MPG at high speed (07 Camry hybrid: 32 mpg at 90 – 100 mph)
 

I know we don’t have the autobahn in the US, but there are people who live in some central rural areas where high speed cruising is a way of life. Some parts of I-10 in Texas is 80 mph which is considerable more than the 65 mph highway speed most highway mpg is figured at. We made a trip into low population area of New Mexico recently and although the posted speed limit was 65 and we were doing 75, we were the slowest people on the road, so I decided to drive behind some speedsters and found they were going between 90 and 100 mph!

Here comes the other part, my elderly mother had to give up driving and we inherited a 2007 Camary Hybrid , which until this day, the only thing I liked about this car, was the fact it was free. Its heavy, 65 to 70 mph mpg is only about 35 – 36 mpg, steering has no feel, it doesn’t turn on or off well, and has a little trunk. But to my surprise at 90 to 100 mph for 3 hours, it averaged 32 mpg! The no feel steering and heaviness even went away at that speed.

Is 32 mpg at 90 – 100 mph as exceptional fuel efficiency as it seems to me? Are there any other cars that can do this? Why does the Camary Hybrid manage this? I did a little research and found it has a continuously variable transmission (CVT) and although a CVT allows a engine to run at the optimum rpm for fuel efficiency or power for any speed, it not quite as efficient as manual transmission or automatic with overdrive lockout for producing optimal mpg at a certain speed. But speed higher than highway mpg cars are tuned for, maybe it’s good thing? A manual or overdrive automatic engine rpm is going to be higher at 90 to 100 mph than it was tuned for maximum 65 mph mpg. The fact that this car is fairly aerodynamic 0.27 is probably another factor, but I was shocked that I could increase speed by 30 mph and only lose 3 to 4 mpg!

numbers may be suspect, how were they recorded?

I'm assuming you were drafting the car ahead of you.....yes ?

mpg numbers from Camary Hybrid computer. mph numbers from speedometer and GPS. No drafting, followed behind far enough police radar would have picked up them by themselves.

It's not 90-100 mph. but I'm getting low 60's mpg on 80mph interstate trips, 80mph being as fast as I wanted to go on a continuous basis on a 70mph PSL interstate. I've done some short 90-95mph runs to test the upper limits of lean burn in my car (I didn't reach the max lean burn speed), but since my max lean burn throttle setting of 6.0usec at 65mph gives me about 50mpg, the 4.5usec throttle it took to maintain 93mph should be getting better than 50mpg.

drove a chevy malibu this weekend and recorded 34mpgs average @ 78 w. intermittent ac use in hills. so i guess your numbers are entirely plausible.

Its very impressive that you can get such good mileage at that speed...

I have to be that one guy who points out that 100MPH is very dangerous, bordering on reckless, no matter what everyone else is doing. Speed is the single most significant variable in accident likelyhood and severity of impact force should one occur. Speeding is indicated as a primary factor in more fatal crashes than drinking or cellphones, and has an exponentially larger effect on impact force than vehicle mass. At 100mph you don't just have twice the braking distance and twice the potential impact force, you have four times as much of each. At that speed crashes are often fatal even with seatbelts and airbags properly used and deployed. Consider that crash tests are only done at about 30mph.

I'm not one to judge. In my younger days I used to hit 100mph every single day on my Ninja EX250R during a stretch of my 50 mile commute.
Just keep in mind what your risking, and be safe out there.

We used to own a 1995 Dodge Neon, manual steering, no AC, base engine with automatic. I got 41 MPG in it ONCE on a road trip at 80 MPH moving with traffic in the fast lane. Temperature was 80 degrees. I don't remember wind direction, but am sure it was a tailwind.

Driving normal (steady 60 MPH), I expected 40 MPG on the highway. Got 46 MPG at that speed once under ideal conditions.

So, yes, good MPG at high speed is believable under ideal conditions. But a one year average MPG is more realistic.