Ideas to increase F350 MPG (DIY Cyl Deact?)

[oil pan 4]

A running Cummins engine costs several thousand dollars.

[Heihetech]

DCD stands for Dynamic Cylinder Deactivation. You have to install an
electronic device called DCD Controller, plus the required WBO2 sensors.

Originally Posted by 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!!!

[ChillyBear]

Saw this on my local CL. (Not mine) but that's a steal for the right person.(TWO COACHES,ONE PRICE) Overland Motor Coach 42' CUMMINS 330 DIESEL

[Frank Lee]

Originally Posted by Heihetech

DCD stands for Dynamic Cylinder Deactivation. You have to install an
electronic device called DCD Controller, plus the required WBO2 sensors.

You're still alive? Sell any DCDs yet?

[RCB]

Originally Posted by oil pan 4

A running Cummins engine costs several thousand dollars.

If you keep your eyes open, you can find a decent runner for around 1500-2000. The adapter plate will be 1200-1700 new, but again, keeping your eyes open you'll find used ones in the 500 range.

I've done a 4bt swap on my Ramcharger, but to do it again, the 6bt is cheaper and easier. The MPG difference is only a couple MPG between the 6 and 4 as well... plus the 6 is much smoother.

Another option you may consider is trading for a 1/2 ton with a tandem axle trailer.

I have a 1 ton wood truck (chevy) that used to have a 454 in it, but prior to my owning it, had a 350 swapped in. I get 16-17 unloaded and around 13 hauling a tractor or full load of wood but it is as slow as pond water. That doesn't bother me though.

It'd be a bit of work, but one of Ford's best truck engines (IMHO) is the 352. I've had it in two different trucks in the past. A 66 1/2 ton got 20 MPG all day long loaded or unloaded. Also had one in a 73 1 ton dump truck and it got about 13 but it was geared very low and carried around a dump bed all the time.

[Poodwaddle]

Originally Posted by csnyder

Another friend repowered an F250 4X4 with a Deutz air cooled diesel for use in Belize.

Down here in Central America about a quarter of all vehicles are diesel. Landcruisers, Nissan Patrols, Isuzus, Mazda trucks, all asian brands have diesels that I have never seen in the US. There are just so many more options for diesel repower. Unfortunately it is VERY corrupt down here and prices on everything are higher than one would expect.

[RCB]

Yeah, Isuzu diesels can be had cheaper, but the flip is you will likely be making your own adapter plate. If you have your own mill, not a problem.

You can find Mercedes diesels, but parts are expensive here. I've not seen many (any) Mazda diesels here. It seems Isuzu has the lion's share of the import diesel market here. I wish we could see more diesels here. The new emissions regulations are hard for diesels to meet and they loose efficiency while doing it.

Ultimately, your easiest (also likely cheapest) route is a supercharger on the 460. You'll probably pick up 2-3 mpg. As long as you keep boost around 5psi or so, even if you don't have forged internals, it'll likely hold up. I personally like roots blowers over centrifugal for trucks. Roots gives you more HP and torque down low where trucks need it.

[oil pan 4]

A supercharger is not going to increase fuel economy on a gasoline engine.

[kerryp]

IMHO:
Cylinder deactivation should work. I would not worry too much about heat balance. Cannot be worse then starting a cold engine! The coolant and heat transfer should keep the unused cylinders from getting cold.

I am mostly theorizing here....

U stated two Oxygen sensors....Either one per bank or one before and after catalytic converter. U could fool the computer by simply supplying a 0.50 Volt sources instead of the sensors. Better yet, take a measurement before "throwing the switch" and duplicate the voltage.

U mentioned changing the injection resistors... DO NOT DO THIS. That model year PROBABLY uses batch injection. The cylinders are divided into odd/even. Simply cut off the supply voltage to one batch with a simple off/on switch.

If U R using a MPG gauge, and notice a worthwhile improvement.... U can build a simple circuit that alternates deactivation between the Even/Odds automatically, every minute or so. Your temperature sensor may favor one batch over another depending on its installation location.

GM claimed 10~15% improvement with a true system. On the Fiero Forum, 23MPG Vs. 28 with DOD, which was renamed Active Fuel Management.

Good luck, keep us posted on your results.
Kerry
AG4YW

[Poodwaddle]

Originally Posted by oil pan 4

A supercharger is not going to increase fuel economy on a gasoline engine.

My understanding is that a supercharger allows a manufacturer to use a smaller engine (squeeze adequate HP from smaller engine) and thus improve MPG. But a truck with an already oversized engine would not benefit. Yes, it would get a few more HP and the engine would possibly run a bit more relaxed, but not significantly and the supercharger would push more air into the engine and draw in more fuel, so all benefit is lost. Is this right? Or have I misunderstood the way it works?