Magic Numbers

fruzzetti · 12-05-2007, 05:20 PM

Hi all. I'm new to the forums; I have had several hits from search engines and other links (I do a lot of modifications to my cars as a hobby), and I've lurked off and on for a while, but I finally decided I'd join on. For my first thread I'd like to start a discussion of the magic numbers - the "gateway" speeds at which different effects abruptly manifest themselves for the Prius.

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Definitions
Though this is a simplification, I found there were several magic numbers:

City Number (C): The maximum speed at which you can maintain minimal engine use over the longest distances (faster than this and you're going to be using the engine substantially more).

Highway Number (H): The maximum speed you can drive before mileage drops off quickly (faster than this and your mileage takes a severe hit).

Battery Number (

: The maximum speed you can generally drive and still have the car maintain a charge in the battery (after this speed the car struggles to maintain a healthy battery state; I consider this somewhat unsustainable for that reason).

Governed Maximum Speed (M): The highest speed the car will allow itself to move under normal (level-ground), all-stock conditions.

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MkI - 2001-2003
I drove a white 2001 for four years, netting 95 000 miles on it. When I traded it in it had a lifetime average of 53.5MPG.

Anecdote: Knowing one shouldn't count drives shorter than 10 miles or 15 minutes, I'd say my best mileage drive ever was on Valentine's day 2003, when I drove 45 miles from Pleasanton to Vallejo, CA with an overall score of 81.3 MPG. The traffic was bumper to bumper, it was freakishly hot (85-90F) and I decided to rough it with the windows down and the AC off, driving the car as though I were playing a video game. I have never repeated such a great result over such a long distance.

In this car I found the following:

C = 26mph / 42kph
H = 53mph / 85kph
B = 81mph / 130kph
M = 102mph / 164kph

MkII - 2004-2006

So far I've gone 21 000 in my 2006. I'm not tracking the lifetime mileage this time, because every fresh tank I try very hard to beat my old high score

Anecdote: My best single run in the car was 345 miles from Hayward to Northridge, CA nonstop on a midday - afternoon in late summer 2006. I scored 62.1MPG here. Though I can routinely beat this score in 10-20 mile runs pretty much any time, I consider this particular run marvelous as I made no sacrifices other than driving speed on that day.

C = 32mph / 51kph
H = 61mph / 98kph
B = >90mph / 145kph *
M = >99mph / 159kph *

* I haven't had the combination of guts and opportunity to sustain speeds above 90mph for any real length of time in this car, so I can't support any claims about them. If you know for sure what these speeds are, please forward them in.

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Remember that my experience is limited to one sample of each car. If you demand photographic evidence, I am pretty sure I can come up with all of it (I take a LOT of pictures of all sorts of things, so it's more a question of sifting through 60GB of photos to find the right ones than a question of whether I took photos to begin with).

If you have corrections or more accurate figures, please forward them. If you have questions about methods or techniques, please ask.

Thanks, and I'm very glad to have joined the forums!

~ dan ~

hobbit · 12-05-2007, 06:00 PM

wow, you owned a Pri for that long without being on the forums?
That's its own kind of impressive...
.
Nice numbers on some of your segments. See CleanMPG for
some other folks who like playing the video game down to the
smallest detail.
.
I'm not sure you can declare hard points for some of what you
were asking about. For instance, highway MPG doesn't have a
sharp cutoff knee, it's a fairly smooth continuum over a range
of speeds [but starts to hit you as a cubic result above 60 mph
or so]. The engine-on/engine-off is pretty well known at 42.
Other than that it's so subject to ambient conditions and the
skill of the commanding foot, you can't really nail it...
.
_H*

fruzzetti · 12-05-2007, 07:10 PM

LOL true that, hobbit. It's probably because I'm a native Californian, and the "weather" here is pretty mild. I agree about what you've said, and should add that my numbers have been very accurate (verified through my experiences in only the two cars) in warmer weather. I wouldn't discuss cooler-weather performance because, as we all know, performance takes a major hit.

~ dan ~

12-05-2007, 05:20 PM	#1
fruzzetti Customization-Obsessed Join Date: Dec 2007 Location: Hayward, CA USA Posts: 337 My Car: 2006 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Magic Numbers Hi all. I'm new to the forums; I have had several hits from search engines and other links (I do a lot of modifications to my cars as a hobby), and I've lurked off and on for a while, but I finally decided I'd join on. For my first thread I'd like to start a discussion of the magic numbers - the "gateway" speeds at which different effects abruptly manifest themselves for the Prius. ----- Definitions Though this is a simplification, I found there were several magic numbers: City Number (C): The maximum speed at which you can maintain minimal engine use over the longest distances (faster than this and you're going to be using the engine substantially more). Highway Number (H): The maximum speed you can drive before mileage drops off quickly (faster than this and your mileage takes a severe hit). Battery Number (: The maximum speed you can generally drive and still have the car maintain a charge in the battery (after this speed the car struggles to maintain a healthy battery state; I consider this somewhat unsustainable for that reason). Governed Maximum Speed (M): The highest speed the car will allow itself to move under normal (level-ground), all-stock conditions. ----- MkI - 2001-2003 I drove a white 2001 for four years, netting 95 000 miles on it. When I traded it in it had a lifetime average of 53.5MPG. Anecdote: Knowing one shouldn't count drives shorter than 10 miles or 15 minutes, I'd say my best mileage drive ever was on Valentine's day 2003, when I drove 45 miles from Pleasanton to Vallejo, CA with an overall score of 81.3 MPG. The traffic was bumper to bumper, it was freakishly hot (85-90F) and I decided to rough it with the windows down and the AC off, driving the car as though I were playing a video game. I have never repeated such a great result over such a long distance. In this car I found the following: C = 26mph / 42kph H = 53mph / 85kph B = 81mph / 130kph M = 102mph / 164kph MkII - 2004-2006 So far I've gone 21 000 in my 2006. I'm not tracking the lifetime mileage this time, because every fresh tank I try very hard to beat my old high score Anecdote: My best single run in the car was 345 miles from Hayward to Northridge, CA nonstop on a midday - afternoon in late summer 2006. I scored 62.1MPG here. Though I can routinely beat this score in 10-20 mile runs pretty much any time, I consider this particular run marvelous as I made no sacrifices other than driving speed on that day. C = 32mph / 51kph H = 61mph / 98kph B = >90mph / 145kph * M = >99mph / 159kph * * I haven't had the combination of guts and opportunity to sustain speeds above 90mph for any real length of time in this car, so I can't support any claims about them. If you know for sure what these speeds are, please forward them in. ----- Remember that my experience is limited to one sample of each car. If you demand photographic evidence, I am pretty sure I can come up with all of it (I take a LOT of pictures of all sorts of things, so it's more a question of sifting through 60GB of photos to find the right ones than a question of whether I took photos to begin with). If you have corrections or more accurate figures, please forward them. If you have questions about methods or techniques, please ask. Thanks, and I'm very glad to have joined the forums! ~ dan ~

12-05-2007, 06:00 PM	#2
hobbit Senior Member Join Date: Mar 2005 Location: Bahstahn Posts: 3,012 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	wow, you owned a Pri for that long without being on the forums? That's its own kind of impressive... . Nice numbers on some of your segments. See CleanMPG for some other folks who like playing the video game down to the smallest detail. . I'm not sure you can declare hard points for some of what you were asking about. For instance, highway MPG doesn't have a sharp cutoff knee, it's a fairly smooth continuum over a range of speeds [but starts to hit you as a cubic result above 60 mph or so]. The engine-on/engine-off is pretty well known at 42. Other than that it's so subject to ambient conditions and the skill of the commanding foot, you can't really nail it... . _H*

12-05-2007, 07:10 PM	#3
fruzzetti Customization-Obsessed Join Date: Dec 2007 Location: Hayward, CA USA Posts: 337 My Car: 2006 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	LOL true that, hobbit. It's probably because I'm a native Californian, and the "weather" here is pretty mild. I agree about what you've said, and should add that my numbers have been very accurate (verified through my experiences in only the two cars) in warmer weather. I wouldn't discuss cooler-weather performance because, as we all know, performance takes a major hit. ~ dan ~