Gas mileage

[skace]

I don't know about the rest of you retards, but I'd get the 12,000 mpg vehicle.

 

[PlasmaBomb]

Originally posted by: Engineer

Originally posted by: nakedfrog

Originally posted by: Turin39789
where does my bicycle fit into the equation?

Well, as you get 0 gallons per mile (or 0 miles per gallon, if you prefer) any vehicle is a huge improvement as far as gas mileage goes.

It's actually infinite (or undefined) miles per gallon as it would be ZERO gallons...

miles / ZERO = undefined (infinity as gallons approaches zero)...

FAIL

The answer is zero (or pretty darn close) think about it...

 

[seemingly random]

The percentage concept also explains why the increase in fuel prices is affecting lower income folks so much more than others.

 

[sswingle]

Originally posted by: JEDI

Originally posted by: DrPizza
I heard something similar to this on NPR the other day, and thought it was worth repeating here. Ultimately, I find that the problem relates to people going with their intuition, rather than their desire to do the math (and often, a lack of mathematical ability.) And, unfortunately, "uninformed" public opinion sometimes drives political policy making, which often overlooks more important sides of issues.

This concerns gas mileage: (I remembered this in a furnace efficiency thread where 80% may be cheaper in the long run than 95% efficient)

Suppose a married couple has two vehicles; and each is driven about the same number of miles each year - 12,000 miles. The husband drives (and requires) a truck; and his only gets about 15mpg. The wife has a nice smaller car that gets about 27mpg. The couple decides that they can afford payments on one new vehicle, thus they'll be able to replace only one of the two that they currently own. The choices are to replace the 15mpg truck with a 21mpg truck, or to replace the 27mpg car with a 39mpg car. And, they realize that for just a little bit more money, they might even be able to swing the payments on a 51mpg hybrid, rather than a 39mpg car. What should they do?

Well, most people's intuitions would tell them, "get the hybrid you idiots, that's 23mpg more!" And, while some of you might have done the math in your heads, I'm sure that some of you realize that the hybrid people are wrong, else I wouldn't have written this thread. Thank you for your trust.

Ask this question of most people though, and they'd think it was a no-brainer. You only gain 6mpg with the truck, compared to gaining 12mpg for the car. Or, gaining 23mpg for the hybrid, almost doubling the current mpg!!!

The math: For 12,000 miles, the amount of gas each uses in a year:
15mpg: 800 gallons
21mpg: 571.4 gallons
27mpg: 444.4 gallons
33mpg: (I know, this wasn't an option) 363.6 gallons
39mpg: 307.7 gallons.
45mpg: 266.7 gallons
51mpg: 235.3 gallons

Notice: there isn't a linear relationship between the mpg you gain, and the gallons you save. Going from 15mpg to 21mpg saves 228.6 gallons (This is what upgrading the truck gets you.) Going from 21 to 27 (which wasn't an option) saves only 127 gallons. Going from 27 to 33 saves even less: 76.4 gallons, and 33 to 39 saves only 55.9 gallons. From 39 to 45: 40 gallons, and from 45 to 51: 31.4 gallons.

So, switching from a 15mpg truck to a 21 mpg truck makes much more sense (saves 228.6 gallons) than going from 27mpg to 39mpg (saves 136.7 gallons) And, it still makes more sense than even switching from the 27mpg car to the 51mpg hybrid (which would save 209.1 gallons)

Also worth noting: The difference between a 51mpg hybrid, and a magical 100mpg dream vehicle would "only" save 115.3 gallons of gas a year. That's less gas savings than going from 21mpg to 27mpg. Going from that magical 100mpg vehicle to the absolutely insane 12,000mpg vehicle would save 119 gallons of gas. And, that's even less than the savings in going from 21mpg to 27mpg.

For those of you who drive trucks, large vans, SUV's, etc., (many not because they have a choice of what type of vehicle they own) realize how much of an effect 2 or 3 mpg due to better maintenance can have on your mileage. As a nation, we'd probably save more gas by encouraging the owners of "gas guzzlers" to maintain their vehicles better, than by mandating some arbitrary increase in required average gas mileage by the manufacturers.

thank you for the analysis.

never realized that. :Q

always thought of cost analysis of new car price vs cost of driving old car and where the breakeven point is. (Lexus SUV hybrid breakeven is in DECADES :Q you only gain 1mpg w/it's hybrid.)

The point of the Lexus hybrid is not gas savings, its more power. Lexus makes this quite clear.

 

[Throckmorton]

Originally posted by: ElFenix
which is why hybrid trucks rock.

Name one actual hybrid truck. You know the Silverado isn't a real hybrid right? It only has a big alternator for accessories.

 

[dmcowen674]

Originally posted by: ICRS

Originally posted by: dmcowen674
Big Oil pay you for that disertation?

We should not be using ICE period.

Then what should we use.

Their is nothing practicle on the market now that doesn't use a ICE.

That's the point. We have had since 1973 to get off of ICE and Oil.

 

[Fritzo]

We went from 16mpg to 28 mpg. What's that save us?

 

[Zenmervolt]

Originally posted by: dmcowen674

Originally posted by: ICRS

Originally posted by: dmcowen674
Big Oil pay you for that disertation?

We should not be using ICE period.

Then what should we use.

Their is nothing practicle on the market now that doesn't use a ICE.

That's the point. We have had since 1973 to get off of ICE and Oil.

The ICE is a fantastic piece of technology. The issue is simply coming up with a different fuel source. Personally, I'm a fan of turbines (which are still, technically ICEs). They can run on just about any flammable liquid. You can pour pretty much anything from peanut oil to Old Granddad into the tank and a turbine will burn it. Mileage is terrible for cars, but that doesn't really matter if you can choose pretty much anything to burn.

Of course, going to external combustion would be neat too. I'd love to see someone try a return to steam (torque, torque, and more torque). Something like the Doble would be great. With modern manufacturing and materials the drawbacks could be essentially eliminated and, like the turbine engines, it could burn just about any flammable liquid.

I'm not at all convinced that battery powered electric cars will ever be truly viable. They just cannot be refueled fast enough. There's no way you could manage an 800 to 1000 mile one-day trip in a battery-powered electric car.

ZV

 

[Aikouka]

Originally posted by: 2Xtreme21
While I don't disagree with the OP, I want to show the large flaw in basing decisions on purely percentage:

If my hourly earnings increased from $10 to $18, I got an 80% raise.

If my hourly earnings increased from $1000 to $1500, I only got a 50% raise.

If you look at it in purely percentage terms, the $10 -> $18 person got a better deal than the $1000 -> $1500. What people neglect is an equal frame of reference.

I don't look at what he wrote as "basing decisions purely on percentage." If that were true, then he'd say something dumb like this:

"Well, it's the same going from 15 to 30mpg as it is going from 30 to 60mpg!"

'cause guess what? In both cases you're halving your consumption, which results in a 50% decrease in gallons used. The real point is to look at the actual numbers which you'd see -400 gallons compared to -200 gallons.

 

[Nyati13]

Originally posted by: ducci

Originally posted by: Nyati13

Originally posted by: DrPizza
The husband drives (and requires) a truck; and his only gets about 15mpg.

I know for this example it's a given that the truck is required, but honestly 8 or 9 out of every 10 people who claim they "need" a truck don't actually need one.

Sooo... replace "needs" for "wants" and the argument remains valid.

"want" is in a much lower bracket in a budget than "need". If people were actually honest with themselves, they could open up a lot of financial freedom for themselves if they would just accurately classify "wants" and "needs".

 

[oznerol]

Geez, people, as said already all you need to do is take the inverse of the MPG number to get GPM - so 19MPG = 1/19 GPM.

If you think of it that way, its very simple. The greater the number gets, the tinier the inverse, and thus the smaller change. You don't need to be an engineer to get this (or maybe you do?)

 

[oznerol]

Originally posted by: Nyati13

Originally posted by: ducci

Originally posted by: Nyati13

Originally posted by: DrPizza
The husband drives (and requires) a truck; and his only gets about 15mpg.

I know for this example it's a given that the truck is required, but honestly 8 or 9 out of every 10 people who claim they "need" a truck don't actually need one.

Sooo... replace "needs" for "wants" and the argument remains valid.

"want" is in a much lower bracket in a budget than "need". If people were actually honest with themselves, they could open up a lot of financial freedom for themselves if they would just accurately classify "wants" and "needs".

I definitely agree - but regardless of whether or not the truck is a "want" or a "need" the math remains the same - and that was my only point. Necessity isn't relevant in this argument, so "wants" and "needs" are interchangeable.

 

[Zenmervolt]

Originally posted by: Nyati13

Originally posted by: ducci

Originally posted by: Nyati13

Originally posted by: DrPizza
The husband drives (and requires) a truck; and his only gets about 15mpg.

I know for this example it's a given that the truck is required, but honestly 8 or 9 out of every 10 people who claim they "need" a truck don't actually need one.

Sooo... replace "needs" for "wants" and the argument remains valid.

"want" is in a much lower bracket in a budget than "need". If people were actually honest with themselves, they could open up a lot of financial freedom for themselves if they would just accurately classify "wants" and "needs".

I just have a few questions: How large was the survey of people you sampled to determine that "8 or 9 out of every 10 people who claim they "need" a truck don't actually need one."? Where and when was the survey conducted and what normalization methodology did you use? What criteria did you use to define "need" and how did you evaluate a respondent's lifestyle to determine whether or not those criteria were met? How did you determine that your assessment of "need" had greater validity than the respondents' assessments?

Or did you just pull those numbers out of your arse?

Thought so.

ZV