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cars and fuel efficiency

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cars and fuel efficiency

15 Aug 2017 14:33

i was looking for an existing thread to post this, but all my searches on 'cars' , 'gas mileage' etc lead to the us politics thread :rolleyes: no kidding. hence a new thread... if the mods find a more appropriate thread, by all means, merge it, transfer whatever...

anyways. just returned from a trip across the us southwest - mostly arizona and new mexico. we rented KIA Forte in phoenix. frankly, i wanted something bigger to better fit my rather long frame, but missus python won the day with a killer argument - she said i could chill in the reclined passenger seat as long as she wasn't excessively tired.

...an so it went for 2 weeks... free of driving and navigation (thanks to gps) i mostly marveled at the mountains, made pictures, kept some small convo for company...i even sipped beer being a passenger. considering that i put the entire trip together (from our accommodations to the smallest daily details) the 'deal' seemed fair.

but this post is about what i found out about the 2017 KIA Forte fuel economy.

since i generally try to live the life of the lowest possible waste and maximum efficiency, what we spent on petroleum considering the distance was nothing short of amazing.

i am a meticulous record keeper...here are the dry numbers: we drove 1348 miles and put in 30 gallons. Comes to 45 mpg average. Some days, the car trip computer would show 53-55 mpg for a 150+ miles day...i frankly though the computer was liying. the driving was mostly on empty mountain roads and highways, but also included un-paved, cross-country approaches to some parks and peaks and about 10% city driving. in one word, it was NOT all ideal steady highway.

impressed, i made an inquiry into the car specs...it is rated for 28 city and 38 highway at best. the engine is a 2 L, 4-cyclinder 147 hp. plenty of umf imo...

the question that bugged me - how come it did so much better than the specs? was it the driving style ? the relatively slow speeds (about 50 mph average), the altitude above 5000 ft ?

me thinks it is a combination. indeed her driving is as economical as it is graceful... driving the car at lower speeds and the 'eco' setting (economy) must have contributed too. the altitude contribution is where it gets ambiguous. some studies found a modest efficiency increase, others - none or a decrease..

whatever. i wonder if anyone came across a similar effect on economy driving at altitude ?
DJPbaltimore:'John Kerry is an honorable person and would not call out the Russians if there was not evidence', 'the 2 of you are russia stooges'
in foreign policy there are no eternal friendships or eternal enemies, only eternal interests
User avatar python
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15 Aug 2017 14:45

I have a Yamaha Super Tenere.(1200cc) your car gets much better gas mileage than my bike.!!!.my Toyota is also a guzzler..
Unchained
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15 Aug 2017 14:55

I don't own a car, but rent one whenever I need it. Every summer I drive up to Oregon (from the Bay Area) to go fishing and camping (and this year, I'll also be looking at the eclipse). I rent the smallest and cheapest--and hence, generally most fuel-efficient--car available, but often, like you, still find the mileage better than expected. I keep records, and while I'm not going to dig them out now, I believe one year I got close to 50 mpg on the highway. Typical is around 35-40, > 40 is not uncommon. Moreover, it could probably be more. I've read that maximum fuel efficiency occurs at around 50-55 mph (so, yes, if you drove at around 50 mph, you should be getting maximum mpg). I avoid driving as fast as I could for just this reason, but I do drive faster than 55 on the way up.

Equally impressive, I have a folding canoe/kayak that goes in the car on the drive up, but when I get up there, to save time assembling and disassembling, I put it on top of the car. You can appreciate that this will greatly increase wind resistance. Moreover, because it's so light, it shifts easily, and I generally drive very slowly when it's on the car--like 20-30 mph. Plus at that point I'm driving on relatively narrow and winding roads, sometimes with broken pavement, where one has to go more slowly, anyway. A lot of factors that should hurt fuel efficiency. I still get 30+ mpg under these conditions.

Finally, I should mention that I'm well above sea level where I fish, so possibly that has an effect, too.
Merckx index
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15 Aug 2017 15:26

I have gotten slightly better fuel efficiency at higher altitudes with both two and four wheels.

That's odd (but good) that the Kia got seven mpg better than the EPA rating. You should contact Kia, and have them give you a car to test. :)

To stretch your topic a bit, what happened to the little economy cars that got 50-60 mpg?! Nearly every manufacturer used to have an inexpensive car that got 50+ mpg. Most manufacturers have hybrid cars that get around 50 mpg combined, but they are $30,000 ish. The Toyo Prius C is $21,000. The Hyundai Ioniq has the best EPA rating at 57/59 mpg for around $24,000.

Chevy's tiny gas car (I forgot the name) only gets mid 34 ish combined mpg. Kia has several less expensive little gas cars with combined mpg just above 30. My wife's three previous cars were a VW Rabbit ($6,000 used), Geo metro ($8,000 new), Honda Insight ($12,000 slightly used), and all three averaged over 50 mpg combined. Note: she now has a Mini Clubman...don't get me started.

I have read that some of the issue is that cars weigh more now because of emissions and safety equipment, and that is the reason that they are less fuel efficient. 20 mpg less efficient?!

I got on this rant because my Toyota Tacoma is getting long in the tooth, and I only need a pick up maybe five times per year so I am debating replacing it with something smaller, more fuel efficient, and more fun to drive.

I commute on a motorcycle (Ninja 650 now, but its on craigslist) and get 50 ish. which is horrible! It should get 100+ mpg even when my wrist is bending, but the moto is about fun.
jmdirt
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15 Aug 2017 15:43

Have a Toyota Tercel..not sure the year but mid90(95?) Gets in the 30s..also have a new Chevy Trax bought against my wishes gets high 30s both auto transmission .. I ride the bike daily and it has a fuel economy calculation number on the speedometer..at @70-75 get above 43mpg.. but San Diego traffic doesn't travel anywhere near and w the RPMs below 4500 my motorcycle mileage number goes down to 33-38mpg.. when it rains and I drive a car I enjoy the extra cups of coffee and eating while driving but the waiting in traffic just F-in sucks.. I split lanes at very low speed..to make some progress but mostly just to avoid pulling in the clutch 1 million times.. I will have a bike rack for the motorcycle soon and my miles per gallon is going to suffer..
Unchained
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15 Aug 2017 16:08

I've had to use an online converter to get an idea of the fuel efficiency, but I have to say 50 mpg seems quite standard here. I have owned 3 'tourer/break/station wagon' cars the past 6 years, and they all had >50 mpg. The trick to fuel efficient driving is pretending you have bad breaks - keep your distance and drive a constant speed. The NOx with diesel cars is a problem though.

Of course, our fuel is 3x more expensive than yours, so that may encourage manufacturers and buyers both into getting more miles more gallon. That's also apparent from the fact that the same model in the US version has much more hp than the European version. I guess Americans are used to it, but it's not really needed. Here, taxes are higher if you have more hp.

This is my current car - highly recommended:
Image

jmdirt wrote:Note: she now has a Mini Clubman...don't get me started.

Auch. Many condolences.
User avatar Jagartrott
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Re:

15 Aug 2017 20:25

Merckx index wrote:I don't own a car, but rent one whenever I need it. Every summer I drive up to Oregon (from the Bay Area) to go fishing and camping (and this year, I'll also be looking at the eclipse). I rent the smallest and cheapest--and hence, generally most fuel-efficient--car available, but often, like you, still find the mileage better than expected. I keep records, and while I'm not going to dig them out now, I believe one year I got close to 50 mpg on the highway. Typical is around 35-40, > 40 is not uncommon. Moreover, it could probably be more. I've read that maximum fuel efficiency occurs at around 50-55 mph (so, yes, if you drove at around 50 mph, you should be getting maximum mpg). I avoid driving as fast as I could for just this reason, but I do drive faster than 55 on the way up.

Equally impressive, I have a folding canoe/kayak that goes in the car on the drive up, but when I get up there, to save time assembling and disassembling, I put it on top of the car. You can appreciate that this will greatly increase wind resistance. Moreover, because it's so light, it shifts easily, and I generally drive very slowly when it's on the car--like 20-30 mph. Plus at that point I'm driving on relatively narrow and winding roads, sometimes with broken pavement, where one has to go more slowly, anyway. A lot of factors that should hurt fuel efficiency. I still get 30+ mpg under these conditions.

Finally, I should mention that I'm well above sea level where I fish, so possibly that has an effect, too.

I remember you typing that before, and I'm envious! So much money saved: The obvious up front saving of $20,000+, plus no $ spent on: insurance, fuel, tires, oil, brakes, filter, wipers, bulbs... I would like be go without a car, but unfortunately my job is 20 miles away. The commute is just not safe by bike, plus there is no facility to shower. Its only slightly safer on my moto. When I retire I will definitively do what you do, and just rent when I need to go out of town.
jmdirt
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Re:

15 Aug 2017 20:58

Merckx index wrote: Every summer I drive up to Oregon (from the Bay Area) to go fishing and camping (and this year, I'll also be looking at the eclipse).
Sorry for somewhat derailing this thread, but where are you staying at in Oregon for the eclipse? And, more importantly, do you have your eclipse-approved glasses already? (They've been selling like hotcakes here, have an extra legitimate pair if you need it.)

Ok, back on point - I drive a '67 VW Bug, so really not much gas efficiency there. Unfortunately. But I drive as little as possible, so there's that.
User avatar Tricycle Rider
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Re: Re:

16 Aug 2017 01:59

jmdirt wrote:I remember you typing that before, and I'm envious! So much money saved: The obvious up front saving of $20,000+, plus no $ spent on: insurance, fuel, tires, oil, brakes, filter, wipers, bulbs... I would like be go without a car, but unfortunately my job is 20 miles away. The commute is just not safe by bike, plus there is no facility to shower. Its only slightly safer on my moto. When I retire I will definitively do what you do, and just rent when I need to go out of town.


Yeah, I wouldn't do it any other way. I occasionally need a car to get something from Home Depot that I can't carry on a bike (and what I have carried on a bike you wouldn't believe), and used to rent a car for that, but then discovered a taxi was cheaper. Basically, I use a car so infrequently that it would be a waste just sitting in the garage all that time.

Tricycle Rider wrote:Sorry for somewhat derailing this thread, but where are you staying at in Oregon for the eclipse? And, more importantly, do you have your eclipse-approved glasses already? (They've been selling like hotcakes here, have an extra legitimate pair if you need it.)


I fish mostly in the Cascades, south of Bend, and Sunday--hope there won't be too much traffic?--I plan to drive the hundred or so miles north into the total zone, I'm thinking Prineville. Anywhere it's not too crowded. When it's over, I'll head back to my campgound.

My younger brother is an amateur (in the strict sense, basically a pro) astronomer. He and his wife have seen every eclipse for the past I don't know how many decades, traveling all over the world to get to the viewing places. As it happens, he now lives in Oregon, so won't have to go far this time. I got worried that maybe eclipse glasses would be sold out, so he's sending me a pair.

Ok, back on point - I drive a '67 VW Bug, so really not much gas efficiency there. Unfortunately. But I drive as little as possible, so there's that.


In their time, they were leaders in fuel efficiency, as I recall. But if you have a 67 VW bug, you could probably sell it for enough to buy something a lot newer. I think those old cars are worth a lot.
Merckx index
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16 Aug 2017 09:33

appreciate the feedback from everyone...

it appears that a consistently high altitude DID help the engine economy on our trip.

the effect on available power must be the opposite due to reduced oxygen. no ? hence having 150 horses was a precondition to achieving the economy AND yet a comfortable, safe ride on highways. i mean, a driver with a 'heavy leg' driving some puny (say 90 hp) box at 65 mph up the hills we did, would LIKELY over stress the engine and likely NOT achieve the economy we did ?

I am thinking aloud, b/c we now seriously consider buying a car again. as everyone can guess by now, the fuel economy tops the list. in manhattan, we cant afford having 2 cars. meaning, as much as i liked kia forte, unfortunately it cant be the LONG TERM choice, b/c it's too small physically for me.

a hybrid appears the only choice...prius looks attractive. curiously, I got a ride in a prius during the aforementioned trip and while i fit snugly, but all right with a few seat adjustments... a new mexico family we visited owns 2 priuses - a 2001 and 2004 models. both were bought new and still run fine. i got a ride in the 2001 model to the Hermit's peak we hiked a week ago. i was impressed. the trip computer of this dinosaur was showing consistently over 50 mpg with (very curiously) our ride up being more economical (?) than our ride down. according to the owners manual it ran on nickel-metal hydride batteries and only 20 Kwatt engine. its petrolium engine horse power i cant recall, but it was not much bigger...

the purely electrics aren't there yet from a practical standpoint. but the the hybrid technology must have improved since the dinosaur i rode in...
DJPbaltimore:'John Kerry is an honorable person and would not call out the Russians if there was not evidence', 'the 2 of you are russia stooges'
in foreign policy there are no eternal friendships or eternal enemies, only eternal interests
User avatar python
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Re: cars and fuel efficiency

16 Aug 2017 10:15

....ok....this is a discussion about fuel economy right ?....and the fact it was surprisingly high....

...and most of the driving was at altitude ?.....because if it was that by itself may explain things....as time trialers know you hit an aerodynamic brick wall at around 27mph and there after a huge amount of effort is dedicated just to overcome air resistance ( which is logarithmic...read huge increases as speed increases.. )....its something like 90% of the effort over 28mph and then goes north ( if memory serves me well ).....Eddie did his hour record in Mexico City for a reason eh ....

....so could thinner air and resulting lower air resistance be the answer ?.....so its not just car efficiency but its more correctly the efficiency of the car in thin air....cause the increase in fuel efficiency was quite large ( even taking into account the extra weight of a very full car ) so a huge change had occur in the function and air resistance at speed is huge....

...sorry if this was referred to already....

Cheers
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Re: cars and fuel efficiency

16 Aug 2017 10:37

I've got no car, not even a driving licence and am proud of it, got no problem with it. I don't want to pay for a driving licence in order to pay for a car, to pay for the insurance and to pay for oil. People with no car will get rich. That way I cannot be held responsible for climate change either and anyway with the soon to come energy crisis, the most likely is that there will be no more cars within a dozen years anyway.
Echoes
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Re:

16 Aug 2017 11:18

Merckx index wrote:I don't own a car, but rent one whenever I need it.

Several of my colleagues use a car-sharing service (and rent a car for holidays).
Only makes sense if you live in a densely populated area though, as the pick-up locations are sparse outside the cities.

blutto wrote:....so could thinner air and resulting lower air resistance be the answer ?

I think at altitude there's a combination of increased efficiency due to lower air resistance and reduced efficiency due to lower oxygen levels. Probably the end-result (better or worse efficiency) will depend on many things (driver's style, engine size, fuel type, etc.).
User avatar Jagartrott
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Re: Re:

16 Aug 2017 14:19

When Python mentioned altitude, I assumed he was talking about air resistance. Of course if there is increased efficiency at altitude, that’s where it will come from. That’s why I mentioned driving with a boat on top of the car, because that definitely has an effect on air resistance and thus efficiency. For the same reason, you’ll see less mileage when driving into (or crosswise to) a wind. This should all be obvious to cyclists (though there is no wall at any specific speed, because the relationship of speed to air resistance is a continuous mathematical function).

There may be an effect of reduced oxygen concentration on the engine itself, but I'm not sure how that works. There will be less gas injected to maintain the fuel/oxygen ratio, but that means both less power and less gas use. I would think there would be no net effect, except in the long run there will be more wear and tear on the engine, because more cycles have to occur for a given power output. Maybe ScienceisCool will weigh in on this.

Air resistance is also a major part of the reason why efficiency maxes out around 50-55 mph (though I believe it can be higher for some models). The faster you drive, the more energy has to be used to overcome air resistance. It’s more complicated than that, because engines are designed to operate optimally at certain speeds, but efficiency will always decrease at some speed because of the air resistance.

Jagartrott wrote:Several of my colleagues use a car-sharing service (and rent a car for holidays).
Only makes sense if you live in a densely populated area though, as the pick-up locations are sparse outside the cities.


Yes, and here in the Bay Area, we have not only those, but also bike-sharing services. I was surprised to see a couple of places where bikes are available not that far from where I live.
Merckx index
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17 Aug 2017 12:32

Moving from the west coat (Oregon) to east (CT), was rough for me because of the lack of bike lanes, and presumption on the east coast by most people that driving is the way to get almost everywhere, and cycling is a type of recreation. So I'm stuck commuting every day by car - the only way to ride to work would be death defying, and many weekends take my bike (road or MTB) in the car to get somewhere nice to ride.

Having said that, I live in a small town, and can often head out my door and ride for 2 hours over rural roads without taking my foot out of the pedals once.

I currently own an old Subaru Forester, with over 200k miles. It has served me well, but is nearing it's end of life. My next vehicle will likely be a used Prius, or Honda Civic hybrid, simply because of the fuel efficiency, plus reliability. I don't own a house with a garage, or I'd consider something like a used Nissan Leaf.

If you're curious, I buy used because I refuse to go into debt for almost anything, and am a big believer in socking as much money away for retirement as possible, and any splurging of money breaking this rule should be cycling related. :)
User avatar Alpe d'Huez
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17 Aug 2017 12:46

I also buy second hand. Much more efficient.
I bought that Mazda 9 months ago when it was not even 2 years old and 22.000 km for 60% of the 'new' price. Crazy.
User avatar Jagartrott
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03 Sep 2017 22:35

Several mentioned hybrids so I've been keeping my eyes peeled for an article that I read several years ago, but haven't stumbled across it again yet. My poor summary of it is: if your main reason for buying a hybrid is to save money, do the math first because they may not save you enough to recoup the additional price. If you spend $10K more, you have to save a lot of fuel money to get that back. The '02 Honda Insight that we got with only 12,000 miles on it was priced the same as the gas only cars in that "class" so we came out great in the 13 years that we owned it. Also, cars like the Prius obviously do well, but some hybrids don't get that much better fuel mileage than their gas only competition.
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