Ideas to increase F350 MPG (DIY Cyl Deact?)

[F350DAN]

Hello All!

I have a 96 Ford F350 4x4, 7.5l (460), Manual with MAF.

I have another vehicle for daily commuting and non-hauling needs. But when I go to haul with the truck most of the time I am nowhere near maxing out the hauling power and I would like to get some more MPG with little loads and when going to pick them up.

I got this truck because I will soon be moving out to my cabin and hauling my own water which will effectively use the power of the engine, and when Im hauling a near maximum towing load I dont mind low MPG. However often times when hauling a light load or going to pick something up and I am empty I would like to see if anyone has any suggetions to increase MPG.

I am currently tuning up and refreshing all the components of this old truck. I also am driving using as many hypermiling techniques as I feel comfortable with. Many suggestions such as aero covers, or weight reduction, etc are not possible as this is a work truck. I would just like to see even 15mpg when empty haha.

The only thought I have had and please let me know what you think is a DIY cylinder deactivation. Now I see many threads on that, but I have a different idea than other threads I have read and intereted in your input. First it would be a purely electrical bypass setup as I do not want to mess with engine internals and sadly there is no bolt on kit to purchase for this engine. Im thinking adding resistors and bypass contacts to all of the fuel injectors as well as the (2) o2 sensors and having a small control panel in the cab. So I envision a switch that is power mode and economy mode. Power mode is exactly what it is right now stock. Economy mode will engage the o2 sensors resistors to fool them into reading a perfect a/f ratio (this i think is needed since I will not be closing off cylinders and the extra air from them will give the sensors a false lean reading and dump in extra fuel to compensate negating what im trying to accomplish). At the same time I will engage half the fuel injectors resistors (exact cylinder numbers to be determined) so half of the engine will not be getting fuel. Now I also envision some sort of relay or timer that will switch between half the injectors and the other half every cycle or every minute in an attempt to keep the wear and temps even.

Firstly I am interested in opinions on the concept only for the time being. The exact relay or programming logic to sucessfully switch between injectors can be determined later on as well as which cylinders to deactivate at one time.

Also I understand there will be pumping losses with this setup. As I stated im not interested in fabricating my own hardware to completely shutoff the valves to a cylinder.

So what do you think?.. Is it at all a sound proposal? Will the pumping losses to be too great and not worth any of this effort in improving MPG? Also I understand by cutting half my injectors I will not be getting 2x my MPG, but in your opinion what increase could I expect? 10%, 20%, 50%? If the increase is not enough then I am not much interested in pursueing this option.

Thank you all very much!!!

[Frank Lee]

1. Cylinder deactivation REQUIRES valve deactivation. Without it you can expect minus numbers for mpg improvement.

2. 460 Fords get the same mpg fully loaded or completely empty.

[oil pan 4]

For cylinder deactivation to really be worth it you need to be able to collapse the lifters and close both valves in the cylinder. With the valves opening and closing trying to move that air in and exhaust out it feels like the engine is misfiring badly.

What I did to double fuel milage on my carbureted suburban is:
Tune the engine for lean burn during cruise, lean at or near WOT is bad, you need to run rich during higher power situations.
Adjust the timing properly, does it have EGR?
Use EOC.
In the winter I took the fan off my engine to speed up warm up times and I am going to switch over to electric fans. In AZ, during the summer in the city an electric fan may not be a good option for you.
I also made a switchable warmed thermostatic and cold air intake, the thermostatic side is too small for WOT use.
With fuel injection you should just be able to use a traditional warm air intake.
You can change to a numerically lower rear end too.

[Frank Lee]

It's 4x4.

[oil pan 4]

I have always said that 4x4 is more expensive.

[Frank Lee]

Cuz he'd have to change the front axle too.

[Poodwaddle]

Change tires to a smoother road tread, something that you can put higher pressure into. If you increase the tire circumference you effectively do the same thing as a rear end reduction (except that most larger tires weigh more). Pull the mirrors in when you know you will be on the highway. Partial grill cover perhaps. Remove any aero-no-nos like cab shades and bug deflectors. If you have construction skills I would say build a 3 foot folding partial fishtail (top teardrop) attached to your cab roof and covering your bed partially when you can. It could fold down against the back window, or perhaps fold up over a load. You could also build partial side shouds but I am not sure if any of this would make much difference...be fun to experiment though.

[Fat Charlie]

Originally Posted by oil pan 4

Use EOC.

Lots more work, nothing to show for it. Even light P&G is an exercise in futility with these pigs. Smoothness and throttle precision are your main tools here.

The only good news is that it's a 96, so an SG or UG should work- unless HDs were somehow allowed to slide for a year or so from OBDII. With instrumentation, all the standard benefits apply- FE isn't simply abysmal, you can see exactly how abysmal it is and make slight tweaks with foot placement and gear selection.

That's not entirely correct- the other bit of good news is that it's a manual.

[Natalya]

There is aero you can do that won't affect the bay. Smoothing out the underbelly with coroplast panels or making moon covers for your wheels should help a tiny bit.

A kill switch for EOC... I can't see why this wouldn't be helpful, especially on down-hills. Do the injectors cut off when coasting in gear?

[ChillyBear]

Clean the dpfe and egr valve, it's an old ford, that's like half of your mpg if equipped.

Edit, I read further. Its a 460, if it has egr, clean it twice. Helps for economy mode/lean on cruise/ mpg highway mode whatever it's called. I'm guessing it's "heavy duty" if it has an economy mode after 1996.

Side note, I've noticed old escorts like having 10-20% ethanol, no clue on the 460's but they are so sooty, that even if there is no mpg gain like an escort, the carbon removal is good on occasion. Different bores/strokes obviously, but I like all fords with D-shaped heads.