To The Moon: Upping economy in a 2000 Dodge Caravan

[101Volts]

UPDATE, 30-August-2014 - I've decided to retire this van from fuel economy logs. I saw a fuel leak under the van. I will say that the highest I saw this go on a single tank was 28.54 and that was mostly on one trip, mostly HWY miles.

This thread is about modifying my Father's 3.0 Litre, 4 SPD Auto Transmission Dodge Caravan.

Current Deletions:

A/C Belt Removed
A/C Clutch Fuse
A/C Clutch Relay (From the fuse box)
Bug Deflector
Handles from backs of Driver and Passenger Seats
Roof Rack
Seats; Middle and Rear

(About 200 pounds removed between floor mats and seats)

Current mods:

Plastic Stretch Wrap on Hubcaps
ScanGauge II
Rear Side Skirts, Partial, Duck tape
Weather stripping in some gaps

General maintenance:

Air Filter Changed - 2013-May-7, 8, or 9
Fuel Injectors Cleaned - 2013-September-06 (This didn't seem to make much of an improvement compared to how it was)
Oil Change with 5w20 Full Synthetic Oil (2013-March-23; However, We added 10w40 non-synthetic in late August as we ran out of Full Synthetic)
Spark Plugs Changed - 2013-May-13

Things checked at fill-ups;

Fluids
Tire Pressure - 46 for Winter, A bit higher for warmer months (50, Maybe)

Other info:

14 Inch Tires

Things I'd like to do to the van:

A/C Clutch Removal (It's not hooked up anyway)
Seafoam + Oil Change (At the 135k Mark or later; As of this edit we just broke 132k on 2013-11-21)
"Street Sweeper" Aerodynamic Strips on Sides of Van
Windshield Wipers Deflector

Driving is shared in this vehicle; My Father and I both drive it.

Money saved target; $320 - At $203.5x so far

Austin

[brucepick]

I'd estimate that anything over 25 mpg in "moon" is a good accomplishment. Nice work on the mods done!

Um, have you adjusted the ScanGauge at fillup time to get its gallonsreadout to match the pump display?

[elhigh]

I had a '92 with the 2.6 and 3spd, it never did better than 27 on its very best day. That was a long trip on the Interstate with a brand-new cruise control.

Of course, it puked up its ECC on that trip, but that's beside the point.

Getting over 25 is really good. I'm fascinated to see if it keeps it up, especially if you go deeper into the tank.

[pete c]

Are you sure it's a 3 liter? I didn't think the mitsubishi 3 liter was available that late. I would think it was the 3.3?

[101Volts]

Yes, It's a 3-Litre (See link Fuel Economy of the 2000 Dodge Caravan/Grand Caravan 2WD) and the ScanGauge was adjusted at the last fill up (EDIT: But did I do it properly?) Almost 6 gallons have been used so far. The van tends to get better economy if at a lower elevation; We're located rather high. (EDIT: Is that true?)

Also, The rear passenger seats were removed and the AC belt isn't connected.

Edit: The engine says it's a Chrysler.

EDIT: I'm wondering if it's true that the van gets better economy at a lower elevation and it's not just the fact that it's on a 100+ mile trip.

[euromodder]

Big car, lots of place for stuff that you (really) don't (really) need ...
I take it you've already thrown all the excess weight out - along with the rear seats ?


I once rented a Grand Caravan / diesel version - thirsty b@$t@rd that was.
Thankfully, there were 6 of us to spread the fuel costs.

[Blue Angel]

Not sure how much of an air dam you can get away with in the snowy months, but that's another option. Filling up the (enormous) wheel well gaps couldn't hurt. Coroplast belly pans... lots of stuff can be done, it just depends how self concious you are.

[101Volts]

Yes, The rear passenger seats were removed. A few things are carried around in the car but it's far from being a tool shed or Hoardasaurous Mobile.

I don't expect to be going far out with mods to this vehicle now. If/when I get a Geo Metro, I can do much more than I'm doing with this van. Also, Not much city driving is done in this van due to our location.

(Edit, 2013-September-18: I don't think I'm about to buy a Metro.)

(Earlier Edit: The below parts I now take with a grain of salt due to the fact I did such little coasting and not much distance in the tests.)

I tried to A-B-A the tire pressure between 50 and 55 PSI to find the most fuel-efficient pressure and I somewhat flunked it. At first I was going to use 50 PSI (Roughly) As A runs and 55 PSI as a B run but I'll have to reverse them. A third A run hasn't been made. The pizza pans were on for all these tests which is partially why there isn't another proper run at 50 PSI; They take time to take off and on.

Averages and totals for "B" Runs, (Roughly 50 PSI) Counting going from home to the gas station:

35.95 MPG AVG
0.10 Gal
188 FWT Max
3.8 Miles
1754 RPM Max
42 MPH Max
24.5 MPH AVG
$0.40 Cost

Averages and totals for "A" Runs, (Roughly 55 PSI) Counting going to the gas station (Again)

32.03 MPG AVG
0.15 Gal
188 FWT Max
5 Miles
1898 RPM Max
42 MPH Max
21.6 MPH AVG
$0.69 Cost

I did drive more for the "A" Runs but I think these are still somewhat valid, Especially when comparing my first ride from home to the gas station compared to my second run which was fairly close:

First Drive, at 50 PSI:

40.5 MPG AVG
0.06 GAL
186 FWT Max
2.4 Miles
1754 RPM Max
42 MPH Max
26 MPH AVG
$0.23 Cost

Second Drive, at 55 PSI:

38.9 MPG AVG
0.06 Gal
184 FWT Max
2.4 Miles
1898 RPM Max
42 MPH Max
24 MPH AVG
$0.24 Cost

I didn't deflate the tires from 55 back to 50ish today.

Also, I must note that I use hills (Down Slopes) for acceleration when and where possible.

Austin

[wmjinman]

That's weird - - - I'm a bit surprised you seem to be getting better mileage at 50 than 55psi in the tires. I wouldn't have guessed that.

[MetroMPG]

Lose the bug deflector on the hood. Easy mod, and good for another 0.296 MPG, guaranteed!