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Old 07-12-2016, 03:27 PM   #1 (permalink)
F350DAN
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Ideas to increase F350 MPG (DIY Cyl Deact?)

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!!!

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