Power vs Efficiency

[burtcheca]

I know there are many here that have modified their IDIs, adding systems or devices to increase the power. That's good if what you need is more power; but for us, the few that still run their IDIs as they came from factory: What do you think would be good to modify or add, just to increase mileage per gallon of diesel and/or biodiesel or oil/with whatever other additive or thinner you use. Remember, we are happy with the power they have with the factory set up, we just want to know if after years of research and experimentation anybody found some modification, or gadget, or reconfiguration of a part, that makes them more efficient.

Thanks, Burt.

 

[pybyr]

I wish I could offer something, but will eagerly follow responses, as I am coming from exactly the same place. I'd be willing to even take a modest drop in power in exchange for a boost in efficiency. I'm also coming from a place where any mods have to pay for themselves in a reasonable period of time based on fuel savings. Thanks.

 

[gatorman21218]

All ive got besides a properly tuned fuel system and a turbo is a gearvendor. If youve got 4.10 gears (or even 3.55s) a double overdrive can drastically reduce your rpms at highway speeds which saves fuel. Other than that all i can think of is the normal "shed weight, slow down inflate your tires" advice that AAA gives out

 

[crashnzuk]

I would think airflow. Ported and polished heads, headers, large free-flowing exhaust, and a ram air set-up. This would be on top of a properly functioning fuel system of course. Also, gear the truck to be in the thick of the torque at the speeds you want to drive it, figure out the sweet spot and stay in it.
Travis..

 

[gatorman21218]

I'm also coming from a place where any mods have to pay for themselves in a reasonable period of time based on fuel savings. Thanks.

X2 If something gives you an increase in mileage but costs 1000 bucks to do it, you might as well not do it. Remember too that these are 3/4 or 1 ton trucks not a sedan. You dont buy them for the fuel economy.

 

[Diesel JD]

Burt, I'm still trying to find add-ons to increse fuel efficiency. So far swapping to taller gears, a manual transmission, turbo, etc hasn't really helped my fuel mileage that much. You need to be sure your fuel system is giving you all it can. You probably already eliminated any leaks you had, but you could have your injectors pop tested and have the timing set and the fuel system replaced if the need is there. If you could find a GV or a DNE2 box for your C6 then it would greatly improve highway fuel economy, but the cost would be high enough that you might never make it pay for itself or if it did the payoff date might be in the distant future. Do you do most of your driving highway or in town/suburbs? Based on your chosen lifestyle and your location I'd guess mostly highway, but I can't be sure. My offer to time your truck for free stands if you bring it to Gainesville. It's not too hard. I'd want to make sure your #4 or #1 glow plug comes out easily. I'd be very upset with myself if I hurt anything of yours. For what you want, at a low cost I'd look at timing (no cost)
free flowing exhaust and muffler(cost..not sure, returns also depend on a lot of factors I don't know about)
Chop out the "soup bowl" on your air intake lid if it's still there...no cost except for time.
Usually I'd recommend pulling and pop testing the injectors but I know you want to keep on a budget and pulling these out of the van would be tough. You have to do it if the fuel economy is bad or you're seeing an excess of smoke, but otherwise, you might think about leaving it as it is.

 

[CDX825]

Bigger exhaust helped me the most with power and mpg.

 

[burtcheca]

This is what I have: '86 E350 custom/cargo van,weights 9,000 pounds, 6.9 original engine configuration with only 27,000 miles on it, C6, no smoke, runs smooth and with a lot of power (can see a little of white smoke when pressed hard and it jumps), ride must of the time dirt roads (cannot go more than 40) and highway (usually 55) with moderate loads (700-1500 pounds on it), tires at 75, all. Kind of tall and bulky looking. And it will never makes more than 15 MPG of diesel. I would be more happy if there is something I can do to have the same performance, and making 20 MPG.

Maybe I'm asking too much and I should consider myself blessed the way it is, and be content.

Thanks for the replies, there are some ideas you guys gave me that I can try. Like: remove the muffler and install straight pipes, remove the "soup bowl" and put a system like the one we had in the "muscle cars" in the '70s that you hold the filter in place with just a plate on top and is open all around; check timing, check injectors, etc.

I need to know how to post pictures here. I did it once and I forgot. I'm trying again now, if you don't see any is because this computer is smarter than this old Florida *******.

Thanks again, Burt.

 

[grog85]

The only mod I've done to mine is to add a 3 1/2" exhaust and redo the y-pipe to a more free flowing design. I've been meaning to post pics, but need help doing it. but my mpg is between 19 & 21.8 on recent fillups. Combo of city & 65 mph hwy driving.

 

[BigRigTech]

Keeping the rev's down is the key, 2000rpm or less cruising....3.55 gears work well....Goofy gets decent mileage with his F250 but he drive's it reasonable to get it.

 

[burtcheca]

grog85, 19-21 MPG, that's great!

I'm excited to try taking the stupid muffler out and have two straight 3" pipes installed. I need to know where to get the pieces that make the transition between the manifolds and the 3" pipes. Maybe I need to take it to a muffler shop, I hope they will not say I cannot have it without muffler because is against the law. Well I'm not going to worry, I don't live in California, thanks God.

Can somebody help grog85 and I with instructions how to post pics you already have downloaded as pdf files in your desk screen, please?

grog85, are you a redneck like me? I mean, somebody with very little knowledge in how to use a computer.

Thanks, Burt.

 

[Diesel JD]

The white smoke tells me you either have a few weak injectors/bad spray pattern, low EGTs or the timing is off. 15 is all you can expect in town(if you're lucky) but a bit more on the highway is not all that far off. 20mpg seems pretty unlikely unless you get an overdrive transmission or some sort of auxillary overdrive in there. 9000 lbs empty is a lot to move. My truck is only 5200 empty and I consider myself fortunate to get 14 mpg in town. On a long haul if I kept it to 55 all the way I bet I could get close to 18 empty. I know my truck needs another gear and have the brownie for that, just have to get it gone through and find the time to install it. Not going to be an easy project.

 

[Diesel JD]

Burt, you could probably bypass the need for an exhaust shop and with connectors off the shelf at Napa could make your own true dual exhaust 2.5 or 3" OD pipe and use the straight exhaust tubing from there. I'd think the only trouble you might run into is getting the bends made for exiting at the stock location and on the opposite side of that. Bear in mind without a turbo these things tend to really cackle on straight pipes.

 

[david85]

Is this a cube van?

 

[burtcheca]

No, it's a custom/cargo van.