2022 Subaru BRZ - 4.10 vs 4.30 Differential - Highway MPG Test 

Not to mention...if I run 35 psi the centers of the tires wear out faster than the outer sections...on a similar car.

The car is not processing fuel burn based on final drive ratio from the diff.. it's calculating distance covered vs fuel remaining and simultaneously delivering MPG and range. The same applies to installing new tires, or anything else to the vehicle that will impact efficiency. The car simply displays the calculations as a result of whatever mechanical change has occurred.

@@sshah2545 So where is the car getting the information about distance traveled? I'm guessing from the wheels. If so, I think different diff won't affect the calculation as long as he's using same size tyres.

@Seb incorrect again lol. The car is getting information about distance traveled from the engine. That's why when you change the stock wheel size your speedometer is permanently incorrect. Your car is calibrated at the factory. So, say a Subaru BRZ Limited with 18 inch wheels, the car is programmed to calculate that X rotations of the of engine, results in Y rotations of wheels, = Z speed. If you change the wheel size, the car is still using the same X variable, to calculate Z. Which is why if you put winters on, on different sized wheels, you literally need to know the offset % so you can know that when the speedo is reading 50mph, your car is actually driving 57... as an example. You're right overall btw. To understand fuel economy, go off the what the gas pump says. But the dude in the video makes valid points. There were reasons why the car might be more accurate, with it's optimistic economy estimate, based on things like sitting behind trucks. But to be clear, the car doesn't, and will never take final drive ratio into account. It is calibrated at the factory. Unless you recalibrate, once you change something, things like the speedo will always be wrong. Fuel economy however is different. But why it's different is what matters.

Because for some reason the gas pump is wrong when putting gas in the car sometimes. The amount that goes in isn't always the same. It could be warmer or cooler when refueling. I tested this recently with a toyota sienna. The gas gueage was all wonkey ambit the amount of Miles I got would indicate a 43mpg average did it by hand and got 37mpg. I did it again and again u got 43mpg but this time tmby hand the avg mpg was 43mpg lol. Did it again and go4 42.8mpg and by hand it was 42mpg. I think it was a fluke the 1st time with the vapors or something even though I filled until I can see the gas

Bro how the hell do people still think ac effects mpg.

Increase fuel burn, to be clear.

They're not my taste, but 90% of wheels look the same anyway. If he likes them that's all that matters.

Enkei is the sweet spot in price and quality.

Not the wheels. Enkei rpf1 looks great on most cars. It’s the fact that he went with a really meaty tire setup.