37.5mpg

<div class='quotetop'>QUOTE(adam1991 @ Apr 4 2007, 07:13 PM) [snapback]417913[/snapback]</div>

Do you calculate the mileage by hand as well?

I find the MFD mileage to be somewhat inacurate: enough for it to be just an approximation of the real tank mileage.

I also believe the reason for your lower mileage is that you drive your Prius like any other car. That is OK of course as it is your choice to do so, but then you cannot imply that other folks' mileage is not realistic. There is one aspect about your Prius that already sets it appart from other traditional cars, and that is the instrumentation. After all, you paid for that instrumentation - why not use it? It is literally beging you to do so. And the best part about it is that you don't have to do anything illegal to get better mileage.

I believe I do daily real world driving, in a nasty-real world climate, and like many here I will definitely take my 2007 Prius to the upper 50's (if not higher) during the summer months. To give you an idea, 37mpg is what I get in -30F weather and 20 minute city commutes.

PS: Having proper tire pressures can help as much as 10mpg or more as well.

Cheers;

MSantos

 

<div class='quotetop'>QUOTE(adam1991 @ Apr 4 2007, 07:13 PM) [snapback]417913[/snapback]</div>

Well, short trips with the heat on in cold weather will result in about the kind of mileage you're getting. When you say short, how short? Also, are you doing lots of short trips together or does the engine have time to cool off between trips? What's the air pressure in your tyres? That can have a big impact on mileage.

I'd say the opposite. The MFD reading is reflects the amount of fuel that passes through the fuel injectors. Manual calculations are done by how much you put into the tank, not how much you actually burned. Given the fuel bladder's variable volume (as a function of temp) and variability in the testiness of different fuel pumps I'd say that the MFD readings are FAR more consistent.

 

Hi Adam,

I drive in the real world, and just finished a tank at 54.5 mpg by the MFD (about 450 miles to just under two pips). Fill up was 7.9 gallons, but with the colder weather the fuel bladder probably shrunk over the fill day. Was at 55.0 mpg till the cold front came through this morning, and had to drive home in a cross wind gusing to 30 mph at 30 deg F. I have been above 50 mpg on each tank since the mid February.

It would be helpful if you describe your drive, and your approximate location, and commute distance.

For highway driving I tend to stay around 65 mph when traffic is not limiting. I am limited to below 65 mph both my morning and evening commutes while on the interstate about 1/5 of the 20 mile distance. Sometimes 65 mph is the far left lane, sometimes its the center lane, and the left lane is down around 60.

I usually do not use the heater unless its below freezing, but there is heat coming through the vents anyway after 10 minutes. My commute is only 23 miles. The heater is mostly used for defrosting. Which has only been needed about 3 or 4 times in the past month.

There is lots of information on Prius chat about how to drive use the Hybrid Synergy Drive. Check out : http://priuschat.com/New-owner-Want-MPG-he...rst-t15311.html .

One thing about the Prius is the gas pedal. Its not directly tied to a throttle plate. So, there is no need to keep it pressed down at some level to keep the throttle plate open. Doing so in the Prius keeps it ready for quick throttle response, and mostly disables the economy routines of the program. Lifting your foot completely off the throttle for a second will also not decellerate the Prius like a traditional car. But, it does comunicate to the control program (apparently) that you want to reset the mode of operation. Try that and see what happens. Bring the gas pedal up slowly till the car is at the cruising speed.

The cruise control also helps mileage a bunch on flat road highway driving.

 

Two miles - no wonder!

No chance for the engine to warm up.

 

<div class='quotetop'>QUOTE(tripp @ Apr 4 2007, 08:46 PM) [snapback]417961[/snapback]</div>

Sorry tripp. I don't quite follow...
If you did not burn the fuel that you put in the tank then where did the gas you pumped in go?

I am pretty familiar with the bladder's "varying" capacity issue. But in my case, I purposely never fill-up completely; so the bladder is not a problem for me at all.
My personal observations and experience is that the MFD seems to frequently over-estimate the trip tank mileage. Because of this, I believe my tank/mileage calculations are the authoritative measure of my car's FE performance.

Cheers;

MSantos

 

<div class='quotetop'>QUOTE(adam1991 @ Apr 4 2007, 10:21 PM) [snapback]417975[/snapback]</div>

Consider pumping up your tires to 44 front, 42 rear. They're not going to wear out more quickly that way, trust me - search the board for proof. 35 psi is still pretty squishy. Your short trips are killing your MPG, but maxing out the tires helps.

 

<div class='quotetop'>QUOTE(adam1991 @ Apr 5 2007, 12:16 PM) [snapback]418225[/snapback]</div>

I've NEVER been in the 30's.
We had a 2005 for 2+ years, now have 2- 2007s. Our trips are usually 10+ miles but there are the short local trips in the mix as well.
The 2007s appear to be attaining slightly better milage than the 2005, 47mpg or so. "not "broken in" as yet (under 1k miles each).
Our tire pressure is 36 psi or thereabouts.
We are not "AR" about mileage, just use MFD numbers.
Would think mileage in the 30's means some malfunction unless there are special circumstances in "the world baby, the world"
Carl

 

<div class='quotetop'>QUOTE(adam1991 @ Apr 4 2007, 11:21 PM) [snapback]417975[/snapback]</div>

With a driving pattern like that, 40 MPG is about the best you will get in the summer time. When temps are consistently below 32, you will get around 30 MPG.

My wife and I each have a Prius. In my Prius, I typically drive a 15 mile each way commute, averaging about 40 MPH for most of it. In the summer time, I'll get as much as 52 MPG. In the coldest part of winter, I may get as low as 40 MPG.

My wife drives almost exclusively short trips of less than 5 minutes in length. In the summer time, she might get a little over 40 MPG. In the coldest part of winter, she'll typical get around 30 MPG. She's gotten as low as 28 MPG.

The Prius engine runs less efficiently while it's warming up. That's usually about the first 5 minutes in the summer and maybe as long as 10 minutes in the winter. You can see it in the Consumption Screen graph. Drive you Prius for 20 minutes, and watch the 5 minute bars that are plotted on the graph. The first one will be around 25 - 35 MPG. The subsequent ones will typically be near or above 50 MPG. If your trips are short and the car is operating mostly during the engine warmup phase, you won't get great gas mileage (for a Prius anyhow).

<div class='quotetop'>QUOTE(malibucarl @ Apr 5 2007, 12:51 PM) [snapback]418253[/snapback]</div>

Carl, watch your Consumption Screen graph. You will likely see that the first 5 minute bar is between 25 and 35 MPG, depending on the season. Now, imagine if you always stopped the car and let it cool down as soon as the first 5 minute bar appeared. What do you think your gas milage would be if you did that?

 

We live in Arizona and use the AC about two-thirds of the year. My wife commutes in our 2006 Prius 35 miles each way every day, over half on a freeway at around 70 mph. I drive it occasionally, mostly on Interstate 10 betwen Phoenix and Tucson, where I cruise at 70 to 75 mph. I hardly think our driving would give optimal fuel consumption, but the worst tank we have seen has been around 46 mpg and we routinely see 48 to 49.

We did see a drop when we carried four large people and their bags on a cold weekend, but it hardly made a blip in our overall consumption.

Report back when you've run a few tanks through it and after the weather warms up.

Mike

 

In over 2½ years driving a 2004 Prius, traded last Nov for a 2007 Prius, manually-calculating every tank of fuel, I have found the MFD to be more than 98% accurate compared to the manually-calculated figures. The manually-calculated figures even out over multiple tanks, but can vary quite a bit from tank to tank.

For me, that's "close enough for 'Government Work!"

 

<div class='quotetop'>QUOTE(Marlin @ Apr 5 2007, 01:34 PM) [snapback]418283[/snapback]</div>

Actually I meant between fillups. As mentioned we aren't too AR about the mileage just check it most times when adding gas.
Carl

 

What's your tire pressure?

Try 42/40. It's not going to hurt your tires, you won't feel that much of a difference in the ride, but your mileage will increase.

 

<div class='quotetop'>QUOTE(malibucarl @ Apr 5 2007, 04:38 PM) [snapback]418406[/snapback]</div>

You missed what I was saying. All I was saying is that for the first 5 minutes or so after startup, most people get between 25 and 35 MPG depending on the season. If the car is driven only for 5 minutes or less at a time, then it's not going to get above 40 MPG. The reason why some people get incredible gas milage and some people get crappy gas milage has a lot to do with how long their trips are.

If a large percentage of your driving occurs during the first 5 minutes or so while the engine is warming up, then you will get closer to 35 MPG in the summer, and less in the winter. If a large percentage of your driving occurs when the engine is already warmed up, then you will get closer to 50 MPG in the summer.

 

Considering all of the things you mentioned in this thread, your mileage is pretty much exactly where I would expect it to be. The combination of short trips and lower tire pressure will kill the mileage. Many people on this board have pushed the pressure up to 42/40 with no problems, but it does make the ride "harsher." Throw in AC and heating, and I'm not at all surprised. Things may get a little better after the car and the tires are "broken in," but I wouldn't expect dramatic improvements with your combination of driving habits and tire pressure.

 

Well Adam1991-

since you live in the "world," it's tough for all of us to offer you targeted advice.

the first thing to check is your tire pressure- it is the biggest culprit in lousy gas mileage.

I know my short commute of 10 minutes or less does not allow the spaceship to "warm up" and my mileage drops. I try to get a good drive in every tank ....

If I need the heat, I try to wait after the first 5 minutes if PRACTICAL, obviously, sometimes it's not if visibility is a factor.