Another Hopeless Case. Ram Van 3500.
 

Hey all. I haven't posted much on here for a long time, since I was trying to crack 50mpg with my pizza delivery Civic. I've hit 48, so I'm getting close.

But.

We bought a van. '02 Ram Van 3500 extended. Basically the biggest van we could find. And it gets 12 miles to the gallon. We're planning on using it for road trips and such, so any degree closer to 20mpg will be fantastic.

I finally got the interior set up mostly how we want it (fixing the rear heater/ac was a bear); so now I can work on fuel economy.

Currently I'm working on a giant air dam and side skirts. Other ideas welcome. It's got all the "bad" stuff: automatic, 4.10, the big V8, etc.

I would look to commercial trucks for inspiration--smooth wheel covers, the side skirts you mentioned, and perhaps some sort of folding tail like they use.

You're rated 12 mpg combined. Jumping that pig up to 20 just isn't happening: I tried with an MT Xterra and only got 2-3 above combined.

A used axle with a better gear ratio can probably pay for itself, and figuring out a way to get that 46RE to lock up will probably be a good move. After that, keep the revs down and DWB, DWB, DWB. The main thing is actually reframing the way you think about it. Instead of seeing it as a low mpg failure compared to your Civic, ask what you're getting for your 12 (14? 15?) mpg. It's probably a lot. Sure, you want to improve mileage, but if you're getting the full utility out of it then it's a win.

PM me the last 8 of your VIN and I'll see what info I can dig up.

x2 - Maybe you could find a taller rear end for your van? Belly pan?

One other thing you might want to do, is to affix plexiglass sheets to the rear of your van, so as to get rid of the gentle rounded edges in favor of something more like this (like Vman455 was mentioning):

http://ecomodder.com/forum/attachmen...1&d=1453327555

The edges don't have to be quite as long as what's on that semi trailer above.

Yeah, the point of the van is to haul massive amounts of cargo (one of its intended uses is to facilitate a move), so I don't expect it to get 20mpg. I'm just looking to save a few bucks over doing nothing.

I got the airdam on yesterday, I'll post pictures soon.

My 2001 full size GMC van with a 5.0 V8 could pull down 20 MPG on the highway, if I kept the speed to 60 MPH. More like 17 at 70 MPH. That's pure highway though.

That said....
BOATTAIL!

I got this put on the other day. I'm also going to do matching side skirts and then paint them flat black.

Should I do skirts behind the back wheels as well? Also, will the perforations make a material difference?

I MAY be able to boattail it eventually, but all the mods I do have to pass the wife's aesthetic approval. Maybe I can fabricate a boattail that will double nicely as a small camping awning, and convince her that way...

I am reminded of the old Xplorer campers. I don't know if those aeromods amounted to any measurable increase in highway mileage, but they sure looked cool -- kind of.

airdam
 

Ahmed Feysal did a Master's Thesis doing CFD on a Dodge pickup.
His research showed a drag increase when the airdam had between 6"and 3"ground clearance.At 3"clearance (for racing only!) he got a 1% drag reduction,which would be hard to see at the gas pump.
If the van behaves like the pickup,you may see an mpg penalty.
CAR and DRIVER modded a Ram Van in he 1970's.If I remember correctly,the only thing which helped them was a mirror delete.
Mirrors from a Tesla S would show an MPG increase.

Im from a big family, so growing up we had the same van but a '93 model. Definitley look at semi's for inspiration as already suggested. Maybe creating your own peices around the top and sides to give a sharp break for the air to detach, much like the rear of a prius. I would also completely cover those rear wheels, they ride inboard of the body quite a bit if memory serves me.

Did you go through changing the fluids? Say, Full Synthetic 0w30 instead of conventional 10w30? Though after I did something like that the oil gasket on Dad's van started leaking. YMMV.

It's not so much that good fluids are the enemy, they just bring other problems to light. Those gaskets already leaked... The high viscosity fluids just couldn't flow through the gaps.

Yep. I'm just mentioning it so it's not an unknown in the thread.

Is a Diesel conversion out of question?

I have been going through and making sure all the fluids are changed and/or full (one of the joys of buying a used vehicle. I just put them all at stock specs, though; there may well be good room for improvement at the next oil change with some thinner oil.

I wanted a diesel. I wanted a Sprinter, but they're just way out of my price range. One day, though, I'll be rich and can afford to have everything I want...:P

I do plan on some rear wheel skirts in addition to body skirts, so that'll probably help too. Now if only the weather will be clear when I have time to do it.

What type of rear end does it have?
A gear swap may be feasible.

What about keeping an eye for a wrecked Chevy with the 6.5TD to swap it into the Ram Van? It may sound kinda odd, but its fitment seems to be easier than the straight-6 Cummins from a Ram truck.

I think changing the rear gears and, if needed, lightly modifying the engine to lower the torque curve will make very significant gains.

I remember the '93 3500 we had, i actually drove it in high school. It didnt matter much how you drove it, it never got more that 13 to 15 mpg. 2bbl tbi, no tach so who knows what the engine speed was. Had absolutely no trouble running any speed you wanted no matter what you had it loaded with, massive amounts of torque.

Sometimes replacing the cam or the headers does a miracle for that matter. Forced induction can also help under some circumstances.

Looking at the engine is a waste of time (other than to get it running in spec) until after he addresses the way the power gets used: aero losses, gearing and getting a handle on that 4 speed transmission. Changing the torque characteristics before you've got control over how the power output gets used is putting the cart before the horse- literally.

Correct, only modifying the engine if needed and AFTER changing the gearing.

RE: the rear gearing: I'm pretty handy-- i.e. I have no qualms about changing my own oil, installing aeromods (obviously), fixing something if it breaks, etc.-- but in the big scheme of things, I hate wrenching. So if the current 4.10 rear axle is in good condition (which it is, afaik, since I had it apart to change the gear oil), I'm not about to take it off to put in something that is an unknown.

Also, I don't have a shop, which makes any mechanicking project into a have-to-get-it-done-before-it-rains-again project, which sucks even more fun out of it (Hooray for the pacific NW...).

I'll keep it in mind for the future, though.

You might could consider a coolant-based intake air heater. Both my Dodge Dakota's 4.7L V8 and my Dodge Magnum's 3.5L V6 have taken really well to heated intake air, it's a lot easier to plumb than trying to take heated air off exhaust parts, and I think that coolant does a better job of heating air than exhaust components do. I can get 90 to 100 F air going into the engine, when the outside temperature here is 0 to 10 F.

Heated intake manifolds were widely used in dedicated-ethanol versions of Brazilian cars, though they had a limited usage in gassers.


Makes sense, but some engine tuning is still worth considering.

Are you certain you have 4.10 gears? I think you might have 3.92's. 3.92 would be 1787rpm @60mph and 4.10 would be 1867rpm @60mph. 3.55's were optional, 1622rpm @60mph.

Get me the VIN. There's a lot of information in there.

Does it even have overdrive? I thought the Ram Vans never got an overdrive transmission? Chrysler held on to the 3 speed automatics as long as they could.

At least in that model year, the 32RH was only available with the 3.9 V6. The 5.2 and 5.9 V8s came with the 46RE.

Mmm. Chrysler 4 speed automatic.

Better save for a rebuild if it hasn't been rebuilt in the lats 30K miles ...

Or save for a manual conversion, instead.

Nope, still figuratively. Literally would involve a horse and a cart

I had a manual Xterra. Trying to hypermile it was a waste of a good manual transmission. An auto may have been worse, but not by much.

Sorry I've been AWOL. Been working and working on remodeling the house...Yay, projects! Blah.

Anyway, here's the VIN, for what it's worth: 2B5VB35ZX2K119553.

No good. Maybe with 2B5WB...?

Some fun codes:
Build date: 1/29/02
A07 5.9L Engine(EML)/4Sp Auto Trans(DGT)
ADP Heavy Duty Suspension Group
BAZ Alternator - 136 Amp
BGK Brakes - 4-Wheel Anti-Lock
BKJ Brakes - 12x3.5 Rear Drum
DGT Transmission - 4-Spd. Automatic,46RE
DHA Torque Converter - Lock-Up
DJE Front Axle
DMF Axle Ratio - 4.10
DRC Dana M60/248MM Rear Axle
DSA Axle - Anti-Spin Differential
EML Engine - "Magnum" 5.9L SMPI V8
HAA Air Conditioning
HBB Air Conditioning - Rear w/Heater
NAA Emissions - Federal
NBK EVAP Control System
NFT 35 Gallon Fuel Tank
NHB Cooler - Auxiliary Transmission Oil
NHM Speed Control
NMC Engine Cooling - Heavy Duty
SFB Shock Absorbers - Front Heavy Duty
SGB Shock Absorbers - Rear Heavy Duty
SHA Stabilizer Bar - Front
SUA Steering Column - Tilt
TYT LT245/75R16E BSW ALL SEASON TIRES
Z3E GVW Rating - 8700#

The 5.9L V8 is a very thirsty engine. Its JTEC engine computer doesn't help much, in that regard, either. They tend to do excessive WOT enrichment if the throttle is depressed more than 1/3 open. Maybe there's some easy way of advancing ignition timing on it? Might also consider some sort of clamp circuit on the throttle position sensor, to make it not do WOT enrichment.

That may be it. I had it scribbled on my hand, so it could have been a U or W easily enough.

One option you will not like, drive slow, like 55-60 mph and the other is to raise the rear gearing to 3.73's from the 4.10's. I wouldn't go any higher due to weight of the vehicle.

Another option as was suggested before is a good air-dam and if you have the time and money a full belly pan under the vehicle.

The largest problem you have is the size of the van. There is no easy or cheap way to drop the Cd and or weight on that beast. :(

I am a very long time lurker and haven't posted much at all. However, I am also a big fan of full size vans and Dodge vans and vehicles. The four speed Dodge 46RE is a fine four speed automatic transmision that has a lcokup torque converter and overdrive. It is based on the old very reliable and sturdy A904/A727 design so you really don't have too much to worry about in terms of longevity. Making sure the bands are properly adjusted and good fluid is used is about all you need to do. Use the latest Dexron version, VI I think.

With 4.10 gears you will definitely need to use the overdrive on the highway.

The 360 Magnum is about the best of the old pushrod engine technology that Chrysler did. You won't find much in the way of efficiency improvements in that motor.

As has been mentioned above, the engine is already fairly efficient. Simple things like running syinthetic oil (5W-30, or lighter, maybe 0W-30 or 15 or even 10 if your pressure is good enough) to reduce internal drag, making sure your air filters are clean, making sure you have the correct temperature thermostat, etc...

Old full size vans are "dirty" from an aerodynamic perspective, but as has already been mentioned modifications like an air dam are actually more harmful than helpful in everyday driving. A bellypan might help, and some kind of a kamm-back modification, but really something simple like the standard luggage rack put on conversion vans might be enough to break up the airflow off the back of the van and reduce drag.

Your best options are to drive conservatively, reduce the weight of the van, and reduce parasitic losses from fat tires or too-thick oils. The only modification I would do to improve economy would be to increase the rear axle gear ratio to something like 3.9 or 3.5. However, you are driving a big heavy brick and the lower 4.10 gear ratio will actually help the fuel economy in town in stop and go driving.

I once had a 1984 Ford E150 full size conversion van equipped with a 351 high output engine (four barrel carb) and a C6 three speed transmission and a 3.5 rear axle ratio that I tuned to the point where I could get over 20 MPG highway if I drove conservatively. But where is the fun in that? I typically drove 75-80 on the highway and got mid teens in fuel economy. But the engine ran so lean that I melted the top oil control rings on all the pistons and had to get the engine rebuilt. That drivetrain powers my current 1989 Ford E150 that I converted to MAF based sequential fuel injection. It still gets about 13 MPG on the highway no matter how fast I drive, but runs smoother than ever.

My brother has a 1983 Dodge full size short wheelbase van that has a 225 slant six and A904 three speed auto trans that I have tuned to get about 15-17 on the highway consistently, even driving 60+ MPH.

Vans are built for comfort and work, not for max fuel economy. With a full size American gas powered van getting anything above 12 on the highway is a good accomplishment. Aero mods really won't help much unless you do LOTS of highway driving.

We have a 2000 Xplorer camper (based on the 3500 Ram Van) with the same mechanicals and typically get 9-10 mpg pulling an enclosed motorcycle trailer. I don't know what it'll do w/o the trailer but 12 would seem possible. The Xplorer has a 42" extension welded on, awning stuck out into the wind, large "trailer" mirrors and some weird-ass television antenna platform mounted on the roof. I typically drive 55-60 on the highway (O/D off) when towing and as much as I'd like, I don't expect much better mileage ever. The issue with these big vans is simply lousy aero and a lot of weight. I changed rear differential fluid to full-synthetic and didn't notice any change in mileage at all.

I do try to minimize weight by not completely filling the water tank, etc. but it is what it is and it's hard to expect better. I plan to remove the antenna platform but it's pretty hard to work on the roof and I worry about water leaks. The best solution is just slow down as much as you can get away with. It's a great tow vehicle and I use the built-in generator to charge my bike at the dragstrip (electric race bike.)

Not sure when the 46RE torque converter is told to lock up, but...

On my Dodge Dakota, torque converter lockup normally occurs at 45 MPH. However, in OD OFF, lockup occurs at 35 MPH. Yes, it's a 545RFE, which is a different animal, but you might want to look into when lockup occurs for the 46RE in normal and in OD OFF.