March 2007 Averages

**Tideland Prius** · 03-09-2007, 02:44 AM

Total Miles: 43924kms
Tank Miles: 629.4km

MFD Avg: 4.6L/100km
Calc'd Avg: 5.04L/100km

Fuel Added: 31.741 litres
Cost: 31.87

Price per litre: $1.04

barbaram · 03-12-2007, 02:07 AM

I'm finally catching up with things...starting reseting each tank in Feb when I hit 20,000 miles-

3/6/2007 216.2 mile 4.479 gal 48.2697 MFD showed 43.8......

mrjpaterson · 03-12-2007, 10:50 PM

<div class='quotetop'>QUOTE(Tideland Prius @ Mar 9 2007, 03:44 AM) [snapback]402699[/snapback]</div>

Quote:

Total Miles: 43924kms
Tank Miles: 629.4km

MFD Avg: 4.6L/100km
Calc'd Avg: 5.04L/100km

Fuel Added: 31.741 litres
Cost: 31.87

Price per litre: $1.04
[/b]

Ok. What I don't really understand is the apparently very large discrepancy between calculated mileage and MFD display! Since the purchase of my Prius about a month ago I've filled up two times, with the first saying 5.1L/100km (or 46.11mpg US) and the second saying 5.0L/100km (or 47.04 mpg) on the MFD. But when I calculated the amount of kilometers driven divided by the amount of gas added I get far from these figures. Both times it averaged out to something like 5.5L/100km (or 42.76) and 5.65L/100km ( or 41.62 mpg). Isn't it a bit off to be more than 10% whacky? I've read people saying 2 mpg off, but this seems suspect. Am I really the only one who is finding this big of a gap? Am I math dumb? Or am I missing some basic concept of how to calculate tank mileage?

I do realize that two tanks may not be enough to judge by, but is there anything else that I could take into consideration? And before anyone replies, I do know about filling the tank slowly, and this is perhaps the reason I was able to get in 39 liters the first time and 37 liters the second time.

Thanks to all that take the time to share their experience!

JP

<div class='quotetop'>QUOTE(Great White North @ Mar 12 2007, 10:47 PM) [snapback]404576[/snapback]</div>

Quote:

Ok. What I don't really understand is the apparently very large discrepancy between calculated mileage and MFD display! Since the purchase of my Prius about a month ago I've filled up two times, with the first saying 5.1L/100km (or 46.11mpg US) and the second saying 5.0L/100km (or 47.04 mpg) on the MFD. But when I calculated the amount of kilometers driven divided by the amount of gas added I get far from these figures. Both times it averaged out to something like 5.5L/100km (or 42.76) and 5.65L/100km ( or 41.62 mpg). Isn't it a bit off to be more than 10% whacky? I've read people saying 2 mpg off, but this seems suspect. Am I really the only one who is finding this big of a gap? Am I math dumb? Or am I missing some basic concept of how to calculate tank mileage?

I do realize that two tanks may not be enough to judge by, but is there anything else that I could take into consideration? And before anyone replies, I do know about filling the tank slowly, and this is perhaps the reason I was able to get in 39 liters the first time and 37 liters the second time.

Thanks to all that take the time to share their experience!

JP
[/b]

...and then of course I look back at Tidelands figures and realize that he is 10% off with the 4.6 to 5.04 gap as well. So...um...is it only us two then? (he added sheepishly...)

**Tideland Prius** · 03-13-2007, 01:47 AM

<div class='quotetop'>QUOTE(Great White North @ Mar 12 2007, 08:50 PM) [snapback]404576[/snapback]</div>

Quote:

Ok. What I don't really understand is the apparently very large discrepancy between calculated mileage and MFD display! Since the purchase of my Prius about a month ago I've filled up two times, with the first saying 5.1L/100km (or 46.11mpg US) and the second saying 5.0L/100km (or 47.04 mpg) on the MFD. But when I calculated the amount of kilometers driven divided by the amount of gas added I get far from these figures. Both times it averaged out to something like 5.5L/100km (or 42.76) and 5.65L/100km ( or 41.62 mpg). Isn't it a bit off to be more than 10% whacky? I've read people saying 2 mpg off, but this seems suspect. Am I really the only one who is finding this big of a gap? Am I math dumb? Or am I missing some basic concept of how to calculate tank mileage?

I do realize that two tanks may not be enough to judge by, but is there anything else that I could take into consideration? And before anyone replies, I do know about filling the tank slowly, and this is perhaps the reason I was able to get in 39 liters the first time and 37 liters the second time.

Thanks to all that take the time to share their experience!

JP
...and then of course I look back at Tidelands figures and realize that he is 10% off with the 4.6 to 5.04 gap as well. So...um...is it only us two then? (he added sheepishly...)
[/b]

Don't forget we're heading towards spring so the temperatures are getting warmer which means the bladder is expanding which means we can add more fuel into the tank each time we refuel.

I'm not too bother about the miscalculations since I know they'll average out. My lifetime avg is 5.1L/100km. My lifetime MFD avg is 4.84L/100km so it's close enough.

Also, I can tell there's more fuel in the tank and the bladder is expanding because I'm able to go further before the 1st pip disappears. The last tank, it disappeared around 78kms. This time, it's 110kms even though my mileage is worse (currently sitting at 5.0L/100km).

mrjpaterson · 03-14-2007, 02:03 AM

<div class='quotetop'>QUOTE(Tideland Prius @ Mar 13 2007, 01:47 AM) [snapback]404702[/snapback]</div>

Quote:

Don't forget we're heading towards spring so the temperatures are getting warmer which means the bladder is expanding which means we can add more fuel into the tank each time we refuel.

I'm not too bother about the miscalculations since I know they'll average out. My lifetime avg is 5.1L/100km. My lifetime MFD avg is 4.84L/100km so it's close enough.

Also, I can tell there's more fuel in the tank and the bladder is expanding because I'm able to go further before the 1st pip disappears. The last tank, it disappeared around 78kms. This time, it's 110kms even though my mileage is worse (currently sitting at 5.0L/100km).
[/b]

Wow. My first "pip"/bar hasn't disappeared yet for this tank and I'm at 157km. These things are really inconsistent. Still love the car though.
And yes, I didn't really consider the fact that the bladder could hold more fuel with the warmer temperatures. This was the information I was looking for. Thx again.

**Tideland Prius** · 03-14-2007, 01:26 PM

<div class='quotetop'>QUOTE(Great White North @ Mar 14 2007, 12:03 AM) [snapback]405239[/snapback]</div>

Quote:

Wow. My first "pip"/bar hasn't disappeared yet for this tank and I'm at 157km. These things are really inconsistent. Still love the car though.
And yes, I didn't really consider the fact that the bladder could hold more fuel with the warmer temperatures. This was the information I was looking for. Thx again.
[/b]

whoa... 157km would be what I get in the summer!! They must've changed the bladder to a more flexible version haha.

spudnique · 03-21-2007, 01:05 AM

I'm averaging about 5.3 L/100km for March. We had weather down to -20C for a week or so. I blocked the front with pipe insulation (2 stripes on the top and 2 on the bottom) so I didn't notice when the temp dropped from -10C to -20C. I've only done 4 fill-ups though, having an odometer reading of 2700km. I'm only able to fit around 32L of gas once the last bar starts to blink.

I hope it picks up in the good weather. I'm not anywhere near the 'official' consumption.

**Tideland Prius** · 03-21-2007, 02:38 AM

<div class='quotetop'>QUOTE(spudnique @ Mar 20 2007, 11:05 PM) [snapback]409428[/snapback]</div>

Quote:

I'm averaging about 5.3 L/100km for March. We had weather down to -20C for a week or so. I blocked the front with pipe insulation (2 stripes on the top and 2 on the bottom) so I didn't notice when the temp dropped from -10C to -20C. I've only done 4 fill-ups though, having an odometer reading of 2700km. I'm only able to fit around 32L of gas once the last bar starts to blink.

I hope it picks up in the good weather. I'm not anywhere near the 'official' consumption.
[/b]

5.3 is really good for that kind of temperatures. A "normal" west coast driver would get 5.6L/100km in the summer time!

Also, 32L in the middle of winter is about right. It's pretty impressive if that was in -20°C weather. Last summer, when I got my record tank, I squeezed in 38 litres only.

**TonyPSchaefer** · 03-21-2007, 08:56 AM

Pulled into work parking lot this morning. I experimented with a new route. It's out of my way, taking my off my normal direct-shot drive. I can't say for certain that it's a better route because it's 37F and raining this morning, but it felt better. Fewer stoplights and a more moderate average speed, that's for sure.

Current tank miles: 370
Current tank mileage: 55.7

Charles Suitt · 03-21-2007, 11:49 AM

<_< For over 2½ years, I have kept "tank by tank" records on my original '04 Prius and now my '07 touring Edition. I have found that the MFD is more than 98% accurate when compared to the pumped fuel/miles traveled. A single tank comparison cannot provide an accurate result. My accuracy is over MANY fuelings.

>98% is "close enough for government work" for me.

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03-09-2007, 02:44 AM	#1
Tideland Prius Super Moderator Join Date: Oct 2004 Location: Canada Posts: 14,192 My Car: 2005 Prius Package: B Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 12	Total Miles: 43924kms Tank Miles: 629.4km MFD Avg: 4.6L/100km Calc'd Avg: 5.04L/100km Fuel Added: 31.741 litres Cost: 31.87 Price per litre: $1.04

03-12-2007, 02:07 AM	#2
barbaram Senior Member Join Date: Jan 2006 Location: Trenton, NJ Posts: 721 My Car: 2006 Prius Package: #6 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I'm finally catching up with things...starting reseting each tank in Feb when I hit 20,000 miles- 3/6/2007 216.2 mile 4.479 gal 48.2697 MFD showed 43.8......

03-21-2007, 01:05 AM	#7
spudnique Join Date: Feb 2007 Location: montreal, quebec Posts: 13 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I'm averaging about 5.3 L/100km for March. We had weather down to -20C for a week or so. I blocked the front with pipe insulation (2 stripes on the top and 2 on the bottom) so I didn't notice when the temp dropped from -10C to -20C. I've only done 4 fill-ups though, having an odometer reading of 2700km. I'm only able to fit around 32L of gas once the last bar starts to blink. I hope it picks up in the good weather. I'm not anywhere near the 'official' consumption.

03-21-2007, 08:56 AM	#9
TonyPSchaefer Ruler of Omicron Persei 8 Join Date: May 2004 Location: Far-North Chicagoland Posts: 8,644 My Car: 2004 Prius Package: #9 Nominated 4 Times in 2 Posts TOTM Awards: 0 Friends: 18	Pulled into work parking lot this morning. I experimented with a new route. It's out of my way, taking my off my normal direct-shot drive. I can't say for certain that it's a better route because it's 37F and raining this morning, but it felt better. Fewer stoplights and a more moderate average speed, that's for sure. Current tank miles: 370 Current tank mileage: 55.7

03-21-2007, 11:49 AM	#10
Charles Suitt Senior Member Join Date: Oct 2004 Location: Dallas TX Posts: 1,622 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	<_< For over 2½ years, I have kept "tank by tank" records on my original '04 Prius and now my '07 touring Edition. I have found that the MFD is more than 98% accurate when compared to the pumped fuel/miles traveled. A single tank comparison cannot provide an accurate result. My accuracy is over MANY fuelings. >98% is "close enough for government work" for me.