b2884987

Does anyone know what is the "sweet spot" speed to obtain maximum MPG? I've been trying 45 MPH on cruise control and 55 MPH on cruise control, but the info dash both say around 30 MPG for both of these speeds. Though however, I get a slightly higher MPG number with a speed of 55 MPH. According to the EPA, the best speed for most cars is 50 MPH. However, we all know that different cars have different "sweet spot" speed. Have anyone been testing out the speeds to see which speed gets better MPG? It's so hard for me to test the speed out due to different factors, especially the slight grade incline.

Source: https://www.fueleconomy.gov/feg/driveHabits.jsp

maxSteel

I've never seen anything higher than about 23 mpg.

Lexmus

The best MPG is at the lowest speed where the car will stay in the top gear, for the RX300 that is 4th gear. My FWD RX300 typically will go into 4th gear at around 48 mph, so I should get my best MPG around that speed. Check your RPMs and determine that speed for your RX, and then measure the MPG at that speed while in 4th.

sktn77a

iTrader: (2)

Weve had our 1999 from new. The gas mileage has gone down a couple of mpg over the 17 years we've owned it. I now get 20mpg pretty much regardless of the speed I go. Maybe 22mpg at 65 on the freeway, 20mpg at 75mph, and maybe 18 around town but it's not a dramatic difference.

dicer

The real sweet spot maybe much higher speed than you would think. And there are good reasons for it. One brand car I drove got best mileage at 70 mph, the reasons can be because some cars start getting lighter from speed and pumping losses go down with more throttle opening. Some cars have a very low coefficient of drag so the old drive it slow theory doesn't apply.

hypervish

Last year on my road trip back from Chicago, I got 25.8 mpg and 26.0 mpg on two tanks. I was driving at 55-60 mph following another relative. It was painfully slow, but the MPG was fantastic!

The key is maintaining steady throttle pressure, and if that means losing or gaining a few MPH on hills, etc. then so be it.