HI All,

Been running my 1994 E350 15 passenger van for awhile for work (I do deliveries) .... typical cargo probably about 2000 to 2500 lbs or so.

I had a Sprinter van before (it was longer and taller than mine so I loved the extra space of that vehicle and the 24 MPG that it could get BUT it got in an accident (not my fault) so it is basically gone so I thought about modding my Ford Van to be "better" (even maybe to the point of adding a High Topper from the junk yard).

Anyways, I typically average 19 MPG ( mostly highway running) but since diesel fuel is so expensive I was thinking of trying to install a Dana 60 from a 1990 Dodge truck with Cummins engine (3.08 ratio from what I've read (I know where there is one for not a lot of $$ since the man just wants the shell or the truck off his property).

Other than maybe having to fab up mounting points etc ... will there be any issues (unforeseen) that I may encounter ? I am not going to be over stressing the tranny with the higher ratio will I?

Has anybody done anything like this before ? What kind of performance / MPGs might I get from this?

( FWIW I am trying to stay IDI rather than getting a newer Powerstroke van ( I had a 1997 van that could get 20 MPG at 60 MPH But they are Sooo much more $$ if injectors or other work is needed)

Thanks

Andrew

 

I basically had the same concept as you back in 2012. I wanted a diesel van. Sprinters were tens of thousands of dollars, and a late 80's IDI van was $3000. The choice was simple.

I added a turbo, a gearvendor OD, installed LRR tires, and put in the 3.55 axle. Now I can get 22mpg if I keep it 55mph on the highway. If I go over 70mph, I get around 19mpg. I did a bunch of other eco-mods to my van to make it more efficient:
https://www.nickpisca.com/diesel/tur...-idi-vehicles/

You could probably get a few more mpg if you installed a manual trans (using a E150 gasser donor to get all the linkage and pedals).

I think a GVOD is a better choice than trying to adapt a 3.08 axle, cuz with the GVOD, there isn't any custom fab. just swaps out the tailshaft housing.

 

The efficiency of diesel engines doesn't vary much with RPM, at least to the same degree as gas engines. My experience running IDI's is that fuel consumption is the same, within a margin of error, at 2250 RPM as it is at 3300 (load being equal of course). So changing the final drive ratio won't be worth the trouble. If you have a C6 trans, ditching it *can* make a meaningful difference in the thermal efficiency of the whole package, but you probably have an E4OD. If you're cruising at a steady state the usual "accelerate slower" advice doesn't apply. I'm not an "eco modder" or anything by any stretch, but I'd imagine the low-hanging fruit in your case would be smaller tires aired up to 85-100 PSI. This would cut the air resistance of the body, since it's lower, and also decrease rolling resistance. Incidentally, it could also decrease the cost of tires.

 

HI,

WOW thanks for the great link ... did lots of reading!

I would love to add a turbo and even saw one for sale for $1200 on marketplace not too long back .... I regret not trying to get it since they are hard to find.

I.m not sure a gear Vendors OD will work on my trans since I already have an OD tranny ( I think its a E4OD).... On the other hand I believe there was another add on OD by US Gear that may be able to be added on as a separate unit but those units are even harder to find I think.

While I have not weighed them yet (I bought a set of factory aluminum wheels for my van (1993) which I think were made by Alcoa .... supposedly great weight rating ( I bought a set of American Racing 8 lug rims .... they were a good bit lighter than the steelies my van had BUT for some reason they are max 60 PSI inflation so I think they are not as HD as a good set of Alcoas....) I think a fair amount of weight can be shed with good aluminum wheels.

In the short term I think I will mount up slightly larger tires on the Alcoas for a poor mans OD and free up the exhaust a bit (it is rusty and will try to find some 3 or 4 inch pipe to get a good free flow system made.

Did you find that advancing the timing helps with MPG ? I think there is a special tool to measure advance BUT I think I may try just bumping it up a bit ....

With Diesel here being $5.65 per gallon I'm looking to start adding some oil to the tank for less cost and more BTU's ... I'm guessing that should help fuel economy too?

Andrew

 

Andy, I’ve been interested in this for one of my vans. The 3.08 ratio is hard to find. They are out there tho. The 89-91.5 cummins rear with the 3.07 is a Dana 70 rear axle. Some call it a d71. And coming out of a truck you would want to install that gear set in a van axle as the pumpkin isn’t centered on the econoline application. At least that’s the case with my 99 7.3 van. So I have focused on the Dana 61.
Car-part.com does have a few late 70s early 80s van Dana 61 with 3.31 ratio. But it’s going to cost a bit more to get that axle to the 3.08 ratio and 3.31 isn’t a big enough difference to help.

I believe lower rpm’s will help reduce fuel consumption. It’s the reason these axle ratios were made. On the other diesel forum there’s a member Dave Whitmer that used 3.08 gears a gearvender od to give his rig a dbl overdrive. His setup got him 26mpg. And with a 6speed manual he could tow. Using a auto transmission you need to keep rpm’s above 1400 for proper fluid cooling.< you will want to research that # for your trans. Mine is a 4r100.

My 01 7.3 has an aftermarket balanced assembly (turbo), bellowed upipes, tuner, ebp delete, and I i shimmed my injectors it’s a work van I drive it hard and get 14-15mpg.