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tachikoma valentines

Wow, I suck.

I can't say that I'll post more often, because I probably still won’t.  Sorry.

Google Reader - chibiryuu's shared items does get updated frequently, with stuff I find interesting, so check there for updates if you want to poll for my aliveness.  Also, if you publish a public RSS feed, thank you for making it easy to stalk keep in touch; if you don’t, shame on you for being anti-social.

Anyhow, I was pretty happy to find a graph of RPM over MPH for various gears of a 2006 Civic Si while randomly browsing: its data corroborates my experiences driving my car.

No, I don’t drive up to max RPMs.  (Okay, I did that sometimes, but not very often.  Besides, I’ve never brought 4th gear to max rev: that’s over 100mph!)  It means that I now have numeric quantification for an interesting pattern I’ve noticed:
gear         2000 rpm                3000 rpm
----  -----------------------  ---------------------
1st   14 km/h = 10 km/h + 43%  13 mph = 10 mph + 34%
2nd   22 km/h = 20 km/h + 12%  20 mph = 20 mph +  5%
3rd   31 km/h = 30 km/h +  5%  29 mph = 30 mph -  2%
4th   41 km/h = 40 km/h +  4%  38 mph = 40 mph -  3%
5th   51 km/h = 50 km/h +  4%  48 mph = 50 mph -  3%
6th   73 km/h = 70 km/h +  5%  68 mph = 70 mph -  2%
Rev-matching anything outside of 1st gear is so very simple.  It seemed far too coincidental when I discovered it experimentally, but the numbers back it up.

Notice how the gear ratios get tigher and tigher packed from 1st to 5th, and then there’s that big jump from 5th to 6th?  When I shift by ear (RPM is correlated to pitch of engine noise), that always throws me off.  Basically, shifting by a single gear usually involves a nice-sounding change in pitch — a major third or perfect fifth interval — except for that 5/6 transition, which is a dissonant tritone.


I wonder if you could make a song of it?

I'm sure if you copied over a fraction of the links you pass about daily, it'd serve a filling post.
tachikoma valentines

November 2009

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