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Going for the best MPG up a hill

  #1  
Old 03-30-2004, 02:13 AM
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Hi

Now that warmer weather is finally here in Atlanta (sometimes 80's) and my HCH CVT is more broke in now (6KM) I was a little puzzled of why my MPG is not getting significantly better. The first week of March the temps were still 60-70 and that's when I got my current MPG record of 62.2 over about 44 miles.
My tank averages have only gained a couple of MPG's.
I guess that I should expect better averages but I'm not sure.

I've just surfed around and found a VERY informative posts in
"Hey xcel"
This is great stuff we can use.

After reading xcel's expanation of driving with load I realized I've slipped my technique to driving to a combo of MPH and MPG with MPH being more important.
I'm sure this is where I've gone astray and can't wait to try it out again.

May I ask how one would handle a 1 mile long slow incline? I have quite a few of these, speed limit is 45 and zero traffic at 3:00AM.

Also the same question on one big hill that always kills 2.5MPG by the time I reach the top. There's no practical way to go around and I always HATE it every night!
It's freeway and speed limit is 65 and the hill is about 2.5 miles long. I know where the flatter areas are and always feather back when I can but the FCD is almost always locked in below 40 to get some assist. The hill is shaped like a big check mark beginning with a big decline. The only glimmer of hope is that I take the hill at 2:30AM, and 18 wheelers are there going slower as well. I don't draft trucks but am happy to follow at a safe distances.
Bottom of the "check" is a known speed trap.

Any ideas?
I know some Hybrid drivers here that have more experience on hills, mountains, etc may hopefully have some input.

Thank you in advance,
Steve & family
:unsure:
 
  #2  
Old 03-30-2004, 03:23 PM
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yah...the interstates in georgia can be quite steep, even changing to quarter throttle i'll commonly loose 10 mph...i really dont think there is a way around it.
 
  #3  
Old 03-30-2004, 04:31 PM
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If I'm not mistaken, you'll be having a gain in mileage on the way down that hill, never needing to press the accelerator, no? In the Prius, I'd cancel all energy flow and would be accelerating down the hill, or if it was steep enough I'd just cruise and charge up the battery.
 
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Old 03-30-2004, 05:50 PM
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Often times there is a decline on the other side, sometimes there's not.
Guess I'll just have to pull the hills, squint & bear it.

BTW
Tried xcel's tips.
Last night had great results, back up to 58 point something MPG in a pouring rainstorm.
This afternoon I broke my all time record and achieved 63.4 MPG over 45 miles.
This was with a strong head/cross wind as another storm is coming in!

I guess I really shouldn't complain about hills and such but each drive is a new challenge. Gotta try for better next time!

Steve & family
 
  #5  
Old 03-31-2004, 03:23 AM
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Floor it, and pass the slow people. Constant speed is the key for the best MPG's in my car.
 
  #6  
Old 03-31-2004, 09:46 PM
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Hi Hot_Georgia_2004:

___It is a bit late so I have to get to bed Ö I hope the following makes sense even if I am not finished with it just yet?

___The law of diminishing returns as far as higher temperatures are concerned might be at work here Ö

___I have a theory but I am just guesstimating at this point in time until I get a scan-tool connected and watch the AITís and coolant temps over a few thousand miles as the spring and summer progress.

___A friend of the family and a good friend at work are into the drag racing scene pretty heavily Ö One races under his racing companies logo (Pit Palís) while the other helps build drag engines and is an EMT (Emergency Medical Technician) at the 2 main Drag events each year. From what they tell me, the Chicago Route 66 Racewayís drag strip is one of the fastest in the country at the 2 specific times of the year. When temperatures are in the mid to high 60ís or low 70ís in the spring and again in the late Fall events, some of the fastest times recorded are achieved at the NHRAís Drag Nationalís at this particular track during this particular period of time. It is not only one of the best tracks ever built for an event such as this but itís these slightly cooler temperatures and medium reading relative humidity that offers both an outrageous amount of traction and huge amounts of HP (Cold Air Intake type increases in HP). I know for a fact that Cold Air Intakes are exactly the wrong thing to do for maximizing mileage during the winter months as explained in previous posts. With that out of the way, there comes a time that HP from a CAI (Cold Air Intake) and Fuel Efficiency from a WAI (Warm Air Intake) are near matches or cross one another if they could be graphed. When and where this happens is still up to conjecture but I suspect that somewhere in the mid 70ís - 80 degrees F as measured from the AIT sensor (Air Intake Temperature as measured by an OBD-II scan tool somewhere in the intake plenum) is where this crossing of the 2 may happen. At that point or very near it, I can bet you will receive a maximum fuel efficiency when considering ambient temperature as the only variable in the equation. Chisight (a fellow Insighter near me) has done some extensive data logging through this time and temperature period and I believe he has mentioned that any WAI should be removed as AITís hit the 80 + degree mark. That would leave those of us that use WAIís and Radiator blocks achieving maximum mileage with winter time high oxygenate/lower BTU based fuel in the low 60ís to maybe 70 degrees (degrees F ambient temperatures). Rick Reese runs his WAI year round and I might just do so myself but I will always keep Chisightís data logging experience in the back of my mind given I lose the use of the resonator in the Insight when the WAI is plumbed and that resonator is supposed to help with the fuel/air mixtures internal to the intake in some form whatever that may be?

___If this theory is in fact true, the maximum mileage one may achieve in a Honda ICE equipped Hybrid or otherwise would be achieved when you have an AIT of ~ 80 degrees. And that corresponds to 70 -75 degrees F ambient in a std. automobile without a WAI mod(s) or maybe 60 - 70 degrees F with the mod(s) installed as mentioned directly above.

___As for Driving with load, I absolutely detest hills, foot hills, and mountains. I have seen the climb from behind the windscreen of the MDX from one end of Kansas to the other (E to W is ~ 3,000í Elevation climb) with miles of rolling hills in between taking there toll. Unfortunately, driving with load does have its limits. In the Insight, a 100 foot rise over Ĺ - 1 mile is enough to lose .3 - .5 mpg. If there is no traffic (I know that is almost impossible given Atlanta and where I drive here near Chicago), I can sometimes lose nothing but am traveling as little as 43 mph as I reach the apex Ö Not practical for most and can only be performed when there is absolutely no traffic for quite a distance behind me.

___I donít have time to proof read this much so I will probably add and edit a bit more later on Ö

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email protected]
 
  #7  
Old 03-31-2004, 10:56 PM
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That would explain , I suppose, why on some days when I can expect less than good results it ends up being a very good run:
And other times when I expect a great mileage day it ends up much less.
I had assumed it was because of a combo of ouside temp, humidity and mabe even
atmospheric air pressure.
Some days it just doesn't seem to want to burn as good!

I'm definetly at an advantage with the timing of my commute at 2-3AM.
With no body behind me I'll let it slow down on the freeway hills to about 48MPH and hold it there @ max FCD as possible without slowing any further. If traffic is approaching I'll very gradually increase speed to 55 over about 60 seconds and let the passing +60MPH traffic blow by then if it is clear again, I begin to raise my FCD as much as possible.

Once I clear those big hills I'm in heaven.
I could stay on the freeway but the limit goes up to 70MPH and the hills continue.
I exit the freeway before that and finish the last 19 miles on a parallel highway.
The highway is a little twisty and I drive an extra 1.2 miles but it usually has zero traffic and I can keep the FCD on 80-120 much of the way.
Average speed is about 42. Occasionaly dips to 35 to keep the FCD up.

I guess there really isnt any great way to deal with the hills.
Steve
 
  #8  
Old 04-01-2004, 09:54 AM
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Hot_Georgia_2004
Before you owned an Insight, did you ever think there would be a time when spending more time on the road would actually be enjoyable? As long as I'm getting better gas mileage, I don't mind the extra minutes of time on the road. Sure I'm not passing cars much anyomore, but the benefits of the higher mpg is a very rewarding payoff.

Hills-
Besides the usual rolling hills in Wisconsin, I have a large 3 mile up and down hill to tackle every day. (One of these days I'll measure the grade.) Most times I take the approach of going a little faster heading into into the ascent and then slowing down to no lower than 55. Sometimes I'm lucky and a cement or dumptruck which allow me to go slower near the apex. If I slow down too much, I do need to downshift. Usually I can make much of the lost mpg on the downside of the hill, but not always. I especially cannot make it up if, upon approach, I had a very high mpg on the screen.

Currently the road is two lane, but soon it will be a four lane divided highway. When it changes, it will allow me to slow down more, if necessary, without impeding traffic.
 
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Old 04-01-2004, 01:16 PM
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Thanks Eric.
I have a new 04 HCH CVT. (Not the Insight)

It replaced a 1994 Dodge Spirit 4cyl with 160K miles that got max 23MPG.
The car was wrecked and repaired twice, the repaint was old and peeling off,
inside was dirty, stalled out, loud exhaust etc etc. You get the picture.

90% of the time I drove it 80-85MPG in the Left lane trying to get past the car ahead. Generally got 16-18MPG. Tried to slow down to curve my gasoline bill but that only lasted a couple of weeks. It was just too boring.

I knew I'd have to replace my old car soon and wanted to help my gasoline bill.
The replacement had to be really extra nice, not a cheap Focus, Echo etc.
Being a husband and father of 3 small kids and my past driving habbits I knew if I got a regular ICE car that soon I'd be back in the old habbits.

It's not very smart to be swerving traffic, pushing the car ahead of you and going 85 MPH in a subcompact. (Or really any vehicle)
I wanted to change how I drive, have fun at it in a car that is designed specifically for outstanding MPG.

The paticular hills I mentioned are 4 lanes wide and currently in a construction zone with posted limit of 55 so I let it drift down lower.

The top is an almost flat incline, then is a good mile downhill run to another 2 mile flat incline, then a more severe hill that's a mile long. Right after that I exit and can take a parallel highway.
The highway home is about 19 miles long and is generally downhill and can maintain 82 on the FCD much of the way. Zero traffic.
Last night I REALLY worked at it and somehow I only lost .8 MPG by the time I reached the exit so I guess I'm doing OK. Perhaps tonight I can do .5 !

My commute in my old car CC locked in at 85 straight freeway took 50 minutes.
I could lock CC in at the speed limits and make it home in an hour.
My current drive takes me home in about 1hr 15 minutes.

I don't mind the extra few minutes cuz I truly enjoy playing this mileage game.
I don't usually even have the radio on so I can get a better sence of what the car is doing.
Driving my old style was really very intense wondering if I'll get a ticket, smack a deer, frantically trying to find away around the "JERK" in front of me etc etc.

My drive now is also intense but not in the same way as before.
With so many variables, adjustments to make, gauges to monitor and the ever present wack-ohs who drive 85 MPG (Hey wait a minute!) there is plenty to do.

Sounds like alot of work to some who are reading this.
Perhaps so but but it's alot of fun and with the good work gets GREAT results.
Call it a hobby or a sport, no one can deny that more than 700 miles on a tankful of 13 gallons of gas is more than AWESOME!

I knew that I was willing to give up my old habbits but needed more than just slower speed to occupy my time.

Eric, I'm sure you know what I mean. B)
Thanks
Steve
 
  #10  
Old 04-25-2004, 05:47 PM
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In my Civic CX (non-hybrid) I try to keep the engine in its more efficient power output band (70% to 80% throttle, RPM's below 3000, and accept whatever legal speed below 65MPH that power output will give me. I try not to ever floor the throttle during a hill climb (or during accelleration) since this causes the engine controller to adjust the fuel/air mixture to full rich to try to extract every last possible erg of enegy from the engine. Traffic permitting, as I approach the crest of the hill, I will release the throttle, push in the clutch and let the speed drop to 1/2 to 2/3 my original speed as I pass over the crest of the hill and then take the gravity ride down the other side.
 

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