Premium gasoline

Putin!

Partly left, but mostly Trudeau.

Even then, 87 with Ethanol is better than 93 without ethanol. At least for our SUV's according to Adam.

C&D tested 4 cars with Prem vs. Reg fuel:
https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

Good news is 3 of the 4 cars showed no appreciable difference, the bad news is the one that did suffer from Reg fuel was the Ford Ecoboost.

no I am not trying to date you, But I love your replys. your never a D you just give out facts. you dont try and make others feel less.
I never thought the octane would change MPG and was surprised so many said it did. I guess it could be anything wind what ever anyways thanks for another great reply

oh damn has that ever happened? someone blew a motor and you tested the gas?
I always use 91 (Highest we have) but that would suck to chase after the gas station over a blown motor.

Well, based on a couple of disagreements I've been in on this forum, I'm not sure everyone would agree about the "never a D" thought. But sometimes even when you're just giving out facts you end up stepping on someone's beliefs which can lead to confrontation. But thanks for the vote of confidence!

Has it happened? lol lots of times. Who does it happen to? problem customers LOL. It's one of those things that will ONLY get looked for if the customer is a jackass for the most part.

The Prius needs only nine horsepower to maintain 60 mph. The article I read many decades ago said it takes 16 HP to maintain 60 mph and that was on a full-size sedan (a yacht in today's size classification). It stands to reason if the motor can produce enough horsepower at 10% vs.13%, it'll use less gas. As for cost-per-mile, that's different these days with a $0.60/gallon difference.

Really? I'd truly like to see some documented evidence of 9HP at 60 mph! As far as "it stands to reason if the engine can produce enough horsepower at 10% vs. 13% it'll use less gas". Not necessarily true. Do a google of BSFC maps and look at one. BSFC numbers when mapped against RPM and load are islands similar to compressor efficiency maps. Lower RPMs do not mean best BSFC numbers.

Best BSFC is generally at peak torque. However, we don't normally drive around at 60 or 75 at peak torque which means we're using some sort of throttling mechanism. Whether that's done by closing the throttle body, inducing an Atkinson-style mechanism through use of variable camshaft timing, or inducing EGR the BSFC maps are all over the place. The manufacturer purposely uses certain gear ratios to get the best BSFC numbers You're also not considering auxiliaries- pumps (oil, water), valve train (higher power required at lower RPMs) losses.

So, I'm not sure why you decided an article you read "decades ago" before any of these innovations is relevant. Let's take a Tesla. Very aerodynamic and more so than the Prius, wouldn't you agree? Their 75Kwh battery pack is rated at 255 miles (they don't list speed) so we'll just pick 4 hours equating to 63.75 mph (close to 65). At that pace, it's consuming 18.75 Kw. That equates to over 25 hp. The ST is nowhere near that aerodynamic and has an entire thing called an automatic transmission (which the Tesla does not) sucking up valuable resources. See where I'm going?

Our local gas chain must be seeing a tremendous dip in demand for 93. For several weeks, it’s only been 20 cents more.

Physics and drag coefficients haven't changed.

https://www.quora.com/What-is-the-power-required-to-keep-Prius-rolling-at-60MPH-on-level-road

You're right, physics hasn't changed- but you're missing the point. The 9HP calculated in that article is simply an approximation of overcoming wind-resistance...period. It does not take into account the HP to overcome other parasitic elements in the drivetrain: run the oil pump, water pump, transmission pump, alternator, etc. Not to mention frictional losses of bearings, tires, differential, etc. Those things are not inconsequential meaning it would require far more than 9 hp for the Prius to actually power itself down the road.