Hi guys, I have a 2002 F250 7.3L, DIY intake, 4x4, 3.73ratio, riding on 285/75/r16 Firestone destination A/Ts. Being Form central Illinois we have a great road grid, but with that comes stop,go,stop,go every mile kind of driving with a few 25-75 mile hiway trips. Here are my questions: what chip will do best in this scenario, if I put 17x9 rims and bfgoodrich km2s on will it hurt mpgs bad, and will a boost annhailer do anything else other than keep truck form throwing code. thanks for suggestions and comments
Max

 

Boost annihilator only fools the PCM so no codes. The bigger the tires, the worse the MPG's that's just the facts. It's a function of unsprung weight, friction, and changing the final drive. The best thing you can do to improve mileage is keep the RPM's under 2,000. I can never do that. These trucks are not built for mileage, it's a huge flying brick.

 

This is the Man. I asked him to be a Mileage Moderator over here too, but to no avail:

Improving MPG - PowerStrokeNation : Ford Powerstroke Diesel Forum

What Doesn’t Work - PowerStrokeNation : Ford Powerstroke Diesel Forum

Tire Size and MPG - PowerStrokeNation : Ford Powerstroke Diesel Forum

Check 'Em Again Boys - PowerStrokeNation : Ford Powerstroke Diesel Forum

Sticky: What Kind Of Mileage… - PowerStrokeNation : Ford Powerstroke Diesel Forum

Maybe A New Test - PowerStrokeNation : Ford Powerstroke Diesel Forum

 

My short advice and it is worth all of $0.02 is keep it below 2000rpm....a little less if possible assuming you have 3.73s......the 7.3 gets a little thursty above that.

 

X2 on the bigger tires. Just bought a '02 F250 6 speed. Hand 235 65 20's on it. Was getting about 15 - 16 MPG switched back to stock size, i believe 285 75 16. and mileage jumped to 19MPG.

 

Watch out for odometer inaccuracy when you bounce the sizes. A bigger tire shows fewer miles traveled on the odo.

 

This is one of the biggest things I've come across with my truck that most guys don't think about.

I'm not on the wagon with the big tire thing though... With my tires ( calibrated) I see most mileage that guys with stock tires see. Average 13-14 mpg with 85% stop and go city driving with a heavy right foot. Highway I don't get on much anymore to talk about that but last I checked I was at 16.25 average.

One of the brothers here has a signature I can't forget. It reads... For economy place an egg under pedal... For performance remove egg
It doesn't get anymore honest then that

 

I have done a lot of research on MPG. I have compiled the best tips and tricks to improve MPG. Some things I think are silly suggestions, like "Get smaller tires" or "get a car". Sure, you get better MPG, but what if you want/need bigger tires? Most people want suggestions on how to increase MPG with their current setup, because their current set up is usually the set up they want. For example. My truck is lifted 3", on 35" Hankook Mud Terrain tires with a light bar on the roof and an grille guard on the nose. Just SCREAMS aerodynamics doesn't it. I broke my record MPG just a few weeks ago. 20mpg. And before someone says "lie-o-meter" or I didnt fill up to the brim.. to that I say nay nay. I track every fill up manually, and both the preceding and succeeding fillups were perfectly within normal limits, indicating no anomalies on the fill up. I dont commonly get 20mpg, but I took a road trip. Normally I get 16-18mpg per tank.

So I bet by this time everyone wants to know what the secret is. Well, its quite simple. Maintenance. Follow a strict maintenance routine and that is the single best thing you can do to improve MPG. I use an app called aCar on Android, but the app Gas Cubby on iOS is very similar. With these apps I track every fill up, set maintenance intervals, and get reminders on my phone. I am strict about maintenance.

There are other things you can do to improve MPG obviously, but everyone always has different results, based on where youre trucks weakest link is. For me, mine was boost leaks. I got some intake plenum inserts from Riffraff and it boosted me 2-4mpg by sealing up the leaks I didnt know I had. I also throw in a couple gulps (thats a scientific term) of Diesel Kleen on every tank for good measure. I dont claim to have all of the MPG answers, but I know that what ever I am doing, appears to be working.

Things I will recommend,

- Regular Maintenance (quality components; oil, air filters, etc...)
- Service and Repair of malfunctioning components (EBPS is a prime example)
- Boost leaks (Get a boost leak tester. I have a video on this)
- Fuel additives (Up to you, and choose your flavor. But do some research. Little evidence to support this, some evidence shows some brands do more harm than good)
- Tuning (Can improve MPG, but you will likely never get your investment back
- Driving Style (This is the biggest thing you can do honestly.)

Beyond that, the obvious things like tires aerodynamics etc... If you truly dont care about big tires, lift etc then ditch them. They do effect lift. But for people who want that stuff, keep it. No sense in having a vehicle you dont enjoy driving!

 

Yeah I thought about that. Just found one of those online tire calculators. from the 275-65-20 to the 265-75-16 It's right at 5 mph difference. I don't think that would make a 4 mpg difference in 300 miles.
I mainly changed back to stock because the 20's were rubbing on my springs while turning, I need good m+s tires and the price difference was huge. I was just surprised that there was that big of a difference in mileage and ride quality.

 

Not sure it'll be much help but I'm from central Illinois too. I've got a 2000 F350 cclb 4x4 with 3.73. I have an edge evolution on mine with 285/75/16 BFG all terrain, mainly city I can get 13-15

 

I lost almost 2 mpg going from 285-75-16 to 315-75-16 with a corrected spedo. Next set of tires I may go back down a tire size and lower my lift for mileage, what fun would that be! Bigger tires or bigger lift than stock never gets good mileage on a 8000lb truck!

 

I'm on that page.

Mysteries of tire size revealed!

The first number is in mm width.
The second number is percent of the first number, representing height from the rim (mm again).
The third number is the inner diameter, or rim size - in inches.
What the hell kind of system blends metric, percent, and imperial measurements all in one formula?

Anyway, a 285-75-16 is 285 mm across, with a 214 mm sidewall, and a 16" center.
From center to the tread is 214 mm (8.4") + 8" (half of 16"), or 16.4"
16.4" times 2 is the diameter of the tire, which equals 32.8 - or 33 is close enough. A stock tire is about 31.5", and half of that is 15.75" (center to tire tread).

All this to say the 285-75-16 is {drumroll} 3/4 inch taller than stock. {insert trumpet fanfare here}

 

When I drive 69 mph, I get 13.8-ish. When I drive more like 55-60 mph, I get 17-18. I have taken a ski trip several times on back roads where you rarely get over 60 - and that's when I get exceptional mileage. In-town mileage flat stinks - 12-13. Two things kill mileage - starting and stopping these beasts, and trying to drive them over 70.

 

Interesting tidbit happened to me a few weeks back. I lost my tuner - not the fault of the hardware, another issue was at play. I have injectors that are nothing like stock, but my PCM has stock tuning. I had to drive 400 miles on stock tuning with AC 160/100 single shots. Stinky got just over 18 MPG.

What this tells me is that while many may find a marginal improvement in MPG with tuning alone, I am convinced more than ever that tuning (differently than stock) is a tiny aspect of MPG on this engine and truck. While the stock tuning may have a little room for improvement, it has a football stadium of space for being worse.

The condition of the truck and your right foot... look there first.

 

OK, Tugly since you broached the topic of injectors and tuning in this mpg thread. Do you think that the new Alliant AC Code 160 cc injectors with stock nozzles and great tuning could get better mpg than new Alliant stock AD Code 135 cc injectors with stock nozzles and great tuning. Both driven the same and conservatively.

I found this online. Hopefully it is accurate:

Stock Injectors: CC Flow & Nozzle Size
90 cc Stock Nozzle 225 to 230 AA Code / Single Shot ('94 to '97, Non-California)
130 cc Stock Nozzle 260 to 295 AB Code / Split Shot ('96 to '97, California)
135 cc Stock Nozzle 275 to 315 AD, AE & AF Code / Split Shot (99 and later - AE and AF are "Long Lead" Injectors used to help eliminate "Cackle")
160 cc Stock Nozzle 325 to 345 AC Code / Single Shot (T444E HT engines only)