7.3 @ 20-21 MPG?

[LCproject]

Hello, I just bought my first diesel. As I tend to buy things, I went to the biggest and best. 2002 F-250 Crew Cab 4x4 Long Bed with a topper, and the 7.3L Powesrtroke Turbo Diesel. I bought her in Ohio with 119,000 on her, drove back to Georgia after filling up. She went about 650-670 miles on 32 gallons, not completely sure because I drove straight through without a break and that's when I pulled over for a power nap. Unfortunately after I filled up, I reset the trip meter in my tired state. To my knowledge she was driving stock, is this normal? There is a Banks Six Gun hidden under the dash (the dealer didn't even mention it), and when I found it, it said error. So I'm sure it wasn't on while I was driving. I was amazed! I was driving about 70-75 MPH the entire time @2,000-2,200 RPM's. I am about to go to Ohio for Thanksgiving and just wondering, is this as good as it gets... Or will upgrading my intake and exhaust bump me to about 23 MPG? I was looking at the K&N system and a straight pipe. I don't know what pipe is best though, and would like a little input from more diesel experience. Also, would getting the Six Gun operational help? Any help would be awesome. I was driving a 2 door coupe before this that only got 16-18 MPG interstate LOL.

Thanks guys! (and girls)

[444-4D]

Fuel mileage is something you check until you get what you want then you quit checking. If I were you I would quit checking. Driving 70-75 MPH your truck will get around 16-17 MPG.

[LCproject]

Lol, is that what you would get 444? Wow, so I guess mine is doing better already... If you meant that I should be getting around that amount... I'm just asking if an intake and exhaust set would help me get more than my 20-21 I already get... Didn't mean to bring the sarcastic side out of people in here lol

[JimmyDee]

Best I ever got with mine was 19+. That was only once and my speed was less than 60 mph the entire time. The worst was about 11. I would say if you got what you claim, it may be a fluke. One thing about that engine I have found is that everything affects the mileage. You foot on the pedal, outside temp, speed, load, wind and there are probably 20 other things I can't think of right now. The only consistency with this engine is it inconsistency with mileage.
Jim

[LCproject]

wow, for my sake I hope it's not a fluke lol... It was kinda cold, quite a few semi's on the road, cruise control was broken so I had my foot in the same spot for hours lol... So I guess I have a long time ahead of me keeping track of inconsistent mileages lol. The topper most likely assisted to a degree I'm sure, it's an ugly topper, but now I'm afraid to take it off lol...

Thanks guys

Anyone else, just keep em comin...

[Lock]

I've had my truck since June, and I regularly get 19-21 hand calculated in mixed driving on my commute. But my truck is a 2wd 6 speed manual and I drive it to conserve fuel. Only mod at this point is a straight through 3.5" exhaust. I regularly can drive 600+ miles on a single tank of fuel which allows me to fill up once a week.
When I romp it stoplight to stoplight, or get on it more in traffic, then my mileage drops down to 18. I'm looking at a chip to help improve my fuel economy (at least after the novelty wears off and I'm done trying to race around).

[RIStroker2000]

no one has told you but stay away from a K&N filtrer set up... if your on the cheap you can make a 6637 filter assembly and a walker BTM muffler.. if you search here you will find alot of info on them

[SmokeyWren]

She went about 650-670 miles on 32 gallons.

That's over 20 MPG at over 70 MPH. I'm a skeptic.

Did you fill up though the foam until you could see liquid diesel at the cap? Both before and after that leg of the trip? Is your speedo calibrated so the tripmeter is accurate?

I bought mine new and have done all the normal things to maximize fuel mileage. Stock-size tires, 4x2 drivetrain, economy tune, free-flowing intake and exhaust, calibrated trip meter so I know the miles are accurate, grossing around 8,000 pounds when unloaded without a trailer. The most I have ever seen on an unloaded highway trip cruising at 73 MPH is a hair over 16 MPG, and that was only for two legs that were years apart over the last 11+ years and 192,000 miles. It usually gets 14 to 15 unloaded, and anywhere from 8.5 to 12 when towing - depending on speed, terrain, and wind.

So if you really are getting ove 20 MPG, then be extremely happy and don't hope for better than that.

On mine, the tune, exhaust and intake mods didn't improve MPG. Your mileage may vary.

[chuckster57]

Originally Posted by SmokeyWren

It usually gets 14 to 15 unloaded, and anywhere from 8.5 to 12 when towing - depending on speed, terrain, and wind.

I know I am running an old IDI..But I guess I need to be happy with my 14 MPG empty and 10.5 MPG pulling on the flats (E4OD, 215/85R-16, 4:10 LS)

[claw444]

the trip computer mpg is not always on the money. i suggest hand calculating. as suggest above be sure to fill tank to same point everytime.

in town i usually get 15.5mpg. on the highway at 70mph i usually get 17mpg. if i drive 55mph i get 19mpg on the highway. 55mph is way to boring and makes me sleepy. so i sacrifice 2mpg.

i have found diesel fuel quality greatly effects the fuel mileage. i get the best mpg on sunoco fuel. the stations pump filters play a huge part in fuel quality too. the extra penny or two is sometimes worth it for fuel.

[Victor]

I have regularly gotten 20mpg at 70mph in Colorado. As 444 mentioned, it drops quickly at higher speeds. I have never gotten 20mph at lower elevations (trips to Texas, California, etc.) so I know wind resistance plays a large part. My typical highway trip in Colorado is at 5000-7000 feet above sea level. Thin air helps a lot. I hand calculate and buy my fuel from Valero or Shell. Other brand fuels available locally burn noisy and produce less mpg.

My highway fuel economy dropped by at least 2mpg after I put a tall topper (camper shell) on the truck.

[fxdwgi]

I got 13-14mpg when it was stock, now get 17-18 @ 2000-2100 rpm.

It only took me about $6000 to get it there.....

[Rusty Hodnett]

I bought mine new in Nov, '00 and have watched MPG since day one. Mine is 6 spd, 2WD, LWB with a Glasstite cap. The truck is bone stock except for a Ford AIS air filter and Kim Lux injectors I installed in '01 soon after I bought the truck. I don't have a computer so when I want an accurate no. I do as Smokey said and fill up past the foam until I see liquid almost at the spout. I have not had my speedometer calibrated, so I can't certify my numbers. I routinely achieve 19+ MPG at 70+ MPH. I found that by cruising at 2000 RPM (approx. 67-68 mph) my mileage goes up to 20+ with a recent tank at 21.1. I went 750 miles before filling up...95% hiway. The worst I have ever gotten not towing was 16+ around town. I haven't towed enough to report, but I did tow a 5000# boat from Eastern Maryland to Columbia, SC (573 miles) and got around 12.5. As a point of interest, I can usually add 3.5-4 gallons after the automatic fuel pump stops...takes another 5 minutes or so for that last few gallons.
I'm gonna keep it until it dies or I die...I'll probably go first.

[mwe-maxxowner]

I would say check it a few times before you count on that being accurate. You can easily add 3-5 gallons more after it clicks off the first time on most pumps. That makes it easy to be inconsistent in the amount of fuel you put in. You could milk the last 5 gallons in on one fillup, drive till empty, then stop at first click next time, and have an outstanding mileage figure-but it won't be accurate. Best way is to keep up with it over several thousand miles on a tablet in the console. Over 1500-2000+ miles, a couple gallons difference won't affect your numbers as much. My problem is I can't stand to drive for mileage for more than one tank, and usually not even a whole tank lol. This thing's just so much fun to drive when tuned

I can get 18-19 around town out of the truck in my sig, and can milk 20 if I try really, really hard. But that's no fun. I'd say highway, unloaded, it may get 22 if I keep rpms at or below 2,000, but I don't know. It's always loaded on highway trips, getting about 12 with the camper. Otherwise we take the 35+mpg 4cyl car. 21 highway is very possible, but at 75 mph, I highly doubt it. At 70, maybe.

[wheelhopper]

The best I ever got was about 19.5mpg on a trip. I used to regularly get 600 miles per tank. I have not seen that in long time. Not sure if it was the switch from stock tires to 285/75/16s or the ULSD, or combo of both. Now I typically get 500 miles per tank. I sure would like to get back to 600 per tank.