How many of you are actually hand calculating??? What has been your comparisons to the overhead if so????

 

Are you kidding me? My overhead Lie-o-Meter is always at least 2.5-4 MPG off from hand calculation. Always hand calculate. I put a duct tape on my overhead Lie-o-Meter.

 

Just to update my previous post,
I have been running hand calcs on every tank for the past couple months (haven't had the truck long) and using various settings on my Bully Dog Triple Dog programmer. Around town (rural/city) I am averaging between 16.2 and 17.7 on the programmer, with the 17.7 coming on the "No Extra Power" (stock) power setting. Before installing the programmer I got 18.4 mpg-highway on one trip, but I'm not sure it was an accurate reading, since it was my first tank full.

I have been told that many people are seeing their best mileage with the Bully Dog TD when set on the highest power setting and driving mildly. I have not found that to be the case. My mileage has dropped incrementally with each increase in power setting while keeping the same driving style and routine (around town driving). Still, My mileage has decreased only about 1.5mpg from stock to Extreme on the power setting, while the power has had a huge increase. I look forward to my first long trip, so I can do the same trials with highway mileage.

My overhead reads between 19 and 22 on all but the "Extreme - Crazy Larry" setting. On Crazy Larry, the programmer seems to really fool the meter and it reads right around 27-28mpg while actually getting about 16.2 or so.

On the other hand, my Dad's '01 2500 gets 21-22 hand calculated (summertime fuel, stock truck, no programmer) and within a few tenths of that on the overhead meter. He gets around 17-18 on winter fuel by the meter, but I don't think he does hand calcs anymore, since his meter has been so close.

All I can say for sure, is that with a programmer, your overhead meter will likely read high by about 3-4mpg at least, judging from my experience and what I have read on the forum.

 

I have always used hand calcs. A family member swears that the computer on his Chevrolet is accurate. He says that the manufacturer would not put an unaccurate setup in these trucks. Anyone else agree?

 

Absolutely agree, I get 22-23mpg on the O/H in stop-and-go traffic all the time...Don't even bother to Hand-calc. :Sarcasm

 

You are doing good by hand calculating keep at it. Disown that family member because obviously he/she does not know any better. The Lie-o-Meter is just a "guestimate" of what it think the amount of fuel used based on various parameters and sensors. The computer guessing because unless there is a fuel flow meter on the fuel line from the tank, the computer does not really know how much fuel is siphoned from the tank given the miles driven. Noff said!

 

I've seen 27mpg on my overhead.

 

I always have to chime in on these mileage threads

Dont feel bad - everyone that claims they get more than 20 miles per gallon gave you false hope...sorry

Untill I fill up a persons 3rd gen truck with 34 gallons of fuel and I ride with the same person without stopping for 700+ miles - I will never believe them that a 3rd gen gets over 20 miles per gallon - NEVER. So which one of you guys are going to come and take me on a ride

 

I get a pretty consistent 18 MPG hand calculated empty on the freeway with my Edge set to 1. It gets even better mileage @ 60, but I don't do a lot of that around here.

But... Short trips, #1 or winter blend diesel, head winds, heavy foot... will bring that down pretty quick.

Also I've noticed if the air filter is really dirty that effects my mileage too (those filter minders aren't worth much in my opinion).

 

Do any of you have the fuel tank vent mod?

 

My mileage was running between 19.5 - 20.5 until I recently changed my tires. The new tires are 1" taller and 1.5" wider and they took about 1.5 - 2 mpg away. I did recalibrate the speedo too.

As far as the lie o meter, mine is off 2.5 - 5 mpg consistently. The thing that really pisses me off is that the ECM stores accurate data about economy. At around 90K miles I had a service manager hook up the starscan tool to my truck and the lifetime mileage in the ecm was very close to my hand calculated life time average, it was only a few tenths UNDER actual.

 

I get 13-15 city, but highway runs 17-18.5. If I had 265s on the truck I'd bet good money my truck would clock 20mpg hand calc'd, best tank before airbox and exhaust mods was 19.4. But the 285s just can't do it. Maybe with a supreme tailwind, downhill all the way but so far 18.5 is tops with 285s.

My lie-o-meter says 22.3 and regularly runs 2-4 off.

 

Hello? He bought a Bowtie! Wouldn't surprise me he bought "O's" promises too.

Dan, come on. It all has to do with the driver and the conditions he drives in. My best distance on one tank was 725 miles. My best milage was on a "Sunday" drive from Yreka to the coast and back to 5, I think I got just over 22. Of course, everything is hand calc. The driving conditions: comfortable 45-55 MPH, no heavy foot, no 5th wheel, 1st wife next to me, easy mountain driving, no traffic, ...

I think if I repeat the same, I'll get the same. BUT, that is not normal driving conditions, at least for me. Mostly, I get 17.5 - 18.5, commuting 75 miles/day, mostly freeway at 70-75 or so. My last tank, drove from Suisun up to Reno for the weekend driving usually not more than 65 (till hitting Nevada), the lieometer said I didn't do too bad going up and over to Reno, but coming back, the lieometer put me in Sac at 31. By the time I finished the tank after 3 more days of commuting, the lieometer was down to 29.9, distance was 639.1 miles, took on 31.593 gallons (till I can see the fuel in the tank spout). Well, that computes to 20.22 and change. Again, not normal driving for me.

I think we get great milage driving over the hill and back normally anyway as the worst uphill milage is about 8 vs the normal downhill milage of 50-99+. lol
Back to my morning brew...

 

Exactly!

20mpg is completely possible

20mpg on a regular daily basis for all conditions - not likely

 

100% agree.

I pull 16 mpg tank averages all the time. The overhead was gracious when I ran 265-17 rubber. Now I have 315-17's and with the speedo still off by 4-5 mph the overhead is pretty much spot on. If I reset it at evey tank it's only off by a few tenths.

I notice the best fuel mileage when the filter is fresh and I run XPD additive.

While I can still force out 17 combined, 16 flat is more realistic. 20 on the highway is still no problem. 125k on the ODO.