed by the combined ratio for 1st gear, and I get 9337 RPM (730 X 12.789).

This means that if I used 1st gear instead of 2nd gear for the run, and wanted to keep the maximum wheel speed the same, I would have to run the engine up to 9337 RPM, which is *way* beyond the safe operating limits for my engine. I think the factory rev limiter kicks in at 6800.

 

*7100-ish. The actual limit AFAIK is 7k rpm but according to the tach it doesn't seem to shut ya down till another 100.