2 Very Random/Stupid Questions/Observations

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New Guy

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I've always wondered about such effects on our driving and other vehicles w/ these options in general.

Like I thought to myself if I look from my left I see I am going far faster by ~2-3MPH whereas the opposite is true from view of the right side.

Also, I've come to wonder, do other people just speed or what? Even in my GT500 back home whenever I go "speed limit" people just pass me and I'm like 'ah hell no, I know for a FACT that I am so much faster' so how are speedometers calibrated etc? Cause I seem to think that for some reason the vehicles I drive are just slow ass tanks, Raptor being obvious but still...

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Big Blue

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1. Do the adjustable pedals, namely the gas pedal, have any effect on throttle response? Think about it, when you move the pedal all the way "up", there's about 4.5" from pedal to floor. When you move the pedal all the way down, there's about 3" pedal to floor. Since at any point of adjustment, there is a varying distance to the floor, does the throttle calibration change?


2. Speedometer readout beyond 60MPH. Next time you're on the highway going say, 75 mph. Look at your speedometer. The needle reads 75MPH from your point of view centered with the gauge cluster. Now move your head to the right so you're looking at the speedometer gauge straight on...it will appear to read 72MPH.

So the question is, in a world where 10 over the speed limit is probably not going to get you pulled over, and 13mph probably will...how is the speedometer calibrated? Is it calibrated to be accurate from the offset driver's view? Or is it most accurate straight on?

The good news is, the further to the right of the speedo you view, the slower it appears you're going after the 12 o'clock position (60mph). So, from your wife's point of view in the passenger's seat, it looks like you're going about 5-6 MPH slower than what you see from the driver's seat.


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FreightTerrain

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The good news is, the further to the right of the speedo you view, the slower it appears you're going after the 12 o'clock position (60mph). So, from your wife's point of view in the passenger's seat, it looks like you're going about 5-6 MPH slower than what you see from the driver's seat.[/QUOTE]

her heads in my lap, so her point of view is probably pretty much the same as mine. cept she cant see the speedo cuz shes lookin down
 

Harblar

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The shift in indicated speed do to viewing angle is called parallax. Since the needle and guage exist in three dimensions, viewing them from different angles will make it appear as though the needle is pointing at different speeds.

That said, I have no idea if the speedo is calibrated at the factory with parallax in mind. (I kind of doubt it is, since, depending on your viewing angle , you're probably only off by a mph one way or the other.)

As someone else said, changing your tire size will effect your displayed speed. A bigger tire will need less revolutions to travel the same distance at a given speed. The 5 mph difference at 70mph isn't constant. The faster you go, the larger the difference you will see. I'm guessing whoever installed your 37's either didn't recalibrate got your vehicles new revs per mile, or didn't use the tires actual diameter to do it (like my dealer did). They reset the factory point on mine which means when I enter a new value in my tuner it's not correct. It took me about 300 miles of 60mph mile marker time trials, 5-6 retunes, and comparing to an iPhone GPS app to get me accurate.

In the end, what I'm getting at is that from my normal viewing angle I Know I'm within .5mph or less of indicated. ;-)
 
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