Dodge Dakota Testing - Fuel Economy, Hypermiling, EcoModding News and Forum

MadisonMPG · 03-08-2010, 11:29 PM

This is a post that I am doing over at the DodgeDakota forum, I will post the results here and there... You guys will probably accept the results a lot better.

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I will spend a few bucks of my own money to figure out the gas mileage of the 4.7L engine.

Here is the list of test I will do to try to get an answer.
#'s in parenthesis are my guess for MPG boost/reduction.

1. clutch fan on vs off +(0-1.0mpg)
2. 55 vs 65 vs 75 mph (22mpg vs 19mpg vs 18mpg)
3. e10 vs 100% gas (???)
4. 35 PSI vs 44 PSI +(1-2mpg)
5. bed cover on vs off +(0-1mpg)

*I will accept other tests to do from you guys, if I have missed something.

Test truck will be a 2004 Dodge Dakota, 5 speed auto, 2wd.I will maintain 65mph over a 5 mile course. (unless speed is part of the test) And the engine will be fully warmed for each test.

Now here's where it gets tricky, I will be using the overhead computer. This is not 100% accurate, but it will give me the difference in mileage, or at worst, show what helps/hurts.

If you don't like the overhead computers accuracy, i'm sorry, but I trust it for these tests.

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Today, I ran the 3 speed tests today. All three went phenomenally.

65mph: A:23.7 B:23.3 Avg: 23.50
75mph: A:19.7 B:19.1 Avg: 19.40
55mph: A:28.6 B:27.5 Avg: 28.05

The 55mph had a little inconstancy because of a guy cutting me off on the B run. I didn't have time to redo it.

Test went as follows: Accelerate up to speed, set cruise at X speed, clear overhead computer, run till exit I was using to turn around one , record MPG (while still on cruise). The road was kind of hilly, but I ran A going west on the road, and B going east. Gasoline was Route 66's 100% gasoline 87 octane. Truck was loaded with 2 people, total weight 385, along with 50 pounds of cargo. Truck bed cover was on, clutch fan was off. Ambient air temperature was 56 degrees. The front tires had 35 PSI of air, filled before the drive.

* I think I have covered everything? Like I have said earlier in this thread, I am NOT saying that the overhead computer is 100% accurate for actual MPG. But, it does show a pretty noticeable difference at speed.

I am going on a 6 hour trip this weekend, I am going to run 65 the whole time and see if I get somewhere near what this test shows.

MadisonMPG · 03-09-2010, 12:53 PM

No comments?

I just realized how freaking high that 55 mileage is, seems almost too high. The road I took was 7.5 miles and had rolling hills. And I used the same course for all speeds. Is 28 too high?

busypaws · 03-09-2010, 11:17 PM

Your doing good. This site talks about A-B-A testing and your doing the right thing. When no-one comments I think they all agree with you and are waiting for the rest of the testing.

If I remember my physics - The aero load on an object goes up/down by the square of the velocity. So going from 65 mph to 55 mph is not 10/65 or 15% better -- It should be something like (4225 - 3025)/4025 = 30% improvement in mpg. There are other factors like tire friction, pumping losses, thermal losses, etc. But at high speeds the aerodynamic losses are the one that get you. Because it is not all areo you did not get a full 30% increase in mpg.
I'm looking forward to the clutch fan test. I have a 94 Toyota PU with a full time belt driven fan (no clutch). With your clutch on/off test I can get a reading on how much I might save if I convert to an electric cooling fan. Watch the temp, don't overheat the truck when doing the clutch off. Lots of us start doing grill blocks and air dams to seal up the engine compartment to help with faster warmups and better aero. We have to watch the temp to make sure we aren't overheating.

MadisonMPG · 03-10-2010, 12:11 AM

Thanks for the info. I won't be able to do anymore testing this week, i'm going on vacation and will probably start testing some time next week. The truck has an electric fan that cuts on at 212* to keep it from overheating.

I actually am going to do a grille block test too, I just haven't got around to making one.

miaclarkson · 09-01-2010, 10:40 PM

can anyone help me about the dodge ram?

miaclarkson · 09-01-2010, 10:41 PM

i am having a trouble regarding with the parts.

wkumtrider · 11-02-2010, 02:38 PM

I have a 2000 Dodge Dakota with a clutch fan. I've always wanted to remove it. I can feel the truck slow down when it kicks on. What is weird is that the fan seems to run continuously in the winter, but doesn't run much in the summer. Is there any way to keep the fan from engaging during the winter?

t vago · 11-02-2010, 10:36 PM

Quote:

Originally Posted by wkumtrider

I have a 2000 Dodge Dakota with a clutch fan. I've always wanted to remove it. I can feel the truck slow down when it kicks on. What is weird is that the fan seems to run continuously in the winter, but doesn't run much in the summer. Is there any way to keep the fan from engaging during the winter?

Take the clutch fan off, and keep it in a safe place. Your auxiliary electric fan ought to be able to do the job during wintertime. If needed, you can easily re-install the clutch fan, for hauling heavy things or for towing.