MPH to MPG Chart, Make your OWN

[spotaneagle]

ok so I Run 42 mpg at 68mph average and 39 at 73 mph (values I came up with two identical almost non stop-highway runs of 200 miles each)so I take 5 mph and divide it by 3mpg and that equals 1.67 mph= 1 mpg, worse case scenario 2mph=1mpg(due to my own overestimating)so take 60mph 8/1.67 = 4.7 mpg more at 60 mph so that means 46-47 mpg at 60 mph!!!, math does a body good (ok so 45 mpg to compensate for overestimating) whats wrong with this site is that everyone has a mpg but not a any certain speed the real debate in efficiency is at a set mph not a constantly variable mph value. thanxxxxxxxxxxxxxx
-angry hipi
ps that means
@ 53mph i would get 51mpg(49.5 to compensate for overestimating!)
happy computing

can you say i saved $20k+ on the hybrid thing?
read up on my car for mods including WAI

<3

[GasSavers_maximilian]

I'd love to see your mpg per mph for a wide range of speeds plotted out. I did this for my car a little while ago and it really changed my driving strategy.

[spotaneagle]

ok who gets what at 68 mph? perfect speed

[FrugalFloyd]

I don't have data at 68 mph, but I get 26 mpg at 72 mph, 32 mpg at 62 mph, and 38 mpg at 55 mph, all tested over 400 mile trips to my mom's house. Plotting that on a graph, I should get about 28 mpg at 68 mph.

[theholycow]

My car, with its short gears and decent torque, always does better with lower speed, in spite of its decent cD. I think if I got down to 35mph I'd get the best fuel economy.

I record my average speed in my gaslog, but that includes non-highway driving (60% of my commute) and probably includes idling at traffic lights (does anyone know if the ScanGauge II's average includes that?).

[GasSavers_maximilian]

Interpolating on my graph I'd get somewhere between 32-33 at 68 mph. 32 is my car's EPA highway estimate, interestingly.

[GasSavers_maximilian]

Originally Posted by theholycow

probably includes idling at traffic lights (does anyone know if the ScanGauge II's average includes that?).

I did a test while idling and I could see the average go down over time on the SG2. I had always read that very low speeds started to become inefficient as the very small loads coming from the engine got worse and worse efficiency. The idea was that 40-50 mph or so was a compromise between rolling and air resistance and the partial load problem. So much for that theory.

[theholycow]

Originally Posted by maximilian

I had always read that very low speeds started to become inefficient as the very small loads coming from the engine got worse and worse efficiency.

True, and the speed where the efficiency goes bad would vastly differ from one car to the next.

[GasSavers_maximilian]

I assume my car's lousy gearing ratio is helping to push it lower. Have to try other gears during my next test to explore low speed behaviour more. Not that I'm willing to drive any slower than I am right now.

[alvaro84]

If I had a ScanGauge or any other device to measure instant fuel consumption, I'd make an MPH->MPG chart (well, it would be km/h to l/100km, but it's just a simple conversion away...). I'm especially curious if the lower air drag and slightly lower rpms compensate the less favorable gearing ratio @50-60km/h (2500-3000rpm) in 4th gear compared to the 70-80km/h (2800-3200rpm) range in 5th. But I don't know how to get this info from my bike(s) (especially from Teresa, she has the brains and the same bus as the C1 caged scooter) I'd need a long, deserted road with decent quality pavement, constant weather and at least a few hours and a few litres of wasted fuel to test it without this kind of instrument