Lifetime Miles Per Gallon (LMPG)

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#11

12-14-2005, 05:31 AM

Civic Duty

Brains of the Operation

Join Date: Jun 2005

Posts: 226

Re: Lifetime Miles Per Gallon (LMPG)

Wow, great idea. Thanks!

Also, as long as the super cold temperatures keep away from South Carolina, you'd better watch out pretty soon for a new 05 HCH on the hypermiler rolls.

#12

12-14-2005, 07:06 AM

Tim

Enchanter, Enthusiast

Join Date: May 2004

Location: Seattle, Washington

Posts: 852

Re: Lifetime Miles Per Gallon (LMPG)

Quote:

Originally Posted by Civic Duty

I think I'm going to just start using the FCD readouts for my mileage entries on the database rather than losing gas receipts (which I do a lot) and worrying about the number. Would I lose GreenHybrid cred for doing that? Wayne?

I know everyone has different experiences with this, but I've been tracking the FCD error margin for 25 tanks now. Over that time, it's off an average of +3.1 MPG (over estimates). The worst error margin was +5.1 MPG. It's never been exact or under. I know we strive for accuracy in the database as a means to occassionally combat the nonsense coming from Consumer Reports and the like. There are probably enough cars and tanks in the database where using FCD values would not influence the overall outcome, but it does introduce a bit of an error IMO.

#13

12-14-2005, 07:14 AM

tbaleno

Join Date: Dec 2004

Location: Leominster, MA

Posts: 2,161

Re: Lifetime Miles Per Gallon (LMPG)

Hand calcs on my car show a definite optimistic reading. Usualy about 5mpg high. Never does the FCD show less mileage or equal milage than my hand calcs.

#14

12-14-2005, 07:18 AM

Delta Flyer

Banned

Join Date: Apr 2005

Location: Lewisville (Dallas), Texas

Posts: 3,155

A Thought

Even if the FCD is off, my guess is it would be more consistent than manually checking the milage. I just don't have a lot of faith that the gas pump cut off is going to be consistent.

#15

12-14-2005, 09:30 AM

CGameProgrammer

Geek

Join Date: Mar 2005

Location: San Diego

Posts: 839

Re: A Thought

Quote:

Originally Posted by Delta Flyer

Even if the FCD is off, my guess is it would be more consistent than manually checking the milage. I just don't have a lot of faith that the gas pump cut off is going to be consistent.

And while that introduces slight inaccuracies on a single-tank basis, it still ensures total accuracy for lifetime mileage. If you use go 500 miles and use 10 gallons, but pump 9.9 before click-off, your calculated tank mileage would be 0.5 mpg too high. But it'll even on on the next tank; you may pump 10 gallons but find you only went 495 miles, resulting in a tank mileage 0.5 MPG too low, since there were really just 9.9 gallons in the tank.

In any case, we know the FCD can be inaccurate to a larger degree, and topping off is a really bad habit, especially because it releases alot of pollution. So pump to click-off and be done with it.

Last edited by CGameProgrammer; 12-14-2005 at 09:32 AM.

#16

12-14-2005, 11:58 AM

xcel

Ridiculously Active Enthusiast

Join Date: Feb 2004

Location: Northern Illinois

Posts: 2,567

Re: Lifetime Miles Per Gallon (LMPG)

Hi Civic Duty:

___You will be there soon enough

___Delta_Flyer, after multiple tanks, the first click shutoff will not matter as your actual miles traveled over gallons pumped will give you the actual. I found the Insight’s lmpg to be practically dead on with the hand calc’s although a vapor recovery fill threw out the individual tank(s) when that happened

___Good Luck

___Wayne R. Gerdes