After watching the video I was caught on one item.
Over inflating the tires. I have over inflated mine and the ride seem a bit more bumpy (I usually drive the car alone or I have 1 extra person with me and I inflated the tires to the pressure stated in the manual for 5 people and full lugage) So it doesnt harm the tires. And I know I will have less traction if I have to break. Anyhow, the bit I got stuck on is this. If you inflate your tires the expand so every turn the tire makes it travels a greater distance. Now your car electronics measures the speed and distance by calculating how many turns the wheels make. So by over inflating your tires your car actually thinks it is going slower. Which would mess up your calculations. If people really are getting better results despite the fact that they should be getting worse results then this really must have a good improvement.
As a result i think that to be able to measure this effect and some others one should use GPS based distance measurement.
The new verison of the iphone os has bluetooth implemented (as in more than just the headset protocol) se this app might be used with the cheaper odb2 bluetooth devices instead of the expensive wlan device that they sell
Yea 3.0 is gonna bring some great things to car computing, but the bt obd2 is definitely one.
Without having done the physics I believe the force of friction will always affect your mileage more than the few centimeters of revolutions you have to do more with over inflated tires. For the extra size in tire to make a difference over the lesser amount of drag you get I don't think it adds up, thats why I think its still advantageous to over-inflate.
However the less friction is always dangerous, keep in mind!
Just to see how much if affects the readins I will try to measure by how much the diameter changes.
Will report back
We also need to know if your RPMs take that into account, and then we need to know how much the diameter affects your MPG. Along with that to make a comparison we need to know how much friction loss you get from inflating to the equivalent amount, and see what the MPG is of that.
My guess is that you will need to over inflate a lot less because of friction than the extra revolutions that occur as a side effect.
I would think that the car computer/ecu can calculate flows etc. However it will be wrong info. Everything displayed on the dash will be slightly wrong (assuming it was correct in the first place) speed odometer mpg.
Taxi drivers in some places install smaller tires so all the equipment in yhe car thinks that the distance travelled is more and the taximeter charges you more.