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What is the best weather for Driving Efficiency

  • Hot and Humid

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  • Hot and Dry

    Votes: 0 0.0%
  • Moderate and Dry

    Votes: 0 0.0%
  • Rainy

    Votes: 0 0.0%
  • Cold

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Discussion Starter · #1 ·
Thought we could start a new thread on weather made for the Insight. In my experience the Insight is most efficient when driving in Hot and Humid weather. Perhaps it is because this air is less dense thus reducing drag or perhaps fuel combustion is just more efficient. I know cold air provides more power but the warm air seams to allow for better fuel/air mixtures thus getting more complete combustion and more time in lean burn). So if I were to rank weather for best driving efficiency it would look like this.

1. Hot and Humid
2. Hot and dry
3. Moderate and Dry
4. Rainy
5. Cold
6. Cold and Rainy
 

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nah... "hot" to me (and especially hot and humid!) means you gotta run the A/C. That puts a load on the engine. So I went with moderate and dry. I'd still put the rain (drag) and cold (no idle-stop, less lean-burn, plus it could be snow) at the bottom.
 

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Aaron Cake said:
As for the A/C, only whimps need air conditioning. :)
Yeah, but you can easily cook your batteries without it, at least in Arizona. Something you don't want to do. If you feel hot while in the car the batteries are likely a lot hotter and nickel metal hydrides do not like heat. Been there, tried that, had recalibrations every couple of days.
 

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Discussion Starter · #5 ·
Hot and Humid

OK, I admit if you use the A/C when it is hot then the mpg is going to be better for mild and dry. If you don't however look toward a higher mpg average.

In regards to air density humid air is lighter than dry air. If it wasn't mositure could never rise to form clouds. (H2O has a molecular weight of 18 versus say O2 with a weight of 32).

Have fun, Rick
 

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I live in South Florida, Air Conditioning isn't a nice thing to have down here, it's a necessity. My first vehicle, a 79 dodge prospector (just like the 80 Dodge Ram) didn't have A.C and boy did I feel it. Luckily it was white so it repelled heat some and since it was designed w/o A.C it was very "airy", it just didn't get AS hot in there as a newer car w/o it's A.C on. But it was still a real pain.

So I live in a hot and humid place. Does this affect mpg? Any specific suggestions for using this car in such conditions, I've seen tons of info on driving in the snow and snow tires and how to deal w/ the cold.

I figured the heat is bad for the batteries so I got the best tint I could find on the car and want to add another layer of tint later on to the back half, to protect the batteries as much as I can. How can you tell when the batteries need "recalibrating"
 

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interesting discussion

I voted for cold weather. I am not positive, but I guessed cold because I would predict that the advantages of cold, denser intake air would beat the advantages of having to drive through it. But, I could certainly be wrong, I don't know what the trade off is there.

In case anyone reading this thread isn't aware of the advantage of cold intake air, cold air is generally better because it is denser and therefore has a higher concentration of oxygen. More oxygen in the intake air will allow for more fuel to me mixed and burned.

Well, I guess now that I think of it, denser air means more fuel. And thats what we're wondering about, not power (which is what Im used to discussing). I guess it would be similar to some sort of forced induction, but who says that forced induction is any more efficient (refering to fuel conversion efficiency or sfc) than naturally aspirated.
 

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Now I have voted, but if it was there, I'd support Moderate and Humid... here in Orlando, A/C is also a necessity on some days, and I can concur with the South Floridian that it is a necessity even more down there (i'm from S.FL).

Moderate so that you can go no A/C, but be nice and warn for the engine.

Per your question about "recalibration".... it's not something you do, it does it automatically when it needs to... it's more commonly called a 'recal' on the boards. Nothing you worry about.

Tint is a good thing, but don't lay it so thick in the back taht, on our heavily slanted rear winshield, it begins to impede your vision. You'd be surprised what heat the battery pack can take, and even with just 30% tint, I have yet to have a heat related charge restriction since it was installed.
Example: Computers should be kept cool: true. Is the weather outside ever gonna be hot enough to fry the computer? not really, since chip surface temperatures get MUCH hotter than any weather outside... if the fans are going, it'll be fine, regardless if it's pushing 120 degree air.
 

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Experience tells me that I get much better gas mileage in summer than winter in Virginia, but that was without air conditioning. I've heard bad things about Florida heat, etc. so I'm suspecting that the Insight does best in moderately warm weather.

Cold temperatures slow down battery chemistry and the gas engine runs very inefficiently until it heats up, which takes longer when it is cold. Excessively hot temperatures cook the batteries, shortening their life and, trying to protect the batteries from this effect, the electronic controls turn off either charging or discharging the batteries once they overheat.

Rain kills gas mileage because of the increased rolling friction, pushing all that water out of the way on the road, plus the small, but persistent kenetic energy consumed overcoming the momentum of all those raindrops.

So, basically, I'd expect that the best weather for a person standing outside is the best weather for an Insight, cruising down the road. It can handle extremes, but the extreme becomes a burden.
 

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I find I do the best MPG in very hot and dry weather, if I don't use the A/C. We don't do humidity in the desert, so I can't compare to that. About A/C, My wife and I drove to the White Mountians this last week end. We started at Phoenix at 110+ degrees at 1000 ft. and drove to Alpine at 70 degrees at 8500 ft. The MPG at the start after 250 miles on the tank was 84. At Alpine the MPG was 73, we used A/C about half way. On the way down the mountian, the MPG got up to 75 untill we turned the A/C on, we got home with 850 miles on the tank and 72.6 MPG. Last year I did this same trip without A/C and on the way down the mountian I gained 8 MPG. The point is the A/C hurts the MPG more than the 7500 ft. drop helps the MPG.
I also think a cross wind hurts the MPG more than a head wind. I think it has to do with the fact you are turning into the wind to keep from blowing off the down wind side of the road.
 

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If you don't factor in A/C use, then the hotter the better. Almost all Fuel Injected cars have an intake air temperature sensor. The hotter the air going into the engine, the less dense it is and so the computer injects less fuel. Result, less power but better MPG. Less dense air will have less aero drag too.

Humidity does not make much of a difference, (FI computers don't have/use humidity sensors) except the low humidity may cause a little less aero drag (and less A/C use too.)

Another factor, not really weather related, is that you should get better MPG at higher altitudes than at sea level.
 

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mpg at high altitudes

Don't agree with your "better mileage at high altitudes." Maybe in theory but in reality it don't happen. Vehicles starve for air in the higher elevations which means more throttle has to be applied, which in turn means more load on the engine causing more gas to be consumed. The computer trys to keep the various components of the engine at the preset determination of the manufactures. Vehicles from the factory are "normally" calibrated for an elevation of sea level. I for one get a lot better mileage at sea level than I do in my normal driving at my 2,500 ft. elevation. .......Yes the turbo does help in higher elevation...........maybe not mileage but for power. :twisted:
 

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Discussion Starter · #13 ·
Agree with Willie on the altitude (I observe the same results although not as big of an elevation swing on my commute). Also increasing humidity would lower air density not raise it (H20 molecules are lighter than O2 or N2). I have a 00 insight and track every tank of gas. My best effeciency is in Aug which for the southeast tends to be hot and humid. Note I don't use the A/C. Have fun, Rick
 

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I would think the ECU would be able to use the various sensors, particularly the O2 sensor, to keep air/fuel mixture at the proper ratio regardless of altitude. Of course the air at altitude is less dense, so each cylinder of mixture would produce less power at altitude.

I don't know if it would hold for cars, given the addition of rolling resistance to pure aerodynamic resistance, but for light planes it's certainly true that you get better mileage and a higher cruising speed at altitude.
 

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I'm still getting horrible gas mileage and I live in hot and humid weather, ie. south Florida. My car's a CVT and it advertises 57mpg and looking through the forums a lot of people are getting higher than that. But ever since I've owned it I only average 44mpg maybe less. No matter how nice I drive. My car now has about 4500 miles on it so it should be broken in. With my last fill up things have gotten worst, I now show an average of 32mpg (i hit the trip reset button after filling up). I haven't been driving aggressive or anything, it just seems like my gas mileage got all screwed up. I'll have to check the pressure in my tires but how can a car that's supposed to get 57mpg go down to 32mpg, sigh. I'm going to bring it into the dealer soon and tell them to check it over with a fine tooth comb, somethings causing it to get bad gas mileage. I think this latest fill up and me getting 32mpg is just maybe a bad tank of gas or poor gas quality even though it was Mobil. I still don't like getting my norma 42-44mpg gas mileage. It seems the only time I do real good is on straight aways where I don't have to constantly accelerate but I thought this car was designed for stop and go traffic, but everytime I accelerate after a green light if I floor it I get like 15mpg and when I accelerate moderately I get like 25mpg and if I accelerate like a granny I get like 35mpg during the acceleration process.
 

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Hummm... Probably a dumb question, but do you see the assist kicking in when you accelerate?

No matter what you do, you are going to see lousy instantaneous mileage while you accelerate. The car has to expend X amount of energy to overcome the inertia of the car, and get it up to cruising speed. When you reach that speed (on level ground), the engine only has to put out enough power to overcome air and rolling resistance (plus AC and so on), so the instantaneous mileage should go up to the 50+ range.

Bottom line, if you are driving a lot in traffic/lights where you're constantly stopping & starting, you are going to get lousy mileage compared to driving at a steady speed for the same distance. But if the assist is working correctly, you will still be beating any other car driving the same route.

One thing that I find helpful (and did long before I bought the Insight) is to look ahead and try to time the traffic lights. Don't drive right up and brake at the last minute if it's red (the way I see a lot of people doing), just back off and sort of coast in. If you're lucky it will turn before you have to come to a stop, if not, you will have at least been in fuel cutoff mode for that stretch.
 

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Yes, the assist comes on when accelerating or stepping on the gas at anytime. However I do sometimes wonder if it should be helping out more than I see it helping out. I also notice that my battery charge is at full and has not dropped below full since I bought the car. It never drops to 3/4 or 1/2, the assist is never on long enough to drain the battery. It only comes on for short bursts, never more than a few seconds. It's tricky to get the car to go into auto-stop mode while decelerating and creeping up to a red light in hopes it goes green but I've done it before. I've tried very aggressive driving as well as very passive driving, I've tried so many tricks and I just can't ever break the 50mpg mark.

I'm thinking now's a fun time to test Shell's new advertisement, that their gas gets you better gas mileage. Our cars are dead accurate on mpg so we should definately see if Shell gets better mpg or they're just plain lying. However Shell's usually more expensive so you gotta figure what an extra 1 - 3 mpg will cost you by paying more for that gas.

I think I'm going to overinflate my tires just a little over factory spec, then fill up from empty with shell gasoline and drive for 2-3 weeks as nicely as I can. If I don't break the 50mpg mark by the end of that period, it goes to the dealer for a full analysis.
 

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People driving the CVT in mainly city driving have reported an average of 50 MPG according to the mileage database on this site. Out of 6 reporters, half got less than 50 mpg and half got more than 50 mpg. Some of them might have been driving a "city" drive like the one I drive, which is more of a low-speed cruise on back country roads than a congested city drive.

It's possible that the dealer won't be able to do anything for you.
 

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"I also notice that my battery charge is at full and has not dropped below full since I bought the car."

I think that may just be a consequence of living in Florida, which as I recall is awfully flat :) I only see the battery charge drop more than a bar or two when I'm climbing hills. Even full-throttle acceleration from a standing start to freeway speed hardly budges it.

I wasn't suggesting going into auto-stop when coasting up to a light. (It will only do that below 20 mph.) However, if you're at a higher speed but decelerating, the engine should go into fuel cutoff mode, where it's not burning anything, just braking from the engine/regen. You should see the instantaneous mpg bar go all the way to 150, and a few bars of charging. (If you give it just the tiniest bit of throttle, you can get no regen braking so zero charging, but still in fuel-cutoff with 150 mpg showing.) That's about your optimum coasting point, where you'll get highest mpg.

With my 5 spd, I find I have to at least be touching the brake, and have the clutch in, for autostop to activate. Above the max autostop speed, I think trying to coast in neutral is actually slightly less efficient than being in gear, since the engine has to use fuel to idle. Don't know how well this translates to a CVT though.
 

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weather driving

Do not use the std. recommended tire pressure. I always run 48 to 50 psi all the way around. If you run over a dime, you can tell if it is heads or tails. :twisted: Mileage will increase, tire wear will be the best.....Proven after 80,000 miles of extensive testing. The high pressure in the tires will also "cut through" the water on the roads during those rain squalls in fla. (been there, done that) 8)
 
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