PriusChat Forums - Gen III 2010 Prius Fuel Economy

Insight gets better MPG than Prius???

bighouse — Sun, 15 Nov 2009 01:22:06 GMT

At lunchtime today I pulled into a Taco Bell drive through but just before I did I saw a white Prius in the lot and thought I'd go ahead and pull in next to it to eat (yeah- don't hassle me about eating in my Prius- I'm a neat enough eater!). So, after getting my food at the drive-thru I pull in next to the aforementioned car...which, as it turns out, was a brand new white Honda Insight. First one I've seen...it's VERY Prius like from the outside. So, I eat and await the return of the owner...

She returns and, after buckling her little girl into the baby seat in the back, allows me to look into the cabin. She tells me she looked at both, but couldn't read the dashboard on the Prius. She liked the ride better in the Prius, but thought her car was a better value for a couple of thousand dollars less. Then she also told me she gets an average of 60 MPG on her regular driving...was she pulling my leg? I mean I know that the Prius can get very high MPG ratings at different times based on what some Hypermilers have documented, but really- 60 MPG as an average for a Honda Insight? I thought their MPG was lower than a Prius?

Can I Do Better

Adium — Fri, 13 Nov 2009 21:09:05 GMT

Hi everyone.

I take my prius to school every morning and back every evening (weekdays, anyway), and I can't seem to do much better than 40 mpg.

School is only about 5-8 minutes away, and it's no more than a 5 mile trip. There are a lot of stops on the way--four stop signs and three traffic lights. The trip is relatively flat, though in the mornings I do go down a pretty big hill and in the evenings I go up it.

When I accelerate is usually does go into PWR on the HSI. I try to drive as naturally as possible, with the exception that I start coasting earlier than what feels normal into a stop sign/light.

I have some idea, but can someone tell me exactly what's happening when the engine is warming up? It's warming up for most of my trip and I'd like to know if there's anything I can do to help that. (I can't get an EBH and I can't park in a garage.)

Also, I've read it's bad to purposefully use only battery (the left side on the HSI display). Is this because the battery must later be charged with gas? Would it be good to try to use only battery in the last, say, 2 minutes of my trip since the engine will have to warm up the next time I start it anyway?

Thanks!

Interesting stats from Honda

Engelz — Fri, 13 Nov 2009 19:37:57 GMT

Honda's 2009 NAVTEQ Navigation Benefits Study shows non-hybrid drivers relying on navigation systems use 12% less fuel and reduce carbon dioxide emissions by 21%.

I guess you would slash these percentages in half to three-quarters as it applies to a Prius?

Getting Better Mileage

john burns — Thu, 12 Nov 2009 18:27:40 GMT

Well I'm getting better at driving my new Prius

Have about 1500 miles on it, and got 59.8 on my last tank.

I am striving for 60 on a tank, but have not been successful yet

But I am very happy:)

Help for a Gen II driver

nooaah — Wed, 11 Nov 2009 21:23:08 GMT

I'm only about 700 miles into my Gen III. However, I still haven't figured out how to glide! I'm averaging 57mpg, which is 6 mpg better than my Gen II at the same age and 7 mpg better in similar weather conditions.

I've caught on quickly with the HSI, but I don't really know if I'm ever truly gliding. When looking at the power flow, there is always energy either coming from the battery or going into it. I can black out the HSI, but not the energy flow. Is there something I'm missing?

I'm a pulse and glide veteran with the Gen II. I was getting 56mpg with it before it was destroyed; so if I'm making a noob mistake, it's a Gen III-specific noob mistake that I haven't read about in these forums.

Thanks in advance!

Influence of speed, temperature, and weight on MPG

Indyking — Wed, 11 Nov 2009 17:27:36 GMT

OK folks, I tried to insert the data chart in the post as opposed to an attachment but had no success.

Anyway, the chart attached (open in a second window) is MPG data collected after ten 365-mile-long trips. Some important info about the trips and chart:

-These are one-way trips in the Midwest, fairly flat, under different conditions inbound versus outbound; therefore, it did not make any sense to combine them in 5 round trips.
-The gasoline used was always 87 octane (Shell or Speedway).
-This is just a preliminary data; I plan to do a more complete analysis after collecting 100 trips in one year! (Yes I drive a lot!).
-TEMP was the temperature observed by the Prius thermometer during the majority of the drive. In cases where there was a significant change in the temperature from departure to arriving, I just used a calculated mean temp.
- MPH was calculated my Garmin (more precise than the Prius MPH gauge). Average speed varied from 55 to 67.7 MPH, but most often above 65 MPH. I got unprecedented traffic in my first trip which caused the MPH of 55. I usually cruise at 70 � 80 MPH using cruise control.
- The letters L, M, and H by the MPG line means light, moderate, and heavy weight, estimated to be <300 (L), 300-500 (M), and >500 (H) pounds including my weight.
Numbers in the x (horizontal) axis refers to 10 different trips, hereinafter labeled as T1, T2, etc, for simplification.
- The texts above the X axis (above the trip numbers) indicate when the heater was used and when there was significant rain and respective time percentages. 70F 100% means the heater was on all the time set at 70F. L Rain 60% means light rain during 60% of the trip.

Conclusions:

The obvious: FE in the Prius is really similar to a category 5 hurricane, like someone pointed out elsewhere in this chat. Everything must be perfect for maximum performance. The combination of higher average speeds (MPH), higher weight, and lower temperatures cause a very significant drop.

Surprise: The data from Trips 2-4 (T2-T4) suggested that temperature itself caused a MPG drop regardless of the speed and this can be aggravated by weight. I thought this was a surprise because these are essentially 99.9% HWY-only trips, therefore, engine warm-up has little impact. Just the cold air by itself results in a hit.

TEMP, TEMP, TEMP...: T4-T5 reinforces my point above, i.e. just the increase in temp itself was sufficient to improve the MPG despite of the increased weight and higher speed (MPH). Look at T8-T9 now. Despite of the lower speed (same weight), there was a drop on the MPG caused by lower temperatures, so folks I'm convinced that temperature is the major factor considering the speed range I drove so far. Note that, during colder air temperatures (T2, T3, T4, T8, and T9), the heater was often turned on for at least 50% of the time. I believe, the heater may have contributed to the MPG drops seen at those trips as it drags heat (energy) from the engine. T3 was poisoned for low MPG: Lowest temp recorded, heavy cargo weight, heater on and rain...

Unknown: Look at T5-T6. What does explain the steady MPG between the two trips in the presence of higher speed and lower temp? It should have a pretty significant drop on my T6 MPG but it didn�t. I doubt the lighter weight compensated the higher speed and lower temp, so, I looked at my records for those 2 trips and the only thing I changed was driving in NORMAL mode instead of ECO. Right between T5 and T6 I changed from ECO to NORMAL and I'm still keeping it in normal. Could that be a factor? I doubt it too� so not sure how to explain it� maybe wind and humidity? I did not record those 2 parameters�

Attached Thumbnails

Odd fuel gauge behavior

lamontcranston — Mon, 09 Nov 2009 14:32:29 GMT

Here's the skinny:

-Driving home with about 140 miles since fill-up. MFD says about 63mpg, so assuming the normal error, I've used a little over 2 gallons.

-Fuel gauge shows full minus one pip. I would have expected full minus two at this point.

-Then, after a run that was neither strongly uphill nor strongly downhill, the fuel gauge goes up to completely full for about ten minutes.

-Then, it goes down to full minus one for about ten minutes, then full minus two.

-When I got in it this morning it showed full minus three, then after about ten minutes went to full minus two. I drove another 50 miles and it is still at full minus two.

-Distance-to-empty seems to stay consistent through this period.

So, does anyone have an idea? This may be my first tank on "winter blend"... is there a possibility of foaming or something? I don't know if the Prius gas gauge is fed by a float like older car tanks, or is measured by weight, or what.

Should I be worried if this behavior continues? Has anyone else seen this?

Does EPA test with Ethanol Gas for MPG

alfon — Sun, 08 Nov 2009 17:37:15 GMT

I posted a similar thread sometime ago when the EPA conducts their test for MPG on new vehicles does the gasoline they use for that
testing contain 10% Ethanol as quite a few states mandate for
all year long use in their gasoline. I don't believe anyone really knows outside of the EPA and they are not telling.

If they do use the 10% Ethanol blend you will see a 10% drop in MPG believe me.

If the car compaines are conducting their own testing you can bet they will use regular gasoline with "NO" ethanol to get the best obtainable results.

If your state does not use Ethanol in gasoline don't ever let them.

alfon

Gen III Mileage Estimate in Power Mode

66corvette — Sun, 08 Nov 2009 16:31:50 GMT

Just took delivery of new silver Prius IV this week. Wow - what a car! My wife does not like the pokey behavior in eco mode and likes to drive in power mode most of the time. What gas mileage can we expect to obtain if driving mostly in power mode. Also -would driving in power mode adversely impact on the break-in period of the engine.

Thanks for your input

E10 VS Straight gas

ALS — Sat, 07 Nov 2009 02:32:36 GMT

I can't believe the difference between the E10 and Straight gas.
My last tank was E10 I bought at Sunoco. I couldn't get better than 46 mpg measured in the car.

This tank with straight gas that I bought at a Gulf with a little over 100 miles on it so far is getting 56 plus mpg (HSI). The tank before this last one of E10 was also straight gas. I got a tank average of 52 mpg measured. HSI said 53 mpg.

The only reason I bought the Sunoco E10 last month is because I had .40 off per gallon on my fuel perks card. These cents of per gallon I can only redeem at a Sunoco gas station.

With out major money off per gallon, the E10 is a really bad deal if your looking for top fuel mileage.

Even with my Volvo 960 which is my long distance highway car there is around a 10% difference between E10 and straight gas. 26.5 mpg E10 vs 29.25-29.75 mpg with straight gas. :eek:

The AC effect

rwdorn — Thu, 05 Nov 2009 23:26:28 GMT

What is the estimated effect of running the AC while driving? I realize there are many variables that can effect this figure but maybe someone has observed xx mpg drop w/AC verse w/o AC.

Thanks....

First Road Trip Results!

Black Swan — Thu, 05 Nov 2009 15:16:37 GMT

I just got back from my first road trip to Atlanta, including interstate driving from 60 - 75, varying, and city driving as well as four-laned road driving 45 - 50 with towns and stoplights. I am so pleased at how well the car handles. Such a joy to drive. I didn't find a noise issue. It seemed quiet to me. The mpg was simply amazing -- 66.3 miles per gallon. How I love this car!

Newport Beach, Newport Coast MPG Real World

priusblogg — Wed, 04 Nov 2009 20:53:34 GMT

Newport Beach is ALL stop light to stop light. If you can get through two consecutively call it a great week, so every intersection you get it in the rear end by the City developers: There are lots of hills, many like Newport Coast drive, steep and start from a near standstill.

First Fillup:
416 Miles on OD
Power Mode On 100% of the time.
Wheel Covers Off.
Cons said 45.6mpg
Got more accurately about 42+mpg, which I think under the above circumstances, is very damned good!
Took exactly 10 gallons to fillup. No idea if dealer did this, doubt it.
$2.99 = $30.00
Tires were all 10lbs low! I never checked when taking it from dealer, checked at fill-up and corrected.
A/C on 80% of time. I drive with A/C like a crazy person...
Driving mostly normally, occasionally peetering along in neighborhoods on 100mpg mode, but plenty of hard runs off stop lights.

When I got this car, I figured with my lead foot, if I got 38 I would be happy. I am very impressed.

Does CA have a winter blend gas starting November?

hschen — Wed, 04 Nov 2009 20:40:32 GMT

I just refilled at Costco, Tustin, CA on November 2 and immediately saw mpg drops ever since (for 2 days). In my communting route, I can easily achieve over 60 mpg. But in the past 2 days, I have to try hard to maintain 55 mpg. I don't fill any less power. It has to be the gas. Does CA have winter blend gas starting in November every year? Or else.

DO GEN III SOLAR PANELS HELP MPGs?

doc3osh1 — Wed, 04 Nov 2009 03:43:07 GMT

I scanned through all the MPG threads and did not see this answered, so forgive (or redirect) me if it's been covered:

I'd like to see a somewhat complicated comparison:

Two 2010 Prius', one with the solar-panel package and one without, each driven for at least 1 full tank of gas (preferably for a few tankfulls) in three locales:

A. In Arizona/ Texas/ Nevada region: Sunny but hot enough to require Air Conditioning (which may reduce MPGs)
B. In Northeast (not that sunny but not hot either-- A.C not needed)
C. in Boulder or some similar place where it is extremely sunny but cold

Of course ideally the same drivers would drive the cars in all three places so the driving habits would stay the same, but in any event the point is to see if the Solar Panels are "worth it", and whether they are worth it for some people (some regions) but not others... I'd imagine Toyota might find this info somewhat useful, though I have no doubt their main reason for including the panels is for marketing cache.