Better MPG at 62MPH then at 55MPH

[serialk11r]

That's right, 8x the power for 2x the speed. That's why on the track, while a huge amount of energy is lost to braking, probably a bigger amount of energy is lost to pushing the car through the air at high speeds, which is why the brakes aren't being cooked with anywhere near the full output of the engine. It's why you need only 300-400hp in a "typical" sports car to hit 180mph, but to hit 250mph you need over 1000hp.

[mcrews]

Originally Posted by GRU

I have driven my car on the same road. At the same speed. At the same time ( reseting the trip mpg every 2 minutes ) and got different numbers every time because its almost impossible to have the same exact conditions even if they are only 2 minutes apart

Ok......

So the solution is to do nothing?

sure there are variables but the idea is to get a BASE idea of what the car does.

1. warm it up before first drive.
2. do it after noon (temp stay consistant for a couple of hours)
3. Up and down negates wind
4. don't do it on a windy day.
5. do it on a day over 70 degrees.

[broski499]

Wow! Talk about a response. Yes this is my Eco car, mainly because its just the car I have right now but it holds it own at 40mpg cruising

On that trip I talked about there is a lot of up and down and I coasted in neutral down some big hills which really boosted my mpg

I will do some A B A testing and let you guys know what I find and see if I can find the engine load gauge

Thanks for all the help guys!!

[ron]

ok all I am going to test the speed verses mpg quandry this weekend and will post the results. my last trip of 200+ miles one way yielded unexpected results. at 1950-2000 rpm mileage was mid 20s . I increased the speed to make my grandsons soccer game to 68-70mph and I had a mileage jump a big jump 6-8mpg at 2400rpm. I suspect the turbo sweet spot. I am going to try it again and will keep all informed

[MetroMPG]

You probably already know this, but measurements taken during a trip aren't the best way to do this.

You ideally want to: repeatedly drive the same segment of road one run after the other, in the same conditions, with a fully warmed up vehicle, changing only your speed on each run.

That's how to get the most credible figures/results. Minimize the number of variables that could be affecting your fuel consumption to just one: speed.

[gone-ot]

Drag is a second-order function of velocity.

...but,

Power is a third-order function of velocity.

[ron]

well I hope that I have found the point where all mechanicals are at their most efficient and I am using the fuel not wasting it at a lower speed. I am going to top the tank and drive by the scangauge for max mileage then when I exit the freeway I will top it off again and see the result, I already know that stop and go in L.A. is a fuel suck. Its worth a check .

[ron]

OK here it is we just got back from huntington beach .down to H.B. 304.4 miles 16.621 gal mixed driving 18.314 mpg running 67-68 mph. return trip home to S.L.O. ca 224.5 miles 10.149 gal all freeway 60 mph 22.12 mpg. see fuel log. bottom line is speed kills/stop and go is bad for mpg

[ksa8907]

Originally Posted by serialk11r

That's right, 8x the power for 2x the speed. That's why on the track, while a huge amount of energy is lost to braking, probably a bigger amount of energy is lost to pushing the car through the air at high speeds, which is why the brakes aren't being cooked with anywhere near the full output of the engine. It's why you need only 300-400hp in a "typical" sports car to hit 180mph, but to hit 250mph you need over 1000hp.

We don't notice air as having resistance really because we are accustomed to it, but it can be treated like any fluid. The faster you go the more you compress the air and the more it wants to act like a solid.