What's your fuel economy to weight ratio?

[JanGeo]

Originally Posted by thisisntjared

did anyone read my post??? what the piss?

You nailed it - tough being right isn't it! I has to be a product because it then becomes an efficency measurement. Now lets throw in frontal area too.

[Compaq888]

Originally Posted by thisisntjared

did anyone read my post??? what the piss?

I read it but your theory was too much for my brain at 3am your greatness.

[Silveredwings]

Originally Posted by thisisntjared

would the measure of efficiency be the mpg multiplied by the weight then divided by some constant? the efficiency to weight ratio doesnt really say anything...

see:
with driver:
40/2300 = .01739
without:
40/2130 = .01878

and are we doing this with or without the driver?

anyway i think we should divide by 1000. its funny cus now you cant call it a ratio. product?? haha the efficiency to weight product.

with driver:
40*2300/1000 = 92
without:
40*2130/1000 = 85.2

So what you're describing is pound-miles per gallon. It goes up with weight, and it goes up with raw mpg. In other words, it's the average number of miles your car can drag each pound per gallon.

Raw mpg is still impressive, this is just another statistic. If you can get a heavy vehicle to get a large number, then it says something.

example - light car vs. heavy car:
30 mpg * 1800# / 1000 = 54
30 mpg * 3200# / 1000 = 96

(that 1800# car would have to get over 53 mpg to get to this number - as some of you do!).

The correlation between the utility of a vehicle and it's weight merits a thread of its own. Or maybe you can multiply by the average 'occupant seat-miles' of actual usage.

[Compaq888]

we should definetly figure out some kind of a formula for weight and mpg. Because some of us don't have 3 cylenders, lightweight car, manual transmission, honda engine, small displacement motor. With the formula with can show who made more progress. Of course the thing under our sigs that showed a % hypermiling was accurate too.

[MetroMPG]

Originally Posted by Compaq888

Actually power to weight is done differently. It's the biggest number divided by the smaller number.

That's weight to power. It can be done either way: power to weight ratio - Wikipedia

I don't really mind which formula we use for efficiency and weight, or whether the figure rises or declines relative to efficiency. The interesting information comes from comparing multiple vehicles as long as we're using the same formula.

In lb-miles per gallon, the Fireflea is:

1800# * 59.3 / 1000 = 108.519

JanGeo suggests factoring in frontal area as well, though it would be more accurate if you factored in CdA rather than just A.

[thisisntjared]

finally people are responding anyway are we doing this with or without drivers?

also, metro, could you take everyones statistics and put them in the first post of the thread? like to consolidate the information?

adding the frontal area or cd or both could be too much. in the end your just factoring them out. but if a higher number is better then you want to multiply the number we came up with by the product of the frontal area and the cd. the problem is that most of us no longer have the cd that our cars came with from the factory. so maybe just frontal area and well will then have our generalized number for the efficiency of the drivetrain and aerodynamics. in the end these are the things that all of us tend to modify anyway right?

i think it would be cool to see the significance of the statistics. the efficiency-weight product and efficiency-weight-size product next to each other for each car.

[GasSavers_katman]

Originally Posted by Compaq888

we should definetly figure out some kind of a formula for weight and mpg. Because some of us don't have 3 cylenders, lightweight car, manual transmission, honda engine, small displacement motor. With the formula with can show who made more progress. Of course the thing under our sigs that showed a % hypermiling was accurate too.

Yes I agree! Some of us have SUVs and full size V-8 cars and trucks. I think we need our own section on the Forum for Full Size, Trucks, SUVs, and Cars with V-8s!!!

[MetroMPG]

Originally Posted by thisisntjared

finally people are responding anyway are we doing this with or without drivers?

Let's do it without drivers.

I'll compile a summary in the top post in a day or so when more people have had time to respond.

[95metro]

Sorry for being dense, but I can't wrap my brain around that lb-mile per gallon number. It doesn't make any sense to me at all. I can understand people wanting more credit based on the type of vehicle they drive, but wouldn't a point system make more sense than a single screwball measurement?

[thisisntjared]

Originally Posted by katman

Yes I agree! Some of us have SUVs and full size V-8 cars and trucks. I think we need our own section on the Forum for Full Size, Trucks, SUVs, and Cars with V-8s!!!

thats worth pondering. i have a feeling its a good suggestion for the future as this site grows and by that i mean as the cost of gas goes up but the value of the big v8s wont return enough to justify selling it in place for the gas sipper.

i bet there are a lot of things that can be done to the bigger cars that havent been thought about just because there are not many minds out there that would think to do so.

<--*continues to ponder*