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Discussion Starter #1
I decided to see if changing my driving habits could increase my fuel mileage. After driving a tank completely normally with no special effort to drive carefully or efficiently and on my normal routes, I calculated 19.49 MPG. This is all-city driving on busy streets so it's not very good; in fact it's even quite a bit worse than the 25MPG that the pamphlet says I should get. It's nowhere near the 40.8 MPG that others on this forum are commonly getting. Anyway, that was part one of the experiment. I know I was driving normally because I didn't even think about the experiment until after I had driven that tank.

For the next tank, I drastically changed my driving style, yet tried not to deviate from my normal routes and destinations. I coasted down every hill in neutral, I kept the revs low, I didn't blast off from stop lights, I didn't race anyone, I didn't use the A/C, I slowed down going up hills, I tried to time the lights better, etc. It seemed like I was driving very slowly everywhere and it was generally a pain in the ass. But, I thought, it should be worth it, because surely I'm going to increase my MPG and save some money. So then I filled up and did the calculation for the second tank: 19.31 MPG.

WTF?

All I can think of is that the pumps must have different stop times (I stopped on the first click) or maybe I just got into more bad traffic the second time. I don't think so, but obviously something went wrong, because it seemed to me I should have gotten much better MPG the second time.
 

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I noticed a more reserved driving habit worsened my mileage as well. Weird. I drove 70-80mph for 4 hours split over 2 different days, AC blasting, never coasted, had windows open sometimes, and for the rest of the time, drove between 60 and 65 with windows down and all that good stuff. Also some other mixed driving that I do every day. Normal things that would have you see mileage slip. I got 26.52 mpg on that tank. I didn't think it was good enough so for the next two tanks I coasted, used AC only if I was going 50 or more, windows down for less than 45mph which was usually just 25-35 mph, and never went over 55-60mph.. more 55 than 60 actually. I ended up getting 22.3 mpg on that first tank and 21.7 on the second. So screw driving like gas is $6976 a gallon.. I'll keep driving like its going out of style, instead. :lol:
 

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Baconpatroller said:
After driving a tank completely normally with no special effort to drive carefully or efficiently and on my normal routes, I calculated 19.49 MPG.
For the next tank, I drastically changed my driving style, yet tried not to deviate from my normal routes and destinations. second tank: 19.31 MPG.

WTF?
Hey Bacon. That's funny when I read posts getting 40MPG. Your second calc might be slight off due to error somewhere. But, I agree that with the change in driving habbit the milage would increase somewhat but not to 40MPG.

Cheers
 

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My old car (07 Yaris) was very efficient when ideling. Last winter, on the trans-canada highway, I waiting out a snowstorm and had the Yaris ideling for 2hrs and used up about 3L of gas. When I woke-up, all the other cars had about a foot of snow on them, while mine looked like it just had a car wash.

Yesturday, I had the Rav4 ideling for about 1/2 hr, cause I had the baby sleeping and it was an especially hot and humid day. I used up over 3L of gas in 30min. Strange, but the RAV4 engine uses up about 3 times more gas when ideling (compared to my old car).

Conclusion: RAV4 (4cyl) doesn't return good consumption when ideling. So, if it can't return good consumption from simply keeping the engine alive, it probably wont do much better from slowly ideling around town at 40km/hr.
 

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I drove from LA to Seattle. 25MPG constant, mostly driving 70-80MPH with AC on during the day. Back in Seattle going to work and back during rush hour, 24MPG.

And I don't even have 4WD nor V6... kinda dissappointed.
 

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My last tank was over 25 mpg, just driving around town (more "suburban" than "city" driving...).
 

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I have a Scangauge and have recorded fuel economy for every tank since new. I don't notice a huge difference between taking it really easy around town and driving normally. Either way I make mostly short trips with the same number of starts and stops. But then my normal driving doesn't involve much zooming around, racing people either.

I do notice a difference on a longer highway trip. Slowing down and going easy on the gas, compared to driving without thinking about economy, adds 3-4 mpg.
 

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I too did a similar test at the start of summer. I had decided to see what mpg improvments I could make by changing my driving habits, I too was dissapointed with the results at first. I decided to give a few more tanks of the conservitive way and my mpg's have gone from an average 18mpg's to ~21mpg's in all city driving. My usual route dosen't usually have alot of traffic but it does have alot of stop lights. I also made sure to use the same gas station as much as possiable to limit the variables.

My thought is to give it a few more tanks before you make any conclusions.

SS-
 

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Baconpatroller said:
For the next tank, I drastically changed my driving style, yet tried not to deviate from my normal routes and destinations. I coasted down every hill in neutral, I kept the revs low,
Coasting hills in neutral has negative impact on the fuel consumption. At least V6 has a very aggressive (in my opinion) fuel management and as a result at even the slightest downhill it cuts the injectors and the threshold for reconnect is very low (below 1000rpm). Going downhill in neutral prevents cutting the injectors and as a result instead of 0 gallons / hour it will use idle consumption which for the V6 is around 0.3 gal/hour. I would expect that I4 has a similar fuel management.
My consumption (V6) is ~19 mpg in the city and 27-30 on the highway depending on the terrain/number of persons in the car.
 

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Driving normally on my normal commuting route (like an idiot) I get around 20 mpg. If I actually try, I can get 24-25 mpg.

I accelerate briskly (higher load on the engine allows it to operate more efficiently) but then I immediately back off at the speed limit. Babying it up to speed and accelerating as slowly as possible is actually less efficient believe it or not. And you're just going to have to slow down again anyways, so any gas burned to go beyond the speed limit, especially repeatedly, is a complete waste of gas. On the highway I keep it to 55-65 rather than 75-80. Less drag = much better efficiency. I don't gun it out of corners if I'm just going to have to turn again or stop. Coast as much as possible. I'm not sure putting it in neutral to coast saves gas, and might actually burn more. Left in gear the drivetrain is driving the engine whereas if you put it in neutral now you need idle fuel which is wasted. Scangauge anybody? Look at fuel flow while coasting in gear vs coasting at idle. If I catch a light and know I'm going to be sitting at least 30 seconds, I put it in neutral and kill the engine. The gas you waste idling away at lights could easily be used to get you a mile or so down the road.

Getting higher efficiency out of your car requires you to identify where you're wasting the most fuel and adjust accordingly if you can. For people doing lots of highway driving, slow down. Higher drag at higher speeds means more waste fuel. For lots of city driving, the biggest issue is repeatedly accelerating a heavy car up to speed only to stop again, and then lots of idle time. If you know you're going to stop, only accelerate to 35 mph rather than 45 mph even if it pisses off the people behind you. And when you do come to a stop, kill the engine. Also for city driving, remove as much unneeded weight from the car as possible.

Bacon - you mention mostly city driving, but which phamplet is it that says you should be getting 25 mpg for city driving? You're confusing city and highway, and I don't believe the people for one second saying they're getting 40 mpg. Like I said above, coasting down hills in neutral might actually waste more gas. And going slowly up hills might waste gas too. I actually try to accelerate a bit and take advantage of gravity as much as I can before hitting a hill so that I have as much momentum as possible to carry me up the hill. The idea is to have enough speed to get over the hill in the highest gear possible so that the engine stays loaded in its most efficient state (heavier load at a very low RPM) rather than needing to downshift which puts it at a higher RPM where it's also less efficient. On local roads I try to hit the bottom of an uphill at just over 45 mph so that it'll get into 5th and then give it just enough throttle pressure so that it doesn't kick down to 4th.

Getting the best mileage on your specific routes and commute does involve a lot of experimentation and tests over multiple tanks of gas.
 

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SteVTEC said:
I'm not sure putting it in neutral to coast saves gas, and might actually burn more. Left in gear the drivetrain is driving the engine whereas if you put it in neutral now you need idle fuel which is wasted. Scangauge anybody? Look at fuel flow while coasting in gear vs coasting at idle.
cchrism said:
Coasting hills in neutral has negative impact on the fuel consumption. At least V6 has a very aggressive (in my opinion) fuel management and as a result at even the slightest downhill it cuts the injectors and the threshold for reconnect is very low (below 1000rpm). Going downhill in neutral prevents cutting the injectors and as a result instead of 0 gallons / hour it will use idle consumption which for the V6 is around 0.3 gal/hour. I would expect that I4 has a similar fuel management.
My consumption (V6) is ~19 mpg in the city and 27-30 on the highway depending on the terrain/number of persons in the car.
:thumbs_up:
 

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Driving down to LA in my normal driving mode I got 25 mpg in my Limited V6 with 3rd row, tow, and AWD. It is good enough for me. Last time I got close to 30 or something like that when I was driving really light and drafted behind trucks and cars.

BTW, I have over 20,000 miles on my less than 1 year old Rav4.
 

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I do much better

I have been able to get reasonable results for a V6
my daily commute is about 60kms with a 40% / 60% city/highway

I am averaging 10l/100 (23mpg) fairly easily. Last trip I went camping
up north 4 people gear and food cruising about 110. (mostly highway)
I was able to get 8.9l/100 (26mpg)

My goal now is to see if I can get to about 29mpg
 

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cchrism said:
Coasting hills in neutral has negative impact on the fuel consumption. At least V6 has a very aggressive (in my opinion) fuel management and as a result at even the slightest downhill it cuts the injectors and the threshold for reconnect is very low (below 1000rpm). Going downhill in neutral prevents cutting the injectors and as a result instead of 0 gallons / hour it will use idle consumption which for the V6 is around 0.3 gal/hour.
I did not know this. I am trying to understand how this would work. I mean the engine has to idle and fuel is delivered accordingly. These engines don't drop cylinders (aka cylinder deactivation) like some GMs and Mopar engines. So I would think that the lower and sooner one can get the RPMs down, the more fuel will be saved.

How does the engine managment system "cut the injectors" differently for low RPMs in gear and out of gear? :shrug:
 

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I'm not concerned with my Rav but I have tried driving like a grandma with a couple of my other cars and a couple motorcycles in the past. I've never even seen even a 2 mpg improvement.

I drive my '02 Civic to work. 60 miles round trip right through pittsburgh. The majority of my commute can be broken into about 30-40% at 80mph and 60-70% bumper to bumper traffic. I consistantly get 37-38 mpg and I usually accelerate aggressively. Changing my driving habits had minimal impact.

I have an 1800cc bike right now and I can not get any change in mileage no matter how I ride. If I ride like I normally do (very aggressive), I need to fill up about 5-10 miles before I do if I putz around like scooter.
 

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Discussion Starter #19
RAV4Don said:
cchrism said:
Coasting hills in neutral has negative impact on the fuel consumption. At least V6 has a very aggressive (in my opinion) fuel management and as a result at even the slightest downhill it cuts the injectors and the threshold for reconnect is very low (below 1000rpm). Going downhill in neutral prevents cutting the injectors and as a result instead of 0 gallons / hour it will use idle consumption which for the V6 is around 0.3 gal/hour.
I did not know this. I am trying to understand how this would work. I mean the engine has to idle and fuel is delivered accordingly. These engines don't drop cylinders (aka cylinder deactivation) like some GMs and Mopar engines. So I would think that the lower and sooner one can get the RPMs down, the more fuel will be saved.

How does the engine managment system "cut the injectors" differently for low RPMs in gear and out of gear? :shrug:
yeh, my assumption was that since putting it in neutral quickly reduces the RPMs below what it is when left in Drive, it was better to put it in neutral wherever possible. But if not, perhaps that might explain my anomalous result.
 

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Discussion Starter #20
Bacon - you mention mostly city driving, but which phamplet is it that says you should be getting 25 mpg for city driving? You're confusing city and highway
no, I'm not confused (I mean, about this, anyway), my pamphlet (I mean the 2008 Rav4 brochure) says the "fuel consumption rating" MPG for city driving is 25 MPG. It says I should be getting 37 MPG for highway. Seems crazy, doesn't it? But that's what it says.
 
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