2012 Dodge Grand Caravan Pentastar
 

I guess this is a bit of an introduction,
I've built and tinkered with vehicles for 35 years, always wanting a bit more performance and more fuel mileage on all of them. I guess maybe my 1986 VW Jetta turbo diesel I left alone because I thought it was pretty near perfect in the fuel mileage department. I am in Canada so I think in the old Imperial gallons, so my MPG figure may sound high for Americans. I am trying to adjust to L/100kms that my Caravan is calibrated in.

I tried to to post a graph of my fuel mileage, but I need 5 posts, so excuse my repeated posts. I'll try to make them interesting reading...

My last new vehicle was a 1999 Caravan and I remember its fuel mileage was terrible (17mpg) on the first tanks and gradually improved over 20,000kms to as much as the occasional 35mpg tank on long flat slow runs. So, I realize I have to be patient and get some miles and a baseline on this new Caravan before I can really prove any mods.

I bought this van because I like to travel and need to haul motorcycles and snowmobiles in all seasons, and I need a vehicle I can camp in. I had a Ford Taurus Wagon and a Jeep Cherokee before this and while they would tow the trailer, they were too small to camp in really, except in an emergency.

I gotta say, this Pentastar engine is peppy. It will scream! 285hp and fly by wire.
It had 100kms on it when I bought it, so for the first 500km I drove it pretty much normally, avoiding cruise control, high speeds and steady speeds. I didn't idle at all, used moderate throttle until warmed up, and then used up to 3/4 throttle quite often once the engine was warmed up. I tried to keep the revs down but 3/4 throttle delivers 6000rpm shift points. I played with the fuel mileage display, using it and resetting it often on the first couple tanks to get a feel what mileage for various conditions is, so I don't have an indicated mileage for the first tanks for this reason.

So, first ten tanks of fuel, speed and indicated fuel mileage on the meter:

http://sphotos-h.ak.fbcdn.net/hphoto...27827166_n.jpg

Any suggestions on what I can do to improve on this besides keep breaking it in and slow down?

I'd look at pre-heating fluids (synthetic, after break-in complete). Same for keeping coolant temps high with radiator cover (winter front) adjustments.

On vehicles specified for work, I think the best plan (past establishing a "perfect" mechanical baseline) is in:

1] Reducing all miles via trip-planning (combining errands, best-order-routing, etc); and,

1] Driving the remaining miles as well as possible.


There is a good deal of depth in those two, I have found. But reducing warm-up time to a minimum is basic to success.

.

Have you browsed our lists of mods & driving tips?

65+ Efficiency Mods

100+ Hypermiling Tips

Three immediate steps, in order:

-There should be an "Econ" button down below the radio that lights up a green leaf when you press it. That changes the TCM- it locks up the torque converter sooner and shifts less, even skipping gears. Automatics are funny- if the driver is going to be an idiot, more gears give better mpg. If the driver is willing to take some personal responsibility for it and meet the car halfway, there's a button that will give you fewer gears... for better mpg.

-Pump up the tires. I went up from 35 to 39 psi without throwing the TPMS light. It's my wife's DD and she's not a hypermiler.

-Get an SG or UG. Having multiple mpg displays helps you know what you're actually doing- the longer view, short trip and current values all work together.

My 2011 does pretty well. I reset the mileage back in June and it shows 20.3 mpg since then- which includes a few camping trips with the kids, the dog, a pop-up camper and a canoe.

1/2-3/4 throttle till somewhere between 2000-3000 rpm, let off to get it to shift, reapply as much as possible without causing a down shift and repeat till up to speed.

Good points. I notice the warm up mileage is terrible. My strategy has been to start and go immediately, use about 3/4 throttle to get up to speed briskly while driving heat load into the engine (to get it warmed up), then coast while at speed to maximize miles while minimizing enriched fuel use. This seems to work according to the on-board display, anyone have opinions on this strategy?

Winter is coming, I really like the idea of front covers. Van is designed to operate in Texas, doesn't need that air flow in Canada in January...

Will do fluids after break in, and I am a motorcycle rider so I minimize my cage (4wheeled vehicle) time on purpose all the time anyway. Bought the van at the end of July and it took a couple months to put 1000kms on it!

Yes, I have been a lurker for years actually, followed your projects, and successfully employed pulse and glide driving to get huge (30%) gains in mileage on a Taurus and Toyota Echo. Echo got 80mpg(imp) over a 1000km trip. Experimented with P&G with the Caravan and it will be a viable technique, including engine off P&G, which seems safe and easy with this vehicle. While P&G and EOP&G work, not always practical and looking for what others have found works with their Caravan. Notice on my graph slowing down directly corresponds with improved mileage!

I have to thank you for this site and I intend to be a financial supporter to return what you have given me here. Thanks!

Green Econ light ON! Done. I played with it and honestly cannot see a difference in shift patterns. I have put this down to the van being new and probably has a "break-in" engine/transmission program running for now. Shift patterns are not great with this transmission. Short and long shifts at same throttle setting. Cannot believe MercBenz was behind this development! Again hoping this will smooth with time.

Leary of high pressure tires. Tried this on my Taurus and Cherokee, and besides harsh ride, there are safety and control issues especially on wet and icy roads. I ran as high as 45psi which is unsafe in my opinion and gives diminished returns at top pressures, so I think your recommendation of 39psi sounds wise.

I work for Michelin so I get Michelin/BFGoodrich/uniroyal tires for free, so I will be looking into Low Roll Resistance tires, but I see choices for this van are very limited. I am open to recommendations...

I have been trying that, but this is a "fly-by-wire" system with no feedback to the pedal and the transmission seems to have a mind of its own. Darned thing will go to 6500rpm at 1/4 pedal in some gears and then shifts at 3000 in the next gear. Grrrrrrr! If I let off to get it to up shift, it will hammer back down a gear as I gently reapply throttle to accelerate. I expected more out of this transmission, and hope it will improve with time.

Pleased with the van over all. My 99 Caravan delivered 17 and 18MPG(imp) for the first tanks of fuel so the 2012 is already ahead of that. The 99 eventually went to ~30mpg(imp) after 20,000kms. This 2012 van seems to have lower rolling resistance (although it feels heavier) so I am hoping to get it up into that range.

You have given me some things to work on, thanks guys!

Steve

I just checked. In my 225/65/16 I can get Yokohama AVID Ascends, Goodyear Assurance Fuel Maxes and Michelin Defender Green Xs pretty easily. I'll be slapping a set of Goodyears on it before winter hits.

Funny, the Michelin site rates the Defender as an 8 out of 10 for fuel efficiency?
2012 Dodge Grand Caravan Canada+Value+Package Tires | Michelin Tires

My only winter choice (which I have to make soon) would be the X-Ice® Xi3.
2012 Dodge Grand Caravan Canada+Value+Package Tires | Michelin Tires |Winter Tire

It is rated at 10/10 for fuel efficiency. What is with that?
Winter tires are always less fuel efficient for various reasons.
I work for Michelin but I am a mechanical/electrical guy, not a tire expert.

Does anyone else understand this? (Defender 8of10 fuel rating vs X-Ice®Xi3 10of 10)

Steve

I drove one of those this summer, it does have quite good power, and the 6th gear is beautifully low :) High 20s cruising at reasonable speed on the freeway.

You would think so, what with the blocky, squishy treads. But it's not necessarily the case.

One of Nokain's winter tires has very low rolling resistance. They were used on the winning car (in summer) in this economy race: Modified Honda CRX HF Scores 118 MPG in Fuel Economy Run

I did an unscientific but "controlled as possible" comparison of all the tires I own, and one Michelin winter set scored 3rd best for rolling distance (out of 7 different tires), beating several all-season options: http://ecomodder.com/forum/showthrea...eet-19126.html

So I wouldn't discount snows for LRR.

I drove one for a few weeks and I was really impressed with the power! Mileage was about 19-20 mpg under combined city and hwy driving.

I'd love to swap one of these newer v6s into a much lighter first gen Caravan or Voyager to make a great sleeper lol.

Another graph of those first 10 tanks of fuel, Speed vs Fuelmileage:

http://sphotos-c.ak.fbcdn.net/hphoto...28974126_n.jpg

And for those of us who still think in MPG here is another graph of the same:

http://sphotos-f.ak.fbcdn.net/hphoto...45681491_n.jpg

I guess this is a messed up graph that would only make sense to older Canadians. MPG(imp) plotted against Km/h.

This sounds like a warranty problem. I'd complain to the dealer.

I am running generic 3 season tires on my minivan. Have been running the tires over 50 psi now for some time. Tires still are wearing very evenly Must have good seats as it rides comfortable and handles fine. It has the 3.8 v6. Still runs fine and gets 25+avg for the tank in warm weather. Ambient temps and wind are big factors.

One technique that works good for me is to keep the throttle light all the time. I don't pulse and glide Keep your instant mpg higher than your average.

No, it doesn't. Our transmission guy chased these "it shifts like ****" somplaints on a few vans before he noticed the button was lit up on the one he had that day. Turn off the Econ button and give it some time.

Remember: turning it on makes it resist shifting, and when it does it will skip gears. If what you're doing is going to require shifting and you want it to shift happily, turn off the Econ button and let the transmission work with all of its gears. If you have Econ on and push it hard enough to make it shift, don't complain when it shifts grudgingly.

The first time I drove it for more than a dump run was fully loaded with the family from NYC back to NH. There were a couple stops and I had the cruise at 65, but we got just over 26 for the trip. I'm really happy with what it gets, considering what a pig it is.

Sounds like good advice, I'll try it with econ light off from now on.
Electronically shifted transmissions all seem to have a learning curve and modern electronic engine controls have break in periods built into them, your advice doesn't surprise me. Thanks.

Steve

Econ light "OFF" seems to have solved all the transmission problems!
Thanks guys!

Wow, much better shifting in our hilly terrain with the ECON off.
Pushing the button does not result in instant changes, so beware.
I suspect that my fuel mileage will be better in this hilly terrain with the ECON off.
Actually holds in gear better and does not do the huge jump shifts.
Ramps up through the gears better too on acceleration.

Several low tanks are the result of severe local trips. 2-10kms on cold engine.
Temps are dropping here too, -8c this morning. Engine does NOT warm up on light loads.
Temp gauge should be at half, sits at third. Will likely do grill blocking for winter.

Driving fairly normal at this point, no P&G, mostly cruise control where able.
Under 70kph driving is stop and go city driving unfortunately. Kills mileage.

Steve

Is it really 4500 pounds? Do you have a fuel economy gauge? 50 psi in the tires?

Remember it is hard to compete on an economy basis with some that live in the south. Temps play a huge factor.

Yes, not only does the temp have an effect on rolling resistance and engine warm up, but the fuel is changed seasonally as well.

Don't know actual weight, have not weighed it. That weight is from published specs.
This van does have an OEM on dash L/100kms indicator. Its tank to tank values are in light green on the graph below.

Tires are at stock pressure as of yet. Will be soon switching to winter tires with the change of weather.
For the most part I am base-lining the vehicle in its initial miles.

Here is the tank to tank mileage so far. The low (high?) spikes are from short distance trips.

http://sphotos-d.ak.fbcdn.net/hphoto...59463238_n.jpg

Pump those tires up! It is the biggest bank for the buck.

Assume the rule of thumb that with driver and full fuel the weight is 450-lbs above factory shipping weight. Using a certified scale (three pads) works best. Wheel-by-wheel is recommended as this is a vehicle with cargo capacity (and a fairly substantial towing ability, beyond the factory rating) so that knowing FF and RR plus wheel-by-wheel under various conditions can be the aid in load versus pressure for tires.

The air-conditioned go-kart crowd doesn't quite understand that higher COG and widely varying loads means that tire "give" is integral to best braking and transient response with a van or truck.

Staying within the factory range of pressures, but dialling in the tires to maintain the 15% load reserve (see CapriRacers site) works very well on my pickup. To the tune of 120k on the first set of tires. Raising pressure doesn't always have a beneficial effect as it is more about the vehicle is being used, versus how the vehicle is being used. Keep that order, IMO.

.

I was looking in the door of benzilla today and saw the weight. 4500 pounds .. It was GVW not empty weight. I bet you are quoting gvw not normal weight.

Curb weight is listed at 4510. Not surprising, most new cars are really heavy cause of safety equipment.

Wow that is as heavy as my 05 Econoline! With close to the same economy and less capacity.

Must be some advantage to owning it?

mileage, looks, not a ford... should i go on? :p

I hope you are not taking offense to the fact that your car is as heavy as my Econoline, a true truck, my farm truck.

Put 'em on a scale, guys. Driver, full fuel and usual trunk junk. A stripper Econoline and a loaded minivan might be close. But what is the payload of each?

And, minivans are not lightweights. I think GVWR is near 6k on some.

FWIW, they are also not limited by the ridiculously low 3500-lb tow rating, Set up properly they are capable of much more. An aero travel trailer is bread & butter for a good one.

A pretty wide range of use where maximum payload is not the concern. Very good people hauler.

.