The great Prius mileage challenge. 818 mile tank!

Really?
Let me ask this then..........92% of my driving is side streets.....Is there a "total trip length" that is required to get a more efficient average then? I'm guessing what kills me is most of my driving is usually 12 miles or less.

 

There is no magic number with regard to trip length. But the longer the trip the better. Mine is 25 miles each way. During the summer my first 5 minutes is in a 25 mPH zone where I can do a lot of gliding. I normally see the first 5 minute bar at 50MPG. After that the rest are between 50 and 100+. I have very few stop lights on my trip. Those will kill your mileage also.

I live at the top of a hill and my workplace is across a valley on the top of another hill, about 150 in elevation lower than my house. While going down hill, my ICE normally does not run at all. I have one continuous section, 5 miles in length where I can glide (ICE not running) at 25 - 30 MPH. While going up hill, I target 35 MPH, meanwhile the battery is charging.

With careful driving, no air conditioning, two windows cracked open 3 inches, overinflated tires, 0W-20 synthetic oil, I can generally average 80 MPG. When I really put a lot of effort into it, I can get 85MPG on my daily commute.


Now if you replace my two large hills with many gently rolling hills, ones mileage can skyrocket to 100+. That is because you can glide down hills, using absoliyely no gas, and you can gently climb to the top of the next hill. The cycle repeats itself.

At 35MPH, you can climb a gentle hill at 50MPG instantaneous. When you glide down the hill your instantaneous is infinate because you are using no fuel. So assuming that half the time you are climbing at 50MPG, and the other half you are gliding at infinate MPG, you will achieve 100MPG. It just so happens that I have been lucky enough to have found such a course.

That is the best way that I can explain it.

Dan

 

Ray,
I was disappointed to see that this morning when I powered up, my gas gauge was down to one bar. And when I powered up for my trip home, I got the the Add Fuel warning and blinking last bar. Now I am about 25 miles into the blinking last bar with 852 miles, 85.5 MPG.

I remember you saying that you have 2 to 3 gallons after the blinking starts. In my only experience with running out of gas, I only got 112 miles at 85 MPG which works out to 1.2 gallons. I am obviously hoping that I have 2 gallons left. That is what I will need to reach 1000 miles.

Now, about getting 13 gallons into your tank.... Please explain the technique once again. For my current tank, I filled normally to the autostop and then was able to add the usual 1.2 gallons before the fuel level reached the top of the filler tube. Then I used a floor jack to raise the rear drivers side by about 8 inches. I was only able to add 1/4 gallon more.

Did I do anything wrong?

Thanks,

Dan

 

I got my first 600 mile tank today. I have a ways to go to get 700 or more. I stop filling the tank the when the nozzle clicks off the first time, but from 8 gal on I slow the fill rate to about a third of the normal rate. Still, I was really pleased to get 600 miles. My calculated mileage was 56.5 mpg and the MFD read 58.1 This tank lasted me 9 days, and my daily commute is about 30 miles each way - a mix of 65 mph interstate and 55 mph highway.

 

there is no secret to getting 85 mpg. it can be done and i have done it and you probably have to. are you going to tell me you never had a 5 min bar that was 85 mpg?

the only difference between us and him is that he is in a position where he doesnt have the need to get on the freeway and has a good route that is relatively "lightless and stopsignless" to travel.

it can be done, has been done, and you can do it to if you are willing to change your driving habits.

 

All I know is.......when I accelerate initially.....with an unwarmed-up engine............My mpg readings go to about 9mpg.....14mpg....some riduculous rate untill the car warms up a bit. And I'm not even pushing on the dam accelerator.

If you leave a light here in So Calif.....and are giving good effort with mild acceleration...... s l o w l y t r y i n g t o g e t u p t o 4 0 m i l e s p e r h o u r.........your still reading like 22mpg until you reach that plateau.
Additionally,.....people are totally pissed off around you......which can be fatal here.
I do try very hard to drive for efficient mpg.....and follow the advice shared here......but I'm choking on the concept of 80+mpg when I'm struggling with attaining 50.
Thanks for sharing some "hope".......I'll keep trying.
And Ray........I'm not cynical......I'm just looking for answers.

 

I've just crossed the 1288 km (800 miles) tank on my Classic 2K3 so 818 miles or more on a NHW20 is not unachievable. What would anyone gain by posting doctored photos?

On the Japanese 10/15 test cycle, the NHW20 achieves 35.5 km/l (83.5 MPG). With a 45 litre (11.9 Gallons) tank, the range can be up to 1597.5 km (993.7 miles). But please remembered that these test cycle are with stop-n-go traffic. If one were to drive nonstop at low speed and under favourable conditions, I believe they can achieve the 1200 miles.

Vincent

 

Push a bit harder on the accel. In all but the worst conditions, if you watch and slowly try to learn where the most efficient point is on acceleration, you should get about 25mpg on accel. Not only is this car great for telling us how to drive, if you pay enough attention during the engine run times, you'll find it'll tell you how efficently you're pushing the engine. Remember, engines do horrible when they aren't running at an optimal force - hence why regular cars idling is so rough on them (or their mileage, at least). Try faster accel at lights, see if it helps any. Practice and patience and forgetting everything you learned about driving previously are the best bets.

Here's what I usually do from a stoplight - usually, the amount I want to accelerate is faster than the car ahead of me. So, I'll use the battery only to accel to somewhere between 8-12 mph. Kind of along the lines on how semi trucks first accel, a little slow, but don't worry you'll make up for it soon. Then, when the car ahead of you has a decent amount of distance - or your engine kicks in while hitting that 8-12 mark, accelerate up to your cruising speed briskly - the engine is already running, use it to it's capacity. You'll find the people behind you are no longer upset at you because they are far behind, and you'll be caught up with the rest of traffic in no time. On average, on my daily commute where I know the roads by heart, my first 5 minute bar can regularly be around 37.5MPG or higher.

 

Ok, had to fill up this morning, they're changing my oil today and that'll hurt my mileage anyways.

Only reached 663 miles, 56.4MPG average for the tank. Pump clicked off at 11.1 gallons, filled to 12.3 gallons. This tank I'm hoping to break that ever elusive 60mpg mark for me.

-m.

 

thanks for the tips rflagg......

w00t..... This morning on my commute to work (12 miles and a brand spankin new tank of $2.45/gal fuel)......I'm showing 61.8mpg avg. :mrgreen:

On my initial "roll" out of the garage and my complex......I noticed one of my problems......
If the ICE is "ON"....and warming up.....and you don't push on the accelerator......your going to suffer.....about 8mpg on the MFD.....
I found that if I apply the accelerator at this warm-up time....this will engage the electric motor to work "with" the ICE and mpg jumps to like 25mpg on warm up.
Also, I'm still really not comfortable with my acceleration method while leaving stops....but I'll take rflagg up on his suggestion and experiment more.

 

Glad to hear, at least this morning, things went well! With all the focus to keep the engine off on this car the majority of the time, it's easy to forget this car can also teach you to drive efficiently when the engine is running. Best of luck this weekend - my weekend driving kills my mileage, just because of so many short trips - but let us know how it goes.

-m.

 

I'll reiterate what I was told several weeks ago. That the second-generation Prius shouldn't be run down to empty and should be refilled when you've used three quarers of a tank. This is because the fuel pump is located inside the tank and needs to be cooled by the gasoline. If you continuously run it down to empty, you'll burn out the fuel pump.

I'm one for running a car down to empty because, especially with small cars, the lower the tank goes, the better the mileage but after I heard this, I started refilling when there's a quarter of a tank left. Personally, I'd rather do that then have to go to the trouble of getting a fuel pump inside the gas tank replaced.

 

I am under the impression that deadband acceleration, and then using deadband + gliding to keep the MPH between about 30 and 40 is the most efficient way to drive. That means using the battery at little as possible (no arrows to or from), which can seem counter-intuitive.

The reason for this is simply because transferring energy to the battery and out again is not 100% efficient so it's best to use the ICE to power the wheels directly. Of course it's not possible to drive this way all the time, and that's why there's a battery.

Please correct me if I'm wrong about this.

Best of luck to the Extreme Mileage gang next weekend!

 

Well the %^*%$@ last bar has been flashing at me for nearly 80 miles now. I pulled into the garage tonight with 905 miles, 85.3MPG. I have to go into work tomorrow so I expect to hit 1000 by Sunday as long as the fuel holds out.

Dan

 

deh2k, I couldn't have said it any better!

Thanks for the kind wishes. We will need all of the help we can get!

Dan