Fuel economy mods

[FordGuy100]

Alright guys, I'm liking all these ideas coming in. So I will go and fill up tonight, top it off, so we can get this underway. I think I will drive for 1 week between all the mods I do. I'll start off this week by driving around like I have these past couple months. I will drive my regular style, so that its more accurate.

Here is what I'm thinking I will do.

Week 1: No changes
Week 2: Inflate tires to max pressure
Week 3: Get my G codes spray tested, remained if need be, and swap them in (I know I have one bad injector, I have a ticking sound that sounds like an exhuast leak, but goes away when I let off the throttle)
Week 4: Synthetic oil in tranny, transfer case, rear and front diffs
Week 5: Intake, I'll build up a cold air style intake
Week 6: New thermostate, I think mine is going out
Week 7: This is where it gets expensive...

 

[Agnem]

Injector spray pattern is a big one. I can tell you I lost 4 or 5 mpg on the Moose Truck when I switched to DPS' injectors. I've never lost MPG due to an overdrive. I went from 20MPG to 23MPG on the Moose Truck when I added the GV. On flat ground at 55MPH I'm turning low teens, and the milage is really good. Compare that with the Moosestang, which spins at 2500RPM and no lock up clutch or TC, and it's getting 14. Of course it's really hard to tell on WMO, but as the pump has worn, and the timing has fallen back to the point now, where I can no longer keep it in the proper range, I think my milage is down to 12. So in my mind, the big hitters MPG wise are fuel atomization, timing, and low RPM's. Getting rid of extra weight always helps, and while many of us are installing larger tanks, that's more weight to carry around, so it may be cheaper to fill up more often, and haul less fuel and other non-essentials. I think tires are probably the next big area for improvement, as keeping tire to road surface contact to a minimum is bound to lessen rolling resistance.

 

[tonkadoctor]

Taking the driving habits out of the equation.

1. Tires make the biggest difference in fuel economy below 50 mph
2. Aerodynamics make the biggest difference above 50 mph

Cummins MPG Guide It's geared toward big trucks but well worth the read. There are many things here you can apply to cars etc..

Pulling travel trailers and fifth wheels I see a weight as a non issue. In fact I get better fuel economy hauling high profile 12' tall 9k-11k luxury fifth wheels than I do with 5k - 6k 10' tall travel trailers unless it's one of the new wedge shaped trailers then it's about the same as the fivers. It's all about the aerodynamics there. Less cab to trailer gap on the fivers vs the TT so the aero works off the truck.

My truck scales out at 9050 lbs with 125 gallons of fuel and all my gear with me in it, gets the same as before I installed the fiver, GN, gear, toolboxes and aux tank. I did try running my tires at max 80 psi for a month instead of 55 front 65 rear. not a noticeable difference in fuel economy but can tell you for a fact that the handeling and ride sucked big time. Handled like a duece and a half in the rain, on pavement at 55mph, always felt like I was on ice and when it was icy or snowing, fugedaboutit

Slow down, don't jack rabbit start and keep your tires aired up properly it's the cheapest most cost effective and proven mod you can do.

Why do you think I usually drive between 55 and 63 on the highway loaded and empty. It's easy on fuel, easier on the truck and easier on me. Just because the speed limit is 75 in some states it doesn't mean you have to drive that fast. Sit back, relax, get in the granny lane, set the cruise and enjoy the ride... then watch the same cars and trucks, that are flying down the road, pass you over and over again and only beat you to their destination by a couple seconds if they beat you at all

Save your $800 for SVO or WMO conversion, it'll be the best return on investment. If you put the $800 into other mods hoping for better MPG and it only goes from 16 to only 17 mpg it will take 50,000 miles to recoup the money spent at $4.70 per gallon.

Now if it gains nothing for fuel economy you are SOL for $800 and if it goes the wrong way ...... well you do the math.

 

[FordGuy100]

Taking the driving habits out of the equation.

1. Tires make the biggest difference in fuel economy below 50 mph
2. Aerodynamics make the biggest difference above 50 mph

Cummins MPG Guide It's geared toward big trucks but well worth the read. There are many things here you can apply to cars etc..

Slow down, don't jack rabbit start and keep your tires aired up properly it's the cheapest most cost effective and proven mod you can do.

Why do you think I usually drive between 55 and 63 on the highway loaded and empty. It's easy on fuel, easier on the truck and easier on me. Just because the speed limit is 75 in some states it doesn't mean you have to drive that fast. Sit back, relax, get in the granny lane, set the cruise and enjoy the ride... then watch the same cars and trucks, that are flying down the road, pass you over and over again and only beat you to their destination by a couple seconds if they beat you at all

Save your $800 for SVO or WMO conversion, it'll be the best return on investment. If you put the $800 into other mods hoping for better MPG and it only goes from 16 to only 17 mpg it will take 50,000 miles to recoup the money spent at $4.70 per gallon.

Now if it gains nothing for fuel economy you are SOL for $800 and if it goes the wrong way ...... well you do the math.

Thanks for that site I will check it out.

I think its worth it to further the knowledge of everyone, as to what help, and what doesnt. To be honest, if you look at the things I listed for each week, they are things I need to, or was going to do anyways. This way I will do them, like I would otherwise, and then report back the fuel milage.

I'm also going to add that I will do a Racor Fuel water septerator, because my stock one isnt draining, and the light in the cab blinks on when I hit a bump or accelerate hard. I will have to do that one fairly soon. Then I will change my oil and add Auto Rx in as well, I need to do an oil change, and I'm hoping the Auto Rx will decrease my oil consumption, so when I switch to synthetic, it wont burn much (I'm burnign a quart ever 500 miles) .Actually, I will have to do the easy ones first, becuase finals are coming up and they are going to take away my weekends so I can study for them.

Plus all the things I've listed so far arent all that expensive, I'll probably spend a couple hundred, which I would have anyways.

 

[tonkadoctor]

The single biggest improvement on my IDI was when I swapped out the 4.10 for 3.08 gears. went from 18 mpg to 22 mpg avg. Did get just over 23 mpg once.

Made the truck into a dog for power but it was a huge differerence in fuel economy. GV would have been a better choice but It was a cheap way for me to do an experiment with my buddy providing the labor for the swap and it was only a 2wd.

 

[69dieselfreak]

an OD is only going to mess you up on fuel mileage due to being in the wrong rpm range when you are towing. I found that on my truck I get better fuel mileage towing my 5er in 4th than in 5th, even though 4th is wound out ( but pretty soon I'll have my Spicer 3 speed Aux tranny in there and I'll be able to split those gears and I'll have a nice gear right between 4th and 5th that'll be just right


---------Robert

can u give us some more info on that 3 speed aux tranny where we can get one how much and will that make our trucks be twin sticks i have the 4 speed tranny will that work thanks a bunch

 

[BigRigTech]

My truck has 3.55's with the ZF, 2000RPM at 70mph. Waste oil isn't yielding as good fuel mileage but it's free so I don't care....Here's an easy tip - if you have any junk in your truck then get rid of it - lighter is better....I'm stilling running the stock tire sizes - nice and skinny makes less rolling resistance.

 

[subway]

something else not mentioned is alignment, this can really add to the rolling resistance of a vehicle if it is out. make sure your rear brakes arent dragging to much either and the wheel bearings are nice a smooth.

ALLOT of power gets eaten up in heat going through the drivetrain gears and bearings. personally i would rather see a single transmission set up like a ZF-5 or even a six rather that a second transmission with extra bearings and gear to run through. gear vendors OD's are strong and in themselves much better than a straight 1:1 with a T-19 or C-6 but i would suspect less efficient then a regular OD tranny.

you want to cut out as much parasitic loss as possible, how about a bed cover and lowering your truck to cut down the frontal area and turbulant air underneath.

just be careful how much you throw at making something more efficient, what are your paybacks for the money spent. it could be far eaiser and cheeper to just let it be and pay a few extra bucks dpending on what you do to it.

 

[riotwarrior]

Waste oil isn't yielding as good fuel mileage but it's free so I don't care....

This is a very good point....WMO or home made bio fuel or chicken fat etc if it is substantially less expensive or free...then taking a fuel hit is ok because free...is always and I mean always better n payin...if it works that is....

Free and stuck on roadside cause of some failure induced from "free" whatever it may be is not good....

The main reason I want the Bronco to have an IDI is no computer and it is friendlier towards bio/WMO/WVO conversions. I could just as easily geared up for a PS swap...IT is the used oil that has me for the cheap....

 

[FordGuy100]

So I went and filled up. I've been driving around on my front tank this last week. 30 mile commute each day, and guess what, it only took 3 gallons, thats 50MPG.... Looks like it was pulling from the rear tank, and a little from the front. Hopefully that fixes itself, cause it will skew the results.

 

[Diesel JD]

Stupid selector valve sucks. Mine failed in that manner as well. Not a real fun thing to work on either. MNR used a mechanical one which sounds good but his setup sounded way over my head.

 

[RLDSL]

can u give us some more info on that 3 speed aux tranny where we can get one how much and will that make our trucks be twin sticks i have the 4 speed tranny will that work thanks a bunch

If you do a search in this forum theres a past thread ot two with some links. Spicer made some three and four speed aux trannys 3 with under dir and OD and 4 with deep reduction , under , direct, OD, in various ratios and in iron or aluminum cases I have sheets with all the specs of the various boxes on them I suppose I could scan those, if you PM me your email addy I could send the sheet( might be a day or two )and i have the entire spicer collection of repair manuals for al of the transmissions, auxiliaries, ans PTOs or that era

 

[TLBREWER]

Mike

That's good info to know on the difference between TT's and 5ver's. I would have thought the tall 5ver's to be much worse on mileage. That may be another thing for me to consider when it's time to buy. The drag factor was actually one of the reasons I was shying away from a 5ver. Who knew.

Tom

 

[tonkadoctor]

Mike

That's good info to know on the difference between TT's and 5ver's. I would have thought the tall 5ver's to be much worse on mileage. That may be another thing for me to consider when it's time to buy. The drag factor was actually one of the reasons I was shying away from a 5ver. Who knew.

Tom

Just bear in mind I'm talking about the most common shape avg 3/4 ton towable TTs like my Fleetwood Wilderness that's shaped about like a brick.

 

[typ4]

Justin ,I would look for a zf 5 asap. Synthetics are good in the gearboxes. I got 19.8 on the last run to Seattle fairly empty, tools and such, maybe 800 lbs in the bed. Cruise on at 60 and I was happy. My biggest fuel user is my right foot.