"Big Blue" <aclaritan@gmail.com> wrote in message
news:9fj6k2teeiapsgr7hvo0las8d7803bi402@4ax.com...[color=blue]
>
> I've been suspicious for some time, but now I've gone out to prove it.
> I always though the speedometers on new cars are too fast than actual
> speed, but now I've gone out and prove it.
>
> I took my 1990 Corolla and drive 65 mph and have my wife drive our new
> Camry 2007 SE V6 behind me. We talk over walkie-talkie. She told me
> when my Corolla says 65 it says 70 mph on her Camry. Then I speed up
> to 70 mph and the Camry, matching my speed, says 75-77mph. I slow
> down to 50 mph and the Camry says 55 mph.
>
> I did the same test drive on my 2000 Maxima, same result (Maxima
> faster than Corolla at "same" speed)
>
> Interesting huh?
>[/color]
No. Not interesting at all. Sorry.
You are comparing a beat up old base-model car with a brand new
top-of-the-line car. In one, they throw a pile of pieces together and
proclaim, "it works, let's sell it," and in the other they go to great pains
to make sure the parts all work together just the way a driver might want
them to. The approach to building the car makes a big difference in what the
car tells you. And, if the Corolla came with tiny little tires, and somebody
along the ownership line opted for a larger tire, then the speedo would be
reading slow -- which is what yours is doing.
I'd give odds that the new cars are MUCH more accurate than your Corolla.
The actual way to test this is to set the cruise control and use a stopwatch
to time how long it takes to go a measured mile. Mile markers are placed at
half-mile intervals along the shoulder of the highway for this purpose.
(Well, the purpose they are there might be different, but they can be used
for this purpose.) As you pass a mile marker with the cruise set, click the
stop watch and keep your eyes peeled for the next marker at which point you
stop the watch.
Divide 3600 by the time it takes to go a mile, and the result is your actual
speed.
3600 / 65 = 55mph
3600 / 60 = 60mph
3600 / 51 = 70mph
3600 / 45 = 80mph
Due to the magic of mathematics, you can divide 3600 by your speed to
calculate the location of the next mile marker. Since you know that if you
pass the markers at 51 second intervals, then you are going 70. If you are
going 70, then you can calculate that the mile marker will appear 51 seconds
after the previous marker. If a marker is missing, the next marker should
appear after about 102 seconds. (Actually, 70 takes 51.4 seconds, so the
next marker after the missing one should come at closer to 103 seconds.)
I challenge you to run this test in your Corolla and your Camry and see
which speedo is more accurate. I suspect you will find that the Camry is
going 80 on the speedo, it is really doing about 77 on the ground. Given the
numbers you cited, the Corolla at 80 should be doing about 83 on the ground.
(I suggest you run the test at the legal speed limit, but your tolerance for
pain will dictate what speed(s) you actually test.) The cars that I own and
have tested are doing an actual 78.5 when the speedo reads 80.
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