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06-01-2007, 09:37 AM
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#11
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Registered Member
Join Date: May 2007
Posts: 23
Country: United States
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Thought I'd chime in here since I have a '96 Grand Caravan 3.3L.
You'll have fun with your scanguage. Experiment, experiment, experiment.
At 55mph on my van there was no MPG difference between vents and vents plus front windows wide open. Run the experiment on yours and you'll probably find you don't have to sweat it. A/C however was a killer, a little over 10% reduction.
And if you can stand going slower than 60mph you'll see big gains. Here's my data points when I was plotting my steady speed to instantaneous mpg. These values are uncalibrated (the tank average turned out 5% more optimistic than actual).
Code:
MPH MPG
35 30
45 34
50 31
55 29
60 27
The feedback is nice for determining whether re-routing is worth it. I have one route up and down a big hill that I rerouted to take 6% longer but I can get 35% better mileage.
We've moved up from 17.8mpg average to a little over 20 (lots of short trips, wife uses it for commuting and is slower putting these techniques to use)
As for tire pressure I have mine at 44psi (max sidewall) but can't say how much it helps. The ride doesn't feel harsh to me, though.
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06-01-2007, 10:45 AM
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#12
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Stay true to the Game!
Join Date: May 2007
Posts: 303
Country: United States
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savoF3 thanks for the responce. What's the best mileage you've received on your van? Hopefully my scan gauge will arrive today so I can start my experiment. My best has been 26 so far. Do you think that anymore is possible out of my machine? I pumped the tires to 40psi yesterday.
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06-01-2007, 11:34 AM
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#13
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Registered Member
Join Date: May 2007
Posts: 23
Country: United States
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Quote:
Originally Posted by popimp
savoF3 thanks for the responce. What's the best mileage you've received on your van? Hopefully my scan gauge will arrive today so I can start my experiment. My best has been 26 so far. Do you think that anymore is possible out of my machine? I pumped the tires to 40psi yesterday.
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I've only been working hard on improving since I found this site and cleanmpg.com, about three weeks, and I think I can wring a lot more out of it. I haven't had a real nice long trip where I can max it out.
I know a couple of years ago on a long hot interstate trip, 65mph, the best I got was 26.7.
Today I had a nice round trip down and up the steep hill here and managed 25.5 where I previously had a best of 18.8. A slightly longer route coasting down a nice straight grade rather than the steep twisties plus anticipating and coasting to lights paid off. Only cost me 6% further distance. And I suspect that it's actually more like 27.5 since (I think) the fuel should be completely cut coasting down that grade in gear and the Scanguage doesn't detect it (wouldn't give me above 80mpg).
I think the real gains are at the low end rather than at the "bests" though. That is, all those in-town trips where I'm eking out 20mpg ("old" EPA combined average for my year) instead of 17 are the real bread and butter. Hey, it's not a prius, but I'm moving 5+ people and that's 50cents a gallon savings.
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06-01-2007, 02:34 PM
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#14
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Registered Member
Join Date: Mar 2006
Posts: 675
Country: United States
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Ok, here are a couple of ideas and questions.
Since you guys have the scangauge, you could probably quantatively answer these a whole lot quicker than I can. Additionally, since I am not driving our van, it limits my opportunities.
First, grill block. I did my first test, using saran wrap across the front. I blocked probably 90% of the grill and bumper inlets.
Second, grill block. I removed the cover over the radiator and used a sheet of cardboard between the radiator and the a/c coils. I covered about 90%, changed it to 85%, estimated, due to temperature increases on hills, in warmer, 85ish weather.
Third, increase tire pressure. I am running 55 in my Civic wagon. On the van I have run as high as 50, but I backed it down because of the harsher ride.
savOF3; when you did the mileage profiling, did you run a test at 40mph. I was a little surprised to see as much of a drop in mileage, from 45 to 35, but I figure their is a break point, based on the engine, transmission and speed, I just would have thought it would be at a little lower rpm.
Anyway's, Great to have you aboard, good luck with your Scangauges.
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06-01-2007, 03:29 PM
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#15
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Registered Member
Join Date: Feb 2007
Posts: 722
Country: United States
Location: Connecticut
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Quote:
Originally Posted by popimp
... My question is, are these vehicles capable of getting better than 26 or am I fooling myself? Thanks for the help everyone.
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I can't say what mpg you'll be able to achieve - but I will say that buying another vehicle is going to have a significant dollar cost. I think it's pretty much guaranteed that you'll never get out of a dealership without buying a vehicle that's worth at least several thousand dollars more than what you're trading in.
That said, if your family can live with a vehicle that is going to get 30% or 50% better fuel economy then changing could be worth it. I'd base those judgements on the EPA numbers. Because, for sake of simplicity, assume that whatever you drive, if you're willing to work at it you can improve your results by some decent percentage. The amount that you can improve it isn't mostly dependent on the car, it's dependent on your own efforts. So compare the Caravan vs. other cars using raw EPA numbers. But watch out for the rating change between '07 and '08. They changed the rating system. You can see apples-to-apples EPA numbers at http://www.fueleconomy.gov/feg/bymod...emodelNF.shtml
I'll also toss in that aero improvements are a really good thing for any vehicle that's not very aerodynamic. I'm not sure what would be the best modifications for an '06 caravan but I'd consider underbody smoothing panels first: no concerns with outward appearance and car value regarding trade-in or car loan. Then maybe consider air dam improvements and side skirts / wheel skirts and maybe something for the back end.
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Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.
Now driving '97 Civic HX; tires ~ 50 psi. '89 Volvo 240 = semi-retired.
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06-01-2007, 03:29 PM
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#16
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Registered Member
Join Date: May 2007
Posts: 23
Country: United States
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Quote:
Originally Posted by Gary Palmer
savOF3; when you did the mileage profiling, did you run a test at 40mph. I was a little surprised to see as much of a drop in mileage, from 45 to 35, but I figure their is a break point, based on the engine, transmission and speed, I just would have thought it would be at a little lower rpm.
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No I didn't get a 40mph reading. I had to bump up the speed to not tick people off too badly.
On another 40mph road I usually see about 30mpg at 40mph, but since it's not the same road, grade etc I'm not certain about plotting it with the other data.
I believe but don't have a reference on me that the van should be in 4th gear and the torque converter should lock up at a steady 42mph. I haven't been subtle enough to find the exact point myself yet.
Also I moved up to 21.0 mpg on my worst trip, a 2mile round trip to my wife's work from a cold start with 4 stop signs. 26.5% better than typical runs before. The only reason she can't walk it is because she's heavily pregnant, but she's done working next week.
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06-01-2007, 03:32 PM
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#17
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*shrug*
Join Date: Sep 2005
Posts: 6,195
Country: United States
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Congratulations on the child!
Also, good job upping the mileage on the short run, that's a serious improvement!
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06-01-2007, 05:11 PM
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#18
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Stay true to the Game!
Join Date: May 2007
Posts: 303
Country: United States
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Brucepick and everyone else thanks once again for the help. I just moved here from Japan in March. I lived there for 5 years in the Air Force. While there I had 2 vehicles. A 1991 Honda Civic Hatchback with VTEC and a 1995 Toyota Corsa. Over there you can buy cars for really cheap. The reason I bought the Caravan when I moved to the states is because it was really difficult with 2 children, strollers, car seats, groceries, etc. With that being said I aslo got a really good price. $15,000 from our Base Exchange. The military has a program where you can buy new vehicles while being overseas. Even though mine is a 2006 I'm the 1st owner. Right now it has 1758 miles on it. I've been driving it since March 21.
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06-01-2007, 05:16 PM
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#19
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Stay true to the Game!
Join Date: May 2007
Posts: 303
Country: United States
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I got the scan gauge today! The only thing that I didn't like was the weak velcro glue. NO biggy! While idiling the van consumes .5gph. I've been able to coast and get 70mpg but most of the time it's around 45-50. Since I've only had it one day I really don't have alot of information other than that. Ohh I just filled up my tank today at Cheveron at my average was 15.07mpg. That sucks. My last fill up was 24.89mpg. Why such a big difference? My job is about 4 miles from where I live so it could possibly that my van isn't in closed loop long enough to get good mileage. I'll report back when I have more data. Thanks again everyone!
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06-01-2007, 05:22 PM
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#20
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*shrug*
Join Date: Sep 2005
Posts: 6,195
Country: United States
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Yeah, it could be the short commute, or perhaps a fill error. How large was the fill up?
Post your van in the gaslog!
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