I have also found that fuel additives do nothing for mileage. I quit using them altogether.
As for intake and exhaust mods, remember that these are simply allowing more air in and more air out. Nothing has been changed in the PCM programming, so theoretically the same amount of fuel is still being delivered. Diesels do not have set air/fuel ratios, so if you stuff more air in, it isn't necessarily going to change the rate of fueling. That's done with a chip or tuner, or seriously backing off with the right foot. If you're driving for mileage (meaning you are taking it slow and easy), an intake and exhaust do absolutely nothing for you. The stock system is more than adequate to flow enough air and exhaust to handle low power/low load situations.
I never pay attention to company claims of mileage gains or HP improvements. I listen to the average Joe user and find out how they like the product and how well it performs in the real world. That's where all my mod decisions were based from (except for the lift, previous owner is responsible for that).
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Curtis
2002 F-250 PSD
Best time: 15.3 @ 86.8 MPH at Bandimere - 9/10/08
Are you serious, that is amazing mileage and the only way it will get any better for you is to put your truck on the back of a tow vehicle.
I coast down hill and let off the gas the second I see the green light change to yellow. I literally drive like a grandma to the point I get flipped off getting on the freeway since I'm accelerating so slow. I'd kill for 18 MPG.
Yeah I get made fun of because I drive very slow on the side streets and usually 5 miles below the posted speed limit on the hwy. My wife thinks I am "weird" for folding in the side mirrors.
I have noticed that when I am down at South Padre, my MPG drops to about 15. When I am in the higher elevations like Denver, I usually run in the 22's without even trying.
BTW I don't rely on the computer, I just divide mileage driven by gallons used. Oh and I don't turn on my AC. I roll the windows down a little bit and open the rear window so it won't drag so much. My friends tell that not using the AC doesn't make a difference, but I'm not so sure.
I did notice a slight improvement in milage when I added the AIS to my 99 7.3 . Before changing the intake, I had the 6637 and and also the stock box. The AIS gave me another 1mpg. I also use the diesel kleen grey just to get my cetaine numbers up to make my baby happy since off road diesel is a no no Recently went up to Michigan - 350 miles up and averaged 19.5mpg - calculated. Returning with the 28' travel trailer I averaged about 13 - 14 but also had good cross and head winds.
I've got the same mods as Drew but I also have an Edge Platinum running on level 3 and Propane injected that I use on hwy hauls and I consistently get 18-19 hwy and get 15.5-16.5 mixed and that was over the winter. I think the exhaust and intake mods help improve the life of the engine and not really the mileage. I also use diesel kleen and while I haven't seen and mileage improvements from it I do feel it's help keep the injectors cleaner and the stock injectors are prone to failure, the explosive kind. I'm looking into having my injectors honed to smooth them out for better flow and to get rid of the all to famous burr.
Has anyone ever hooked up a Scangauge to see if the mods improve mpg?
I am going to buy one and test it. I can get a "loaner" cold air kit and since we have flat gorund in the middle of the prairie testing should be easy.
The Scangauge give real time mpg and the guys on the eco-forums swear by them.
I have a scangauge and it is great. What the scangauge is really good for is teaching you how to best operate your truck. I use it for the instantaineous reading but still hand calculate my tank averages. I made an excel spreadsheet that I keep a copy of in my gallery that has every fill up I have ever put in the truck along with the mods as I have done them. Honestly the truck has been extrodinary right out of the gate as far as economy goes.
here is what i did , i found a fellow on another forum and did what he did...Put a cover on the long bed, air to 70#, covered the air holes in the front of the grill where the hook holes stick out and the two on each side of the hood. still have plenty of air for the cooling no increase in temp. saw my mileage F250 08 6.4L increase from 15-16 mixed driving to 19.4. YOu casn say BS all you want. the proof is no tuners , keep my warrenty and best of all 38 gal tank x 3=114 more miles per tank. I'll post Sunday night after I tow my trailer 380 miles. it is a quick fix, low cost and no issues with expensive tuners that provide little to no mpg. Before you bash me try it.
I've been playing around with a few different types of fuel stations for my truck. For some reason 76 and Mobil my truck gets worse fuel mileage empty or pulling my trailer than I get with Chevron. Maybe Chevron uses different additives in their diesel but I notice a 3-4 Mpg difference.
'07 Ford F-350 12' Flatbed 3.73 LS 6.0L
18' Pressure Washing Trailer
I've been playing around with a few different types of fuel stations for my truck. For some reason 76 and Mobil my truck gets worse fuel mileage empty or pulling my trailer than I get with Chevron. Maybe Chevron uses different additives in their diesel but I notice a 3-4 Mpg difference.
'07 Ford F-350 12' Flatbed 3.73 LS 6.0L
18' Pressure Washing Trailer
That's interesting. I wonder if it has more to do with the pump nozzle at the stations you frequent. The tanks on our trucks are notoriously difficult to get filled to the brim (see Harpoon mod), and I know that some stations foam less than others. I believe it's the pump equipment. If you are not getting a consistent fill level your MPG results will vary. Just thinking out loud is all.
Bill
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My name is Bill and I approved this message.
Member So.Cal.Chapter
Nice group!
I never thought about that Bill. You could be very well right on that. I know my truck is a 40 gallon tank and only 1 time the fuel light came on and it took 35 gallons to fill it. The wife cringes though when I tell her it takes $160 to fill the truck vs. $60 for her Volvo lol.
I never thought about that Bill. You could be very well right on that. I know my truck is a 40 gallon tank and only 1 time the fuel light came on and it took 35 gallons to fill it. The wife cringes though when I tell her it takes $160 to fill the truck vs. $60 for her Volvo lol.
LOL, yea I hear ya on that.
To be consistent on figuring mileage we really need to fill until we see liquid in the tube, and with these trucks it's really hard to do that. And it can take 20 minutes of diddling around.
Bill
__________________
My name is Bill and I approved this message.
Member So.Cal.Chapter
Nice group!
I've been playing around with a few different types of fuel stations for my truck. For some reason 76 and Mobil my truck gets worse fuel mileage empty or pulling my trailer than I get with Chevron. Maybe Chevron uses different additives in their diesel but I notice a 3-4 Mpg difference.
'07 Ford F-350 12' Flatbed 3.73 LS 6.0L
18' Pressure Washing Trailer
I can generally concur with differing fuel quality. It's much easier to see when you're burning 100 gallons a day. I routinely get better mileage with Petro Truckstop's fuel, versus Travel Centers of America (TA). Pilots are about halfway in between. The reason why I buy TA fuel is the occasional discounts we get can be substantial. But it's something of a false economy, given that the mileage can be as much as 1 MPG less (20% or so). I haven't bought Flying J lately except in the Ford; it's quality seems to be middle-of-the-road as well. It's probably better that way: no out-of-range data to skew the figures, and make you scratch your head, going "WTF?"
It's a tad unfortunate that in my part of the state of TX (where I drive the Ford) that interstates are still routinely going 75-80 MPH; far too fast to get even "decent" mileage.
I get a solid 18-19 with my truck and have done most of the same mods and practices. Tires aired up, regularly rotated and balanced plus I have the Centrimatic balancers, synthetic oil, Fluidampr, Power elbow, etc, just look at my sig. I usually keep it in the 1500-1750 RPM range which means slow but steady acceleration, I coast up to stops and all that. I call these practices "Conservation of Inertia", not expending excess energy to get up to speed and not loosing it once moving. I am getting a tonneau for the bed(it was shipped yesterday, should have it soon) so we'll see what happens.
One other thing, I've been doing some testing with my GPS and have found that since I went up a size in tires(265/75-16 to 285/75-16) my speedometer is dead nuts on but my odometer is just over 2% low. When I hand calculate at 18.0 I get a corrected value of 18.4 so even a couple of percentage points gain will yield a benefit. Looking at it another way, if you use 1000 gallons a year at $5 a gallon(it's almost there here in New England) a 5% total gain from your mods is a $250 savings. You can figure your ROI from there...
I used to get in the 16-17 range before doing everything and now I run in the 18-19 range, a gain of around 10%+/-
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Recently went up to Michigan - 350 miles up and averaged 19.5mpg - calculated. Returning with the 28' travel trailer I averaged about 13 - 14 but also had good cross and head winds.
