Subaru Forester: Speed Demon!

I finally figured out why the Forester feels so slow:

Subaru Forester - speedometer
Subaru Forester – speedometer

Here in the Northeast US, the maximum legal speed anywhere is 65 mph, less than half-scale, and typical around-town speeds hit 40 mph, barely 1/4 of full scale.

For all practical purposes, that needle barely moves during our usual trips.

I like analog gauges to represent smoothly varying quantities that you must read at a glance, but a big digital display would actually be more useful than that thing.

A 150 mph speedometer scale makes no sense in what’s basically a shrunken all-wheel-drive SUV, even with minimal off-road capabilities. Yes, perhaps the Forester could hit 150 mph, but why not have the scale top out around, say, 100 mph? Above that, you shouldn’t be paying much attention to the speedo, anyway.

The Sienna’s speedo went to 110 and, to the best of my knowledge, that needle never passed 85 mph, tops. However, ordinary (and legal) driving speeds filled the lower half of the scale, with the highest useful speeds in the next quadrant beyond vertical.

Yes, I know why the speedos sport such absurd numbers. I don’t have to like it.

There’s a servo motor (or some such) driving the needle; calibration has been a simple matter of software for a long, long time.

For whatever it’s worth, the Forester and the Sienna have both tachometers and automatic transmissions, a combination that converts shifting into a spectator sport. The Forester’s continuously variable transmission moves the tach needle in smooth glides, rather than abrupt jumps.

12 thoughts on “Subaru Forester: Speed Demon!

  1. It would be fun to give it a non-linear scale, so it “could’ register up to 150mph, but the resolution would be where you need it. Since that firmware change is probably messy, you could replace the scale with something like this. Won’t make it easier to read, but it might make you smile a bit: http://www.playdota.com/forums/picture.php?albumid=287&pictureid=40003 At least there is one 70mph road near where I live in Virginia.

    1. It gets faster west of the Mississippi. Along the salt flats on I-80 in Utah, it’s been set at 80MPH, though the days I drove it, 75 was the smart and popular choice due to winds. The rest of the way, it was 70 to 75 outside the urban centers on good terrain.

      Some of the wind-prone areas in Wyoming have variable speed limits, so you can see values from 55 to 75 depending on the current weather. It’s handy for the areas that have to be rebuilt every year or two, also.

      I have the older 4 speed automatic, and it’s nice to see the torque convertor lock up, with a promise of better gas mileage. FWIW, the display matched my records within a few percent. I was impressed.

      1. it was 70 to 75 outside the urban centers

        I’ll grant that the prevailing Interstate speeds run around 75, even here, but we surely don’t need a factor of two just for passing, do we?

        Well, OK, I don’t need a factor of two …

    2. A logarithmic speedo scale: I’m sure you can patent that! [grin]

      My speedo pictures would progress upward from sloths to koalas, with maybe a roadrunner extended along the high side of the scale…

  2. I believe Subaru does make a version that will top 100 MPH by quite a bit. Having separate speedometers for that version and yours doubles the number of speedometer heads (and probably other components) at assembly plant, parts warehouses, suppliers, as well as a number of other issues that significantly increase cost and complexity.

    Most modern autos get the speed info from the ABS sensor(s). Probably don’t want to mess with that.

    1. Oh, I’m certain the Forester can get close to 150 mph, despite the Owners Manual warning about the large sail area and alarmingly high center of gravity… so, of course, they must have a speedo to match. [mutter]

      In this day and age, though, Subaru could do a glass cockpit speedo with two sets of numbers and an ersatz analog pointer, but, yeah, a mechanical gauge does have its limitations.

      I bet they could figure out a way to charge an absurd amount of money for different (in my case, fuddy-duddy) speedo scales. After all, I paid for auto-dimming mirrors, so they can surely turn a profit on the speedo.

      Of course, I was the only person who ever asked to get the non-dimming mirrors they replaced, which are now in a box labeled Forester Parts. [grin]

    2. The Forester is an Impreza with a high-top conversion, basically, and some Imprezas are WRX models, so yeah – 150 sounds about right. And the daylight speed limit on I-10 in Texas west of Austin is 80 and you need to be able to do 85-90 to keep from getting creamed, so some users will get over half scale.

      Remember when speedometers were capped at 85 and the 55 mark had to be emphasised? When did that end? About 1990 or so?

      1. Remember when speedometers were capped at 85 and the 55 mark had to be emphasised?

        That would have been right around the time I was biking to work, alternating t-shirts reading ODD and EVEN on the back… [evil grin]

  3. Yes, I know why the speedos sport such absurd numbers. I don’t have to like it.

    You mean something like to prevent the mechanism from being damaged by exceeding its highest possible value? Or more like because everyone tries 160+km/h in Germany at least once? ;)

    1. Nah, because here in America, bigger is better: if their speedo goes to 140 mph, then your speedo must hit 150 mph.

      The firmware behind the needle is (uh, should be) smart enough know when to stop turning the crank; there’s no risk of breaking anything at the high end.

      Another data point: the tach, which is totally useless with an automatic transmission, redlines at 6000 rpm and goes to 8000 rpm. Normal driving runs around 2000 rpm, 1/4 of full scale.

      Makes perfect sense to me … [sigh]

      1. I don’t even know if the “crank” is there. Are those needle drivers geared, and does the actuator have enough oomph to break anything? I’d think it overdesign. The one I’ve seen when I wanted to pick one up at the junkyard to see what’s inside consisted of a direct-drive brushless motor with apparently 9 electric poles per revolution and a viscous damper. You’re 100% on the money that it’s all firmware-driven.

        1. 9 electric poles per revolution and a viscous damper

          They’re definitely motor driven: part of the lamp check involves spinning both needles up to the high stop and back down again.

          Somewhere in the heap, I have a couple of instrument clusters from some random vehicle. Maybe there’s an Arduino project lurking in that box, too. Hmmm…

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