Disappointed

<div class='quotetop'>QUOTE(elcorazon @ Nov 5 2007, 07:28 AM) [snapback]534919[/snapback]</div>

Could be the usual things like your local terrain and temps but a lot could also be your driving style and the fact you have such shot trips. Nearly all cars get terrible gas milage on short trips because the engine is cold and running in a rich mode. So even a Chevy Aveo (rated at 28mpg avg.) will not get it's best mpg during the first 10minutes of a trip. You may consider getting an engine block heater AND doing a little bit of math to see how much money you are actually losing. I get frustrated at times because I cannot get 50mpg avg. in my car. Then I do the math between 45mpg-50mpg and 10k miles of driving and the amount is low enough that I don't feel so bad anymore.

 

<div class='quotetop'>QUOTE(elcorazon @ Nov 5 2007, 08:00 AM) [snapback]534941[/snapback]</div>

1. I'm kind of in the same boat here. I try hard and it doesn't seem to change too much.

2. Temps can play a huge part, especially on such short trips. Again, the engine block heater may be an option for you.

3. What did you air your tires up to and would you assume that your tires were low (below 30psi) on your prior tanks? What kind of tires? Have you had your alignment checked?

You definately cannot compare tank milage between two vehicles with different sized tanks. My Prius rarely accepts more than 7gallons of fuel and will go on average, 320-360miles to a tank. My truck used to do that as well but took 22gallons to do it. lol

Again, go do some math and let me know what you think. It's kind of eye opening. The others will give you some advice shortly and hopefully be more helpful than I was. Good luck.

 

well elcorazon welcome to the club!

Here's a link that might help you,
http://priuschat.com/New-owner-Want-MPG-he...rst-t15311.html

I've forgotten the name of Ed Fusco's post/thread which is a good one-post read.

Questions for you:

1. describe your average trip? If you are under 10 minutes consistently and have any hills at all in that 'under 10 minutes' you should be in the below 40 range. That's not a problem with the Prius or your driving per se just the nature of short trips on any gasoline engine.
2. What is your PSI exactly? I'm using 42 front and 40 rear, and that made a significant difference.
3. Describe your driving style? For instance it is a common misconception that to get the high MPG one must drive conservatively, please check out the thread, there are definitely non-intuitive techniques that can make even a 10 minute commute better fuel economy wise.

 

<div class='quotetop'>QUOTE(elcorazon @ Nov 5 2007, 11:42 AM) [snapback]534978[/snapback]</div>

not much more you can do then that, other than taking a longer route to avoid the lights.

Definitely, increase the air pressure. This seems to be the number one thing done on priuschat.com to increase MPG, so with that much evidence, I'd say that is job #1. Even in my worst case situation in SF it made a difference.

Here's a short list, someone will come along to point you to Ed's article. I never actually read the entire thread that I pointed you to sorry if it wasn't to the point enough.

1. increase tire pressure 42/40 front/rear
2. do accelerate up to speed, not racing, but smooth intentional acceleration, watch your consumption screen, but I've found 39 MPH the best 'sweet spot'
3. do anticipate stops, but not in an offensive way to other drivers
4. use heat and A/C conservatively, my mom used to call it "sweater (heat) and t-shirt (a/c)" temperatures
5. use the same gas station as much as possible, set pump to slowest rate possible
6. pulse and glide, accelerate a little past the speed you want to maintain, back off and apply as little pressure as possible to maintain speed and or desired MPG (there are more technical explanations all over the priuschat.com feel free to search, but that's my attempt at simplicity). I've found it works best at certain MPH flat and flat roads with the exception of 39 MPH and 59 MPH I'm often able to maintain those on slight grades, hmmm?
7. you are in prime country for a block heater, again search the threads.
8. you are probably a price candidate for an EV switch too, or do you have one? nonetheless if you can pick a route that has a downgrade in the first five minutes

OK, that's all my words I hope this is helpful?

 

<div class='quotetop'>QUOTE(elcorazon @ Nov 5 2007, 11:42 AM) [snapback]534978[/snapback]</div>

So u're saying that u're willing to go the extra mi to improve your mileage. Here's my 2 cents.

1. inflate ur tire to 44/42 psi (front/rear)
2. stuff your front grill (top and bottom). I'm in SD and I stuff my grill when the temp drops to 75F
3. get an EBH - engine block heater. Hey DANNY when is the next group buy on the EBH starting?

I don't think an EV button is for you. The key here is not to drain the battery because it can be costly in terms of FE. I would suggest that you accelerate (18-25mpg) up to speed and then feather to a little above 50mpg and maintain that mpg until you need to coast to a stop. above 40 mph you can feather to a little above 60mpg and maintain that mpg until you need to coast to a stop.

I'm avging 55mpg but my commute is about 30-40min RT. I am tempted to try and run an EBH off a battery at work to improve that #. My 1st 5minutes ranges from 25-35mpg. After that its usually 60mpg if i'm disciplined enough or the lights are in my favor.

 

Highway mileage will always be lower, as you are overcoming a lot of aerodynamic drag at those speeds. Your highway mileage is fairly typical, depending on speed, terrain, temperature, and weather.

Short trips will cause poor mileage, and colder temperatures will lower that even further. Be content that you are getting much better mileage than you would with a conventional car under similar circumstances. If you want to try to improve your mileage a bit, try some of the tricks and techniques suggested by the mileage experts here on PC.

Tom

 

<div class='quotetop'>QUOTE(elcorazon @ Nov 5 2007, 11:28 AM) [snapback]534919[/snapback]</div>

My bet is that your culprit is the temperature. I imagine that it has gotten cold enough for you to use the cabin heater. The cabin heater uses waste heat from the engine and in order to provide heat, the engine must be hot. So, you will find that the engine continues running at times it used to stop. For instance at that first traffic light you stop at.

Try this... Sometime early in you commute (maybe a minute or two in), when you stop at a traffic light or stop sign, see if the engine turns off. If it doesn't, then turn off the heater and see if the engine then immediatly turns off. I bet it will.

Since your trips are relatively short, this extra engine running during the warmup period has a big effect on your milage.

I have a 30 minute commute, and I usually see my milage drop from about 50 MPG during the early fall and late spring, to around 40 MPG during the coldest part of winter.

 

<div class='quotetop'>QUOTE(elcorazon @ Nov 5 2007, 07:28 AM) [snapback]534919[/snapback]</div>

Unfortunately, as is noted on this list, the gas gauge is notoriously inaccurate.
Do what I do - after filling up a full tank, and resetting one of the trip gauges on your odometer, I take the miles I've driven, divide that by exactly how much I put in, and then I take the computer's mileage into effect. I plug all that and oodles of other data into an Excel spreadsheet, and when you start seeing trends, you'll know which indicator is more correct. I'm finding that for the majority of the time, the MFD is about 1-2mpg more than what I'm really getting, but considering the varying terrain in Southern California, and that this still gets more than double what my old Camry got, I'm still more than satisfied.

Paul

 

<div class='quotetop'>QUOTE(elcorazon @ Nov 6 2007, 09:45 AM) [snapback]535466[/snapback]</div>

In colder climates some Prius owners cut a piece of pipe insulation (you can get lengths from any home improvement store) in half lengthwise. Then they squeeze the insulation between the slits in the grill. The keeps some of the cold air from flowing into the engine compartment and as such keeps the engine and catalytic convertor from cooling off as quickly. The Prius will run the engine to keep these components at operating temperature even if it doesn't need the engine for propulsion. By keeping them from cooling off as quickly you prevent wasting gasoline to heat them back up.

I got my engine block heater here at Prius Chat from a "group buy" a couple of months ago. I suspect there will be another one eventually. If you're in more of a hurry to acquire one, I'm sure others here will advise you on where to find one.

You live near Chicago. There is a PriusChat member, goes by the ID of FireEngineer, who lives in the Chicagoland area. If you ask nicely he'll probably meet up with you and install it for you. Also check out the Chicago Prius Group. They meet up occasionally at various locations in Chicagoland and at times they install the engine block heater at the meetings for those who attend.

I'm no expert on tires, but I believe the reason for the higher pressure in front is because of the weight of the car is not evenly distributed. It is a bit heavier in the front than the rear. By boosting the inflation in the front slightly, you even out the area of the tire that contacts the road across all 4 tires for most of your driving. Of course, if you typically carry 650 lbs. of cargo in the back for most of your driving, this may not hold true.

 

<div class='quotetop'>QUOTE(qbee42 @ Nov 6 2007, 09:16 AM) [snapback]535517[/snapback]</div>

Not necessarily. I generally gain 5mpg on the highway, although I admit the trip has to be +40 miles. Even using cruise control the mileage goes up.

 

<div class='quotetop'>QUOTE(elcorazon @ Nov 6 2007, 09:30 AM) [snapback]535564[/snapback]</div>

All other suggestions being good, I would add that a big part of your problem is that your trips are 5 minutes or under. If you are using any heat or defrost you will blead off all the heat the engine produces in that first 5 minutes. It is a common misconception with people (my wife) that the way to get warm fast in a car is to turn the heat on full and the fan on high right away. They don't understand that the heater is only carrying cooling water that must first be warmed by the normal working of the engine. Turning full heat on, just delays the warm up.

When you think about it, what other car can you get in, drive 5 minutes and have a warm car? None.

The idea behind the block heater is that you can start with warm coolant, and ergo start in a more effecient mode. The trade off is in the electrcity costs. Block your grill, use the heater and you will see some improvement.

Icarus

 

<div class='quotetop'>QUOTE(aaf709 @ Nov 6 2007, 01:42 PM) [snapback]535578[/snapback]</div>

Okay, I'll rephrase my statement: High speed driving will always produce lower mileage than moderate speed driving, all other factors being the same, due to increased aerodynamic drag. If I have to make all of my technical statements like this, my posts are going to read like a law review.

Tom

 

I'm in a similar situation as the OP in that my daily commute is 4 miles/10 minutes each way, and it's chock full of stop lights and stop signs. (Today I got lucky and only got stuck at one red light -- some days I get 'em all.) My mpg has averaged between 45-50 per tank since I got the car in April, and for my current tank I'm getting 43.8 so far (5 pips left). I can get at least 50 mpg during long highway trips but for my daily commute, I'm stuck in the mid-40s.

But, because I'm only driving a total of 40 miles per week to get to and from work, I'm using less than a gallon of gas per week to get to and from work. And I'm doing much better that I did with my old car (Camry) which used to burn through a half-tank of gas per week, and a bigger gas tank at that. So I may not ever see the really big gas mileage that some people get, but I'm still doing better than most people on the road. And the emissions are lower, to boot.