Many reported 7.3 MPG and HP numbers have dipped into the black arts of tuners and tall tales on forum sites.
You know the ones--"I got 25 MPG while towing a 20,000 pound trailer uphill with a 30MPH headwind! Believe it!"
Uh, maybe. But yes, you can get better 7.3 MPG. But increasing diesel fuel economy isn't as simple as slapping on tuners and turning the knob to "tow".
Let's look at the numbers...
Compared to a standard gasoline engine, a Ford F250 equipped with a 7.3 diesel engine is generally more fuel-efficient—i.e. you'll get better 7.3 Powerstroke MPG than say an F250 equipped with a V10 gasoline engine.
Since diesel fuel stores roughly up to 15% more energy than gasoline, your 7.3 Powerstroke diesel will, properly driven, get around 30% better MPG than that F250 V10.
But, since most places I looked, including fueleconomy.gov and Nada guides state that "EPA Fuel Economy MPG estimates not available" for the 7.3 Powerstroke, I had to do some digging to find averages that I'd consider reliable.
Since most of the 7.3 MPG information out there is second-hand here-say from forum posts anyway, I used number averages from a site called fuelly.com. Using their tools I got a lump sum average from tens if not hundreds of actual 7.3 diesel owners, stating their own experience with miles per gallon fuel efficiency.
Here's what I found out about 7.3 Ford F250 diesel fuel mileage in particular...
Fuelly.com states that "Based on data from 92 vehicles, 5,396 fuel-ups and 1,822,710 miles of driving, the 1999 Ford F-250 Super Duty gets a combined Avg MPG of 14.82..."
Fuelly.com states that "Based on data from 92 vehicles, 3,981 fuel-ups and 1,223,722 miles of driving, the 2000 Ford F-250 Super Duty gets a combined Avg MPG of 14.07..."
Fuelly.com states that "Based on data from 66 vehicles, 3,750 fuel-ups and 1,010,890 miles of driving, the 2001 Ford F-250 Super Duty gets a combined Avg MPG of 13.62..."
Fuelly.com states that "Based on data from 68 vehicles, 5,084 fuel-ups and 1,838,593 miles of driving, the 2002 Ford F-250 Super Duty gets a combined Avg MPG of 13.38..."
Fuelly.com states that "Based on data from 17 vehicles, 1,362 fuel-ups and 395,452 miles of driving, the 2003 Ford F-350 Super Duty gets a combined Avg MPG of 12.79..." and for the 250 "Based on data from 31 vehicles, 1,140 fuel-ups and 332,545 miles of driving, the 2003 Ford F-250 Super Duty gets a combined Avg MPG of 12.59..."
Fuelly.com states that **Based on data from 163 vehicles, 6,652 fuel-ups and 2,898,262 miles of driving, all 7.3 Excursions got an Avg MPG of 13.38...
** I hand calculated these numbers from Fuelly.com's reported numbers for each model year.
97 Ford F-250 Super Duties provided Fuelly.com with 1.2 million miles of real world fuel economy & MPG data. Over the entire span of their production range, 1999-2010, And Ford V10 gas engines produced a reported average MPG of between 8.1 and 11.7 MPG.
Which holds true with our data of 7.3 Diesel MPG, at roughly 13-14 MPG, averaging around 25-30% better than a similarly powered gas engine.
But hold on—there's a few things about these 7.3 MPG stats:
First, all theoretical statistics on MPG are complete BS—only your own field data is reliable for you. Because the way you drive, the quality of the diesel fuel you put in your vehicle, and how well you maintain your engine are what will truly determine your own results.
That being said, a few things to keep in mind:
After surfing more 7.3 fuel consumption data and stories than is healthy, the personally reported fuel efficiency numbers for most 7.3 Powerstroke diesels seem to fall somewhere in the 13 City/ 18 Highway range.
If you surf the Internet for 7.3 Powerstroke MPG, you're going to come across forum posts that reference "hand-calculated" 7.3 Powerstroke Fuel mileage.
Simply put, and at the risk of being too comprehensive, here's what hand-calculated MPG means and how it's done:
I know that was too basic, but someone was going to ask me, so ... there it is.
Way back in 2007-2008, the average US price for diesel fuel skyrocketed. To make matters worse, my wife and I were living in San Jose, CA. at the time.
Now, it's a gross understatement to say that California politicians love their gas taxes. A fact that makes a California diesel fill up one of the most expensive in the nation. Doesn't matter if gas prices are up or down, sunny beaches, movie stars, and "free" stuff for everyone apparently costs money.
And since they can't make the electric car drivers pay for it, that leaves you and I and our nasty diesel trucks to foot the bill. Ah, a rant for another day...
Back to 2007-2008 diesel fuel prices...
Bay Area diesel pump prices were constantly "topping-off" at over the $5 per gallon mark. And my 2002 Ford F350's 7.3 diesel mpg being what it was... At best my F350's fuel economy was 15-16 mpg highway and somewhere below 12 mpg in Silicon Valley's "pause and putter" traffic.
Let's just say that driving my truck for anything beyond absolute necessity was painful on the pocketbook.
So when my wife casually asked if I'd run to the store and get bread for our kids' lunch sandwiches the next day, I froze up. Then I quickly did some tricky math in my head, At 10 miles per gallon, for almost 20 miles round trip, that's...
Now, I'm no "Ford genius engineer", but by my calculations that single loaf of bread was going to cost $13 by the time I got it back to the house.
What happened, you ask?
Well, I mumbled something to my wife about "this not being Russia and bread shouldn't cost … blah blah." Then I diligently went and got the bread, of course. Not the point.
But since I was certainly not selling my diesel to buy a Tesla — it won't tow a trailer — something had to be done. That's when my interest in increasing my 7.3 Powerstroke's MPG started.
I'm sure this is going to get me heckled and burned at the stake, however ... the quickest way to get a free boost in your 7.3 MPG is right at the bottom of your right leg.
Because, if you're like me you love your 7.3 Powerstroke engine's POWER! And let's be honest, stomping your right foot down on that long thin pedal and listening to your turbo spin up and the growl of your 7.3 diesel and then feeling it muscle its way down the road... Well, that's part of the joy of 7.3 Ford ownership, isn't it?
Well, yes it is, but it's also one of the biggest things that robs your 7.3 of fuel mileage. So, if you want better 7.3 MPG, do yourself a favor and ease back on the accelerator. I know it's not fun, but it's certainly effective, not to mention a cheap upgrade.
I'm not saying you need to drive 55—that would kill me too—but gradual acceleration, keeping your 7.3 at or below 65 on the highway, and watching your RPMs going uphill will start you in the right fuel efficiency direction.
I'd think by now that it goes without saying that your 7.3's HEUI activated fuel delivery system depends heavily on clean fresh oil. Not only to feed your high pressure oil pump and deliver efficient pressure to actuate your diesel fuel injectors, but also to reduce friction in all the major moving components inside your engine.
And less friction from clean, high-grade oil means your engine has to work less to deliver power and torque to the road. And what does all that efficiency and friction reduction equal? That's right, better 7.3 MPG.
Do your fuel 7.3 MPG averages and your Powerstroke's engine's fuel efficiency a big favor and religiously and regularly change your 7.3 oil with high-grade diesel engine lubrication.
Weight reduction—works with every truck, every time. If you don't have to haul it, don't. Because driving around with a needlessly overloaded pickup bed will rob your 7.3 Powerstroke's MPG ... period.
The 7.3 was and is a Ford engineering marvel, obtaining legendary status both at the time of its production and today. Especially after over 15 years of 7.3 Powerstrokes racking up hundreds of thousands of miles each.
And yet ... there's one area that there's a big room for engine design improvement. And that's air flow. More specifically, exhaust flow.
Simply put, a restricted exhaust robs engine power and thus efficiency. And at the risk of launching into an Eddie Murphy analogy ... we've got to make sure we don't fall for the "banana in the tailpipe" trick. I.E. exhaust restriction.
Upgrading your 7.3 exhaust tube to a 4" has been reported to improve 7.3 fuel efficiency from 1-1.5 MPG.
Interestingly however, I've yet to come across a forum thread discussing the ROI of 7.3 fuel efficiency upgrades. So we're going to tackle that here.
Because, hey, if we're so concerned with 7.3 fuel efficiency, shouldn't we figure out if getting better diesel mileage will actually net save us money?
A 4" exhaust upgrade can cost you anywhere from $300 to $500 to $1000, depending on whether you DIY it or pay a shop, or horrors, your local Ford Dealer.
And let's be conservative and say we get a 1 MPG boost, pushing us to 15 MPG average. At $3.5/gallon for diesel we get $3.5/15MPG yielding a diesel fuel operating cost of roughly $0.23/driven mile.
Dividing an average cost of $500 for an exhaust upgrade by our savings of $0.23 for our one mile increase in 7.3 MPG—500/.23—we'll get our invested money back from our exhaust upgrade in 2174 miles, right?
You see, we're only going to get that $0.23, 1 MPG efficiency increase every 15 miles. So that means we have to drive 15 miles, 2174 times—15*2174—in order to recoup the $500 that our exhaust cost.
And that number is 32,610 miles! Ouch... So just keep that number in mind when you're "investing" in MPG upgrades. Because the best upgrade you may find is a $3,000 commuter that gets 30MPG.
Some of you may be too young to remember this, but back in the day—1970-80s ish—pickup manufacturers dealt with the gas crisis and MPG issue by shipping their trucks with these tiny little diminutive tires. I'm not talking the ones they ship stock today that just make your truck look meh—bland. I'm talking about big-truck-on-rollerskates tiny.
And guess what? They got better MPG out of their Ford F250s. They weren't pretty, but they got the job done. (which at the time happened to be satisfying EPA regulations)
So the next time you have that impulse to beef up your tire size, not to mention lift your 7.3 diesel suspension up into the bleachers... Going from 33s to 35s or 37s can rob you of 1-3 MPG.
Hypocrite alert! - I'm as guilty of anyone of lifting and putting bigger tires on my rig. Because let's face it—it looks cool and that's part of owning a big truck, isn't it?
And to further complicate things, there's anecdotal information—Ford Truck Forums—that suggest even different brands and treads of tires in the same size will effect 7.3 MPG. Even reports of up to 2 MPG increases going from one brand to another.
In addition, aggressive tread tires rarely outperform the miles per gallon of road/highway radials.
So if you're looking for maximum 7.3 MPG, skip the big aggressive tires.
And speaking of tires, the next thing you'll want to check is your tire pressure. I'm not talking once a year either. I try to check my 7.3 diesel's tire pressure once a week and always before I go on a long trip.
Aside from the obvious safety implications and the reduced wear and tear on your tires and rims, the correct tire pressure can save you 1-2 MPG in fuel efficiency and it's as cheap as the 15 minutes it takes to check it and fill them up to the correct pressure.
I like to write as comprehensive a post as I can, so I'm sorry if this video insults you. But I've come across several people who still don't know how to properly inflate their tires ... both loaded and unloaded.
In short, there are two places to look to find the correct tire pressure for your Ford F250 7.3 Powerstroke diesel: The sticker on the inside of the driver's side door jamb and right on the sidewalls of the tires themselves.
Get a good gauge and check them and fill or bleed them off until they're all the same and at the correct pressure for the load you're carrying.
One of the easiest ways to give your engine a little MPG fuel efficiency boost is to replace your 7.3 Powerstroke cold air intake with a new aftermarket one.
But I don't want to go that route right away. Because one of the simplest things you can do is regularly change your 7.3's stock air filter element. Notice I didn't say "upgrade" I said change it. Because rather than spending a few hundred on a new air intake, why not just get in the good habit of maintaining what you've got.
I'll admit it's not "cool" or "sexy" but regular maintenance and fresh parts to replace worn ones is pretty easy to do, not to mention inexpensive.
So about every third 7.3 oil change, 15,000 miles in my case, I swap out my air filter with a new one. And depending on the type of driving I've done, I can tell it needs it.
There's a FRAM Air filter out there that will do just fine as long as you keep up on the maintenance intervals, but this Motorcraft FA1750 Air Filter on Amazon will satisfy you, "OEM or Death" 7.3 Powerstroke owners.
I like this S&B 75-5062 cold air intake for 1998-2003 Ford Powerstroke 7.3. Partly, because I can view the filter element through the plexi-window, and I like that better than having an exposed filter under my hood with all the recirculating air. But also because it fits so well and looks more natural under the hood than an exposed cone aftermarket filter. And believe me, in a California smog inspection, the appearance of "stock" is important.
But more importantly, with this air filter intake upgrade, you'll probably experience a noticeable sound and felt power increase. You'll actually hear your wastegate opening with this intake as well as your turbo spinning up and whining. This is a great upgrade to do in combination with an upgraded exhaust (mentioned above), because the stock air intake with rob your air-hungry 7.3 of needed air.
Careful though, because if you live in Cali, the California Air Resources Board (C.A.R.B) is constantly changing the rules on aftermarket air intakes and unless you get that C.A.R.B. sticker to prove that this is approved... Let's just say that I've had to call the air intake manufacturer to get a replacement sticker mailed to me.
This particular model is a 75-5062 and when I last checked this list of approved aftermarket parts for CA, it was on the list.
I've written enough detailed information on this site about the 7.3 HPOP and how important it is, what it does, and how to remove, repair, and replace your HPOP, and about HPOP leaks, that it would be redundant to repeat it here.
Suffice to say, a healthy HPOP that delivers adequate pressure to actuate your injectors effectively ... is a 7.3 MPG and HP necessity.
Ice-cold Air Conditioning... Fords are famous for it. And your 7.3 Powerstroke diesel is no exception. It doesn't take a rocket scientist to feel the power loss and experience the fuel economy robbing effects of your Powerstroke's AC working overtime.
If you don't absolutely need it, leave it off. Your MPG will thank you.
Now, before you go crying foul, and "we're not Navy SEALs, I wanna be comfortable in my truck". I lived in Phoenix for a time and in Sacramento during a summer that you'd swear you were in Phoenix and I rarely used my AC. Heat is relative and I said "pretty" easy ways to improve MPG and HP, not uber-comfortable.
You were hoping I'd get to this, weren't you? I'm going to write a detailed article about 7.3 Powerstroke tuners and chips. Because there's ample evidence that the right tune can increase your MPG and HP dramatically.
How dramatically is up for debate. Because going from a factory average of from 12.5 to 14.5 or 15 MPG to close to 20 MPG in your 7.3 has got to come with some ... gotchas. And I'm still not sure if I believe all the forum-jockeys claiming they get over 22MPG while towing a house in a headwind.
But hey, that's just me.
So, there you have it—some pretty easy ways to increase your 7.3 MPG. Aside from the exhaust upgrade, most of them can be done cheaply and quickly.
But let's not forget...
You probably bought a truck to haul, tow, mud, hunt, fish, camp, or just have fun with. So buying an F250 7.3 diesel to get better MPG...? Really?
My dad used to have a saying whenever he'd drive his truck by a diminutive fuel economy car—"pregnant roller skate" he'd call them. Not P.C. by any means, but then again, he wasn't.
But what he didn't mention was that ... PR we'll call it got 30+ MPG. His own PR was a 1979 Honda Accord hatchback that I drove through HS and college to almost 300,000 miles before selling it. I had 2 more Hondas, a '94 and a '96 Accord, and they both got 40+ MPG!
My current version of the PR is a 2015 Honda Fit that gets, wait for it, 39 MPG. And that's no forum exaggeration. And whenever we don't need the trusty Ford Powerstroke 7.3 diesel's towing, 4x4, or cool factor, we take the Honda and effectively just about triple our fuel economy!
Think about that... Possibly the best 7.3 MPG "upgrade" could be an economy car so you can park your 7.3. Horrors...
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