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.