You will not get 50 MPG if...

I live in LA. driving cautiously, I can easily get @ 50mpg. Driving like everyone else on the road (without going too nuts) I get about 48mpg.
Averaging about 9 gallons per re-fuel, thats about 18 miles a tank that I'm saving by driving very cautiously (aka slow). This means, every 2.7 fill ups I'm losing one gallon of otherwise saved fuel.
If gas is $3.00 a gallon, I stand to lose about $1.11 per fill up. Further, this means about $56 dollars a year (assuming 50 fill ups). Compare that to the amount a coffee drinking person spends on coffee per year (I dont drink coffee). All in all, that's not really a whole lot (at least for me it isn't) of savings versus how careful i have to be to save $1.11 per every 430+ miles I get out of my tank. There are practical ways to keep mpg up, but at the end of the day, there's a trade off in FE effort that will or wont make financial sense depending on your situation. For me, trying for 50+mpg is mostly for the fun of it, but I'm not the least bit bothered by 48mpg.

 

Welcome to the forum!
Shouldn't have to play with you buttons in a pinch... whenever you push over 80% into the pedal... all points converge into power mode anyway... so don't feel like you have less power in you get into trouble... it may not respond quite as fast, but its there.

 

Thanks! I took it out for another drive today - my average is now 53.5mpg. I understand there is some margin of error in that, so I'm probably not quite up to a "true" 50mpg, but getting quite close anyway.

I don't actually push the PWR button... i was trying to refer to the PWR zone of the HSI. HSI was the new acronym I learned today . I was actually quite shocked by the power the car has when you goose it. I had to pull out into traffic on a busy street, everyone's doing 50mph. This thing has some unexpected zip!

Still, my wife is on me about how slow I drive now. I told her my Formula 1 dreams ended when I traded in my Civic Si

 

There is a line you have to draw in the sand IMO.

As with anything... your car needs to serve you and not you serve the car.

Based on what "service" you need from your car will determine how you apply that.

Its like the speed limit... they say "if we drop from 55 to 50, we can save X amount of lives... but based on that premise, we could drop it to 5mph and save much more!.. Heck, we could just all walk and save much more!....... so everything has to be weighed to determine the best of two evils or the worst of two goods.

 

You're right - and obviously there isn't a linear relationship between speed and economy, or speed and safety. There's a relatively flat, sweet spot that serves all of those variables equally well.

I also seem to have some very different expectations for service from the Prius than I did from the Si.

I think the two cars are just the two extremes of that range of values that yields the best speed, economy, and safety. Just have to get her to see it that way too!

 

I pretty much don't hold back if I need to or want power, but I also don't put my foot into it any more than I really need. Right now I"m getting about 56mpg.... no recent freeway driving but lots of backwoods rural driving and in town.

 

as much as i "don't care" about the small gains i notice between conservative and normal driving, i do have a bit of envy for you all who find your normal driving gets you in the 56mpg region. LA is hills, and any flatland is a cause for the flow of traffic to stay around 70mph, unless, its 0pmh in traffic.

 

Your post is right on. There is a law of diminishing returns. If your last car got 25 mpg, you have cut you gas costs in half. To cut in half again you would have to get 100 mpg, and that would only save you half of the remaining half.

Thus making an effort to get 50 or more is for fun and bragging rights.

 

I drove a 98 a ford expedition for 10 years before i bought my prius. was seeing about 11 mpg. The truck was helpful at times, and a burden most of the rest. I'm now getting approx. 450% better milage than I used to.

 

true, true and its all relative. facts are, its simply EASY to get 50+ mpg in certain areas and being from the same general area is no guarantee you will do as well as your PC neighbor.

case in point. where i lived previously was next to water less than 200 yards from the very southern tip of Puget Sound which basically meant i lived on the side of a pretty steep hill sloping towards the water.

then i moved about 5 miles south. worked same place so last part of commute was the same, but the trip is nearly flat. averaging about 60 mpg on RT commutes.

well from the place near the water, my average commute was only about 54 mpg and the reason?? was that steep hill the last 6 blocks to my house. i would get about 62 mpg going to work in the morning which was steep downhill, very gradual uphill. then 50 mpg coming home.

so you see, one's 50 mpg could be a great figure or barely acceptable. just all depends on where they drive and what conditions.

 

I purchased my 2010 Prius about 2 months ago and I'm averaging only about 40mpg. I drive 5 miles to work (mostly uphill) but I've put 800 miles on the car and the mile is the same. Do I need to get it checked out?

Andrew, San Rafael CA

 

Other people, including me, have reported similar mileage with 17 inch wheels, when most of their driving is short trip stop and go. The smart guys tell us there is greater inertia and larger contact patch with the 17 inch wheels, decreasing mileage by 2 to 4 mpgs. I'm assuming the more you have to start from a standing stop, the worse your mileage is gonna be, especially with our larger wheels. Also, there is a 2 to 4 minute warm up period, so short trips kill the mileage.

 

I think i'm finally starting to get a hang of the P&G technique. I think my technique needs a little polishing as far as the ideal duration of the "pulse" and what the threshold for terminating the "glide" should be depending on the terrain... but I managed to pick up almost an extra 4 mpg over my typical average! When I pulled into the garage this afternoon, my average was 59.1mpg over ~60-70 miles.

My commute is about 50 miles round trip, mixed city and highway.

 

That is it in a nutshell. Because I regularly swap from stock 15" wheels (185/65/15) to 17" wheels (215/45/17) I see a 4-6mpg drop every time. It's just the nature of the mod.

 

As good as regen is.. it just goes to show you how much more it could be improved because theoretically if it takes allot of energy to get bigger wheels moving, it should be given back when you brake or coast for regen.... but unfortunately, there are lots of losses.

You would also think that once you get the mass moving, it should be altogether more harder to stop and so coast farthur, but again.... not.

I think the wider tires have more friction, as well has the fact they have to cut a wider path through the wind.

On a vehicle that has almost no friction on the wheels "like a train on steel tracks with steel wheels" this law of physics doesn't seem to affect so much.

 

My wife tends to get 45 - 50 mpg,
I average around 65, and expect 70+ mpg in nice (70ish F) weather

Two main differences I can easily identify:

• She anticipates poorly (much more brake use)
• She does not P&G

I think the excessive brake use is the biggest difference. Most of the car's miles are in suburban/smallish-city driving where aggressive driving is not demanded by other drivers.

 

I agree completely with you Alan. I would expect to be able to coast farther with my 17's due to being 6-7lbs heavier than stock but my stockers with Nokians coast alot easier.

 

. . . The speed limit where you drive is 70 and the prevailing traffic speed is c. 75, as where I drive, and you don't want to be a whole lot slower than that.

Probably the EPA might want to change its HWY test to include 70 mph driving, given that it's a legal speed in much of the country.

 

The US06 or 'Supplemental FTP Driving Schedule' 'High Speed' test is largely 65-80mph driving. It's been part of official EPA tests since the 2008 model year.

Fuel Economy Test Schedules

 

Commercial Trucks: The limits are 55mph in CA. There ARE a few companies that actually make their drivers adhere by it. Just today I saw one with a big notice on the back-end stating something like, "65mph ... this vehicle modified to go no faster". I wonder if post the notice so tailgaters won't shoot 'em when they fly by 'em.