[JoLaine2]

Hello all - I've had my 2004 for about 10 weeks now. I'm concerned about mileage, and from the sounds of others, its a topic that has many of us disappointed. But I think my situation may be different. I get 42 in town, very consistently. I'm in Savannah so it's rarely cold. I get 47 on the road, very consistently. In town, the gasoline engine runs when I think it shouldn't. It often runs when I'm stopped. The gasoline engine ALWAYS kicks in by the time I accelerate (gently) to 10mph. I can be crawling through a parking lot at 10 mph with the gasoline engine running. I drive very conservatively. My dealer says there is nothing wrong with the car. Is anyone else experiencing this?

 

[efusco]

Nothing you've said suggests a problem, in and of itself. It is normal for the ICE to kick in from any stop. Depending on how far you're going in a parking lot and the SOC of the battery the ICE may kick in to recharge. Your mileage is a little lower than I'd expect based on the average high and low temps for Savannah, but not significantly so and there are many variables that you haven't elaborated on that come into play.

I guess the first few factors that you can control that may have an impact on both the MPG and frequency/duration of ICE operation are:

1)Oil level--go out and check it now. If it is even a tiny bit above the 'full' mark go to the dealer and have it drained to just below that level.

2)Tire pressure--the pressures listed in the owner's manual are much lower than what most folks feel will provide optimal fuel efficiency and tire wear and handling. I use 42f/40r, others us up to 44f/42r and notice a significant improvement.

3)Temperture control (A/C)--turn it down or off completely when ambient tempertures allow (which looks like almost always in your area). This is a very significant drain on MPG. I found an approximately 4mpg gain from one tank to the next with almost identical ambient tempertures by leaving the A/C completely off or using only on the lower settings (65 or 67 degrees) in the coldest temps (down to 18 degrees). I wore a warm coat and felt quite comfortable. Until today I hadn't seen a temperture greater than 48 degrees on this tank of gas with averages probably closer to 32-34 degrees and I'm currently showing 48.3mpg on the computer with about 3 bars left on the fuel guage. I drive at about 1000 feet elevation with lots of hills, mix of short (10 minute/5mile) commutes and longer commutes (15 miles/25 minutes).

Finally:
If you have a PDA you can check to make sure your car is operating within specs and learn a lot about the physical variable that affect your MPG and how much they affects your MPG by using Wayne Brown's THS II simulator:

http://www.seawell.net/Prius/PalmTHS2/THS2HiRes22.zip

I'm currently working on a long article about where the MPG ratings come from, what affects the mpg, and how you can improve your mpg. Maybe have it out next week.

 

[mrv]

how long (time/distance) is your
"city" driving?

the first 5-10min you'll still be
in warmup, so the engine may run
more often.

have the AC or defrost on?

 

[RSnyder]

Don't make the mistake of thinking that one of your driving goals is to maximize the use of battery power. Rather than dragging out your acceleration trying to keep the engine from starting, accelerate briskly but not full out (2/3 to 3/4 down on the accelerator pedal). When you reach your desired speed, then quickly back off the pedal slightly more than necessary to maintain speed and then feather it forward to maintain your speed. This will allow the Prius to run long distances at moderate speed mostly on battery power. It's not wasteful to run the engine during acceleration when it's under enough load to be efficient. It's during moderate speed cruising that engine is lightly loaded and thus fairly inefficient. The Prius is already programmed to recognize this. Don't try to force it to run battery only except when you know for sure that the upcoming terrain justifies it (i.e. you're going to start a long decent soon and need room in the battery to store more energy).

Things to remember:
- The battery is small, don't expect it to be your primary source of power.

- The engine is least efficient under very light or no load. That's when you want it off.

- The battery allows use of a smaller, slower responding, lower emission engine. This is it's main contribution to increased mileage.

- The battery allows capture of braking energy (regeneration). That's it's next big contribution to increased mileage.

- Normally, there is a net loss of energy if the engine is used to charge the battery which is later used to power the Prius. This can turn into a gain if at the time of charging the engine is running under a fairly heavy load and at the time of battery use the engine would otherwise be running under a very light load.

- Flooring it runs the engine full out and discharges the battery. This is also inefficient. Try not to go more than 3/4 accelerator pedal except where traffic conditions insist otherwise. A non-dented Prius is more aerodynamic

 

[Guest]

Hi Efusco:

___Have you had an opportunity to look over the Fuel Efficiency Techniques FAQ over at InsightCentral.net yet? It might give you a head start on your own Prius fuel efficiency tips and tricks. In my short experience with the Honda Insight as well as reading up on tips and tricks from the real high mileage pros in the Honda-Hybrid forums on Yahoo and those in the Insightcentral.net forums, there isnt a better group to learn from imho.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:1yr33fyd][email protected][/email:1yr33fyd]

 

[Joel]

Just to reinforce the tire pressure suggestion - when I went to the dealer for my 5000 mile service, they lowered tire pressure to 32psi all around - this had a noticeable 8MPG effect on fuel economy over the 40psi I usually run.

 

[efusco]

Thanks Wayne, I'll pirate that site freely.
--evan

Hi Efusco:

___Have you had an opportunity to look over the Fuel Efficiency Techniques FAQ over at InsightCentral.net yet? It might give you a head start on your own Prius fuel efficiency tips and tricks. In my short experience with the Honda Insight as well as reading up on tips and tricks from the real high mileage pros in the Honda-Hybrid forums on Yahoo and those in the Insightcentral.net forums, there isnt a better group to learn from imho.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:3oztfdfs][email protected][/email:3oztfdfs]

 

[JoLaine2]

thanks and further info on tire pressure

Thanks everyone - You've been much more helpful than anyone at my Toyota dealer or the Toyota 800 #! I'm going to recommend they check out this site to keep up to date. My only question is about the tire inflation. I've heard Tom and Ray Magliazzi caution against running higher tire pressure due to safety issues. Would the 40-42 pressure recommended on this list be a safety issue?

 

[moocatdog]

Re: thanks and further info on tire pressure

Thanks everyone - You've been much more helpful than anyone at my Toyota dealer or the Toyota 800 #! I'm going to recommend they check out this site to keep up to date. My only question is about the tire inflation. I've heard Tom and Ray Magliazzi caution against running higher tire pressure due to safety issues. Would the 40-42 pressure recommended on this list be a safety issue?

JoLaine2,
I've found that most Toyota personnel are clueless about the Prius. With a little digging you can probably find someone at a dealership in your area who's excited about the Prius and its technology. If you do, bake them a cake and make sure they're the one who works on your car.

As for your tire inflation question, there's been a lot of discussion here on that topic and you would do well to snoop around a bit more. Here's a link to an older string that I found interesting:

http://www.priusonline.com/viewtopic.php?t=779

If that link doesn't work, go back to late December of '03 in the "General" category and you'll find it.

Also, I would love to hear what Tom and Ray have to say about the Prius and they'd surely have great fun with your name! Why not give them a call this weekend and then report back here?
Drive happy,
Moo

 

[mrv]

Re: thanks and further info on tire pressure

Thanks everyone - You've been much more helpful than anyone at my Toyota dealer or the Toyota 800 #! I'm going to recommend they check out this site to keep up to date. My only question is about the tire inflation. I've heard Tom and Ray Magliazzi caution against running higher tire pressure due to safety issues. Would the 40-42 pressure recommended on this list be a safety issue?

All Prius have the Toyota recommended pressure of 35psi front, 33psi rear.

The OEM Bridgestone Potenza RE92 XL tires (in the US) for the 2001-2003 Prius has on the sidewall the marking of max cold pressure of 50psi.
The OEM Goodyear Integrity (in the US) tires on the 2004 Prius come with a max cold pressure of 44psi marked on the sidewall.

So long as you're not running UNDERINFLATED (less than Toyota's specs) or OVERINFLATED (over the max pressure listed on the tire), you should be OK.