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Old 12-17-2020, 12:02 AM   #1 (permalink)
Master EcoModder
Join Date: Jan 2012
Location: MI, USA
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92 Camry - '92 Toyota Camry LE
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Big Diesel, MPG increase ideas?

Been a while since I've been on the forum. With helps of tips here I was able to pull 38-44mpg out of my 97 corolla (26 epa average if I recall correctly) and I didn't have many mods on it, just driving style and making the vehicle in good shape.

Moving onto today... I bought a 1995 F250 4x4 with the 7.3L power stroke diesel (turbo version with no waste gate) with the 5 speed stick for hauling a trailer and doing work. I know generally trucks and mpg don't go together well but I'm wondering if there's any solid ideas.

Here's the basics I already plan to do:

Max sidewall pressure on tires (or slightly above)
full sythetic engine oil
sythetic oil for trans and axles (front has manual hubs so the guts shouldn't be spinning while in 2wd)
Front air dam (less air in radiator) atleast for winter driving to keep temps up so the diesel stays happy

Truck is not lifted, and does not have wide tires, and pretty sure the tires are stock height. Currently have a topper on it which I think should help, but I just drove it home today so no base line.

I watched a video about a programmer that the gives extra power and fuel mileage, my dad has a 96 and his experience matched what the guy said too. Then the guy went a step further upgrading exhaust size to keep exhaust temps down (death to diesels) and added a propane system. He claimed a 30% mpg increase (minus how much propane he uses). I guess the theory is propane burns hot and fast and helps the diesel to have a better and more complete burn.

I also picked up a cheap parts truck that has the same engine but is a 2001 with the larger stock turbo with waste gate, and inner cooler. I plan to try to get the truck to run first before robbing parts off it.

I'm trying to keep the truck somewhat stock looking, and also keep it's function as a truck. I burn wood to heat my house, so the plan it that it will be my new wood hauler and I'm planning to buy some heavier equipment, so needed the bigger truck.

Truck only has 190k and the engine sounds nice and tight, no hard knocks like the 7.3L's tend to get with higher miles. An elderly man had it and I think the turbo might be carboned up some since it seems like the turbo takes longer than normal to spool up.

I'm kind of thinking a belly pan might be a solid option, I live in the rust belt, so it might keep some of the salt off the body. Also planning to not drive the truck often, so I'm thinking of some sort of system to keep the batteries topped up to have less load on the alt and prolong the life of the batteries.

Front tank seems to be around 15 gal and the needle moved about 1/8th tank for 100 miles, I know not accurate at all. Assuming it's close to moving to the 1/4 tank spot, that's 3.75gal or 26.6mpg. Seems too high to me but I'll have a better idea once I drive it a bit more. The trip was mild country driving, then express way 70mph (I know slow down and mpg goes up, I had my dad following, so was on his time too).

I haven't looked too much into mpg instrumentation, from what I read it's OBD1 so MPGuino might be the main option for me, not sure how well it would play with these injectors though since they are oil pressure + electronically controlled.

Anyway that propane system is quite interesting to me, knowing how much propane it goes through is a big factor though. I plan to convert some of my yard machines (riding lawn mower, generator, etc) to propane, so currently in search for a used 500-1000gal propane tank, then I can put a nursing valve in it to refill other tanks myself, and buy the propane in bulk quantities for a pretty good price. My last fill up for my tiny leased 250gal tank was $1.45/gal, if I owned the tank it would have been $1.35/gal. Propane is my backup heat, I use atleast a tank a year purely for home heating, hot water, etc.

Long post, congrats if you made it to the end of my rambling =).

Last edited by MetroMPG; 01-20-2021 at 01:09 PM.. Reason: (added pic to post)
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