In case you all haven't noticed there is a considerable, :wtf1: massive variation of MPG postings on the DP site. Some guys post very low MPG's, others very high MPG's, albeit with the same basic trucks in many cases. So the guys on the short end of the stick feel like their trucks are screwing them while the guys on the long end are "happy as a pig in slop"! :D

So I am proposing a "DP Standard for computing MPG's"! This way we can compare "apples to apples" when posting our MPG's. No pride of authorship on this so if we need to tweak this fine. Main goal here is consistency. ;)

Here is a proposed method for computing DP MPG's:

- All mpg calculations must be DIC-less, that is they must be computed by hand;

- For those whose odometers haven't been corrected for larger diameter tires(they don't make em any smaller:o: ), you need to calibrate your true odometer readings. For example, take your truck onto the interstate and use the mile markers to verify your true odometer reading. Once you know your computation formula use that to compute MPG's;

- All fill-ups should be on level surfaces, minimal inclines/declines or side-to-side fluctuations, etc.;

- Depending upon where you fill-up nozzles can dispense diesel fuel at varying rates. Truck stop pumps dispense at very high volumes whereas most gas stations pump at lower rates. Coupled with diesel foaming the nozzles will click off at differing points. You might squeeze another 2 gallons out of a gas station pump over a truck stop pump if you stop at the first click. :o: We're never going to get exact numbers due to this. So for our purposes tanks will be considered full when the fill tube foams up and shuts off 3 times at minimal nozzle dispensing. Do not fill to the top of the fill tube, make sure the fuel drops back out of sight in the fill tube;

- Then divide miles driven by gallons dispensed for actual MPG's. :ro)

Following a set, prescribed method for computing MPG's maybe we can narrow the consistency gap on MPG posting! :rolleyes: Call it what we like, "DP MPG Computation Method" rolls off my tongue. :cool:

FWIW, following the method above I achieved the following MPG's this weekend: averaged 60mph, 102 mostly highway miles, used 6.18 gallons = 16.5mpg; steady 70mph, 122 interstate miles, used 6.60 gallons = 18.48mpg. Each tank filled til the filler tube foamed down 3 times.

Other thoughts? JJ :)

You gotta lotta spare time to think this shiznit up.. lol

Looks that way, at least this morning. :rolleyes: If you've read many of the posts on MPG issues you would understand why I proposed a consistent method for computing MPG's. There are guys out there ready to get rid of their trucks because they are only getting 13mpg's while others are posting 18-19mpg. :o:

I suspect some of these high posters may stop filling up at the first click, while others take the time to fill the tank completely. :exactly: The proposed MPG computation method puts posters on as level a playing field possible. So what's your DP MPG? :D

I always try to fill it up untill I see actuall fuel. Or when I am worried about milage anyway, that way I know I'm reading the same level. It takes for ever though.....

JJ, I see your thought.... How about this ...Most of us will have the truck for 5k miles, right? Write down your OD mileage, engine hours and record every fill-up, even the 1/2 fillers. Now, drive your truck for 5k miles and do the math. That will give each of us a pretty darn good Idea of how we drive and what MPG we avg.

Does anyone know exactly what a gallon of diesel fuel weighs? I propose that we weigh our trucks immediately before and after we fuel up. That way we would know exactly how much fuel we put in. Of course, someone will add their fuel additive before the second weigh-in and screw-up our whole system again! Oh no! Wait - winter and summer blended fuels may weigh differently. So, from March 1st. each year through September 1st. each year you can only post your MPG's if you've run summer fuel. From September 1st. - April 30th. you can only post if running winter fuels. No wait! Some areas of the country may not change fuels during the year. Ok - Lets divide the country into 4 quadrants. The Northest quadrant can only.............awwwww forget it!!

Just funn'in ya JJ - you have way too much time on your hands :)

JJ, I think one of the biggest factors is how we drive. I know im turning 35's and all with more wind drag and after the reflash I was moving all my stuff from Kansas to Colorado in a 16 ft trailer, first tow by the way with my truck, it pulled great plenty of power even on lev 1, but I was seeing 8 MPG, not good. So after I dropped the trailer off I drove my normal speed around 70 or so, I was seeing 12MPG on the DIC, I was like sh** the reflash screwed my milage, so on my way back from Wyoming the other day, I turned the juice down from 3 to 1, low boost on 1, accelerated slowly, drove home around 63 MPH, no big hurry, the DIC read 16-16.5 mpg which is a huge difference. The one thing that Ive noticed is if you can keep your EGT no hotter than 750 your milage is good, anything hotter my mpg goes down the crapper!

Right on Burner, if we are going to the trouble of making a standard, let's make it right. I would say at least 10 fill-ups, preferably a mix of driving (city/highway, winter/summer, etc.). Don't worry about how full the tank is, the average will take care of that. Just write the mileage on each fuel receipt and at the end add everything up and divide. Simple.

Burner, personally I figure my mpg's on every fill-up. If the mpg's drop dramatically and there is no logical reason (towing, lots of city traffic, etc.) it may be an indication of other problems that need to be addressed. Waiting for 5k, while it would give you an overall average, wouldn't decipher between highway mpg's and city mpg's. :o:

Those that post/watch their mpg's are likely those that check them on a regular basis. The purpose of this post is to use a standardized method to doing it on the DP. This puts all on a level playing field. :)

Variations in weather, geography, options, etc. all play a role in mpg calculations so there is no exact method for determining consistency. This method merely takes the overfilling/underfilling variable out of play as much as possible. ;)

Skoryaro2, you likely took more time developing that post than I did the mpg method! ):h Funny though! :funnypost

So is it a good idea, needs modifying, ???? I figure guys could preface any mpg post with "DP MPG's" so we know they have used the standardized method. Good discussion though. Hopefully the guys that live/breathe their mpg's will find this helpful. Later. JJ :)

I got 20 in my 2005 LLY CC SB allison this weekend. That was about 60 miles of city driving, and the rest highway at 65mph. I was takin' her easy, with the Predator on 40, to see what kind of milage I could get. The DIC said 25...

Woah, too many posts to keep up with. :D

Each of us is different. If you want to wait 5k miles then divide the gallons used go for it. That certainly is simple. :) I suspect those that live/breathe mpg's won't be satisfied with that method. If they are like me they compute every tankful, if the numbers are low they backtrack what they did with their truck that negatively impacted the mpg's. Yea, US ANAL BOYZ ARE OUT THERE! :ro)

My concern with waiting til 10 fill-ups is I'm not likely to remember what I did last week much less 10 weeks ago that might have sank my mpg's in the can! :( You need to compare the driving conditions of that tank to similar driving conditions with other tanks for consistency. :confused:

For example, sometimes I'll tow the 5ver to the house for clean-up and service(20 miles round trip), take it back, then hit the road for a while. Those initial mpg's with the 5ver in tow in stop/go traffic are likely in the 5mpg range:( , whereas the highway is somewhere around 17-18mpg's;) . IMHO there shouldn't be too wide a span in calculations. :cool:

The most accurate is by the tankful, either city driving with frequent stops and slow downs, OR highway driving at consistent speeds for extended distances. :confused: If we're not careful this can get way too complicated. It is likely best to limit DP MPG calculations to either around town driving or highway driving over extended distances. Also, calculations by the tank may avoid/minimize changes due to temperature drops, Diesel 1 fuel versus #2, etc. already mentioned. :rolleyes:

The jest of this is to set a standard by which mpg's are calculated minus all the variables for weather, tires, etc. so that others with similarly equipped trucks can compare their mpg's to a comparably equipped truck. A "stock" 2500 CC 4X4 in Florida should achieve comparable numbers to the same truck in similar climate conditions, like Texas, Louisiana, etc. Is this simple enough?

Hopefully let's not get too convulated over or wrapped around too many variables. This will never be an exact science! What I'm proposing is that if your going to post MPG's on the DP then use the standardized method for computing them, SIMPLE ENOUGH! :) Good discussion. JJ :)

Method for calculating mileage:

Round all numbers and then add or subtract 2-15 miles per gallon to arrive at a number significantly better or worse than you are actually getting so that you may either brag or ***** depending on your mood.

...The most accurate is by the tankful, either city driving with frequent stops and slow downs, OR highway driving at consistent speeds for extended distances. ...
I am not so sure of that statement. Too many variables come into play. The most precise method may be by the tankful, but not the most accurate. The most accurate is to take the average. By recommending at least 10 fill-ups, I wasn't meaning that you should never check the mileage on each tank. I was merely suggesting reporting only the 10-tank average. For the anal folks, calculate it each time, but when reporting numbers, add up the total number of gallons and divide by total miles. DO NOT just average the calculated mileage from a given number of tanks. The two methods will not give the same results.

I know there are many that are reading this thread and shaking their head and laughing. I can't speak for others, but I am a scientist and lately almost all I do is multivariate statistical analysis, so that is my excuse for being this anal about something so trivial.

"I know there are many that are reading this thread and shaking their head and laughing. I can't speak for others, but I am a scientist and lately almost all I do is multivariate statistical analysis, so that is my excuse for being this anal about something so trivial."

They might be shaking their heads, but mostly at the pumps! :o: Some of the more heated posts on the DP are about mpg's. There are the winners posting high MPG's :D, and the non-winners posting terrible mpg's :( .

Same trucks, differing mpg's. Everyone loves the power these diesels put under our foot, but for some reason we still worry about getting great mpg's. I don't believe this is just an anal issue, the boyz are reading, but only us anal types are willing to talk about it in public. ):h

IMHO the averages have to be under the same operating conditions to hold true under the scenario presented. Over a 10 week period I'll do 3 weeks towing, 4 weeks city, 3 weeks highway(3+4+3, 10 right:p: ). While the 10 week mix will yield an average, it isn't an accurate reflection of the mpg's for how the vehicle was being worked while yielding those results. :confused: OK, this isn't simple anymore! :o:

What I was really shooting for was for posters to use the same method of calculating mpg's depending upon the particular useage of the truck. I post three different mpg's on the forum: mostly city/traffic; highway; and towing heavy. :)

Hmmm, a multivariate statistical analyst! Why does that sound like sssssssooooooooo much fun! JJ :) :exactly: :help: <!-- / message --><!-- sig -->

I do my calculation at every fill up. I do not have a DIC(I have a dinosaur 2001 LS model ):h ). I always fill mine on level ground as most stations are built pretty flat at the pumps. I fill until the nozzle shuts off then pump until I can see fuel in the fill neck(this is usually another 3 gallons after initial shutoff). I have done this since purchase and even after addition of 56 Gallon TFI Tank. For the last 6 tank fulls, I have averaged 15.9, 15.6, 15.8, 14.4(towed a 5K trailer for about 150 miles) 15.5 and 15.9. The 5 were daily driving, 30% freeway, 70% around town. I have had the Edge installed on these tank fulls and have it set at 3. Speed is always 70+ on freeway and 70 when I can do it around town.....:lol: ...Ok Ok..Just Kidding, Most is 35-50 around town. The last 3 tank fulls lasted me almost 4 weeks between fill ups which is excellent.

I agree that there is severe difference in the MPG stated between owners. However there are a tremendous amount of variables that effect this: driving habits, weather, idling, speed. and so on. Quite frankly I think the entire MPG thing is a waste of time if you plan on comparing, use it as your tool but never read on a web forum trying to figure out why owner XXXX gets 22MPG in the same truck that you are only getting 15. I think JJ is right in the fact that you monitor tank to tank as a tool to see if something is not right. That is the only reason why I do it. As you can see from my numbers above there are people that get better MPG then I do, But that is them, not me and I do not use for comparison.

Double D, music to my ears! :exactly: I agree 110% with your statement about trying to reign in mpg numbers on a website, but dang if the guys don't get wrapped up in it just about every week. :o: What I proposed is that if you are going to post mpg's on the DP you do it by a set standard. It takes one large variable out of the mix. Then its off to the races with all the other variables! ):h Good post! JJ :)

JJ, I do every tank.......donno why? I'm not going to drive with any less vigor. Anywho, I do every tank. I have city and hwy numbers. However, a 5k avg. would really cut to the chase. Two fellas on the road and one get's 16, the other 19..... and the hours are the same, then we look at load, idle time or something. Maybe I'm crazy but each car/truck I've had has had it's own way of burning fuel. My 350's seemed to have gotten better MPG than my 300's..... why..donno? Hell, the 350's were worked 'a lot' harder.

I should have been more clear in my request for posting averages that they do need to be over relatively the same type of driving conditions to be meaningful. You can't average two tanks where one is towing 10,000 lbs and the other is driving 55 mph down a country road and expect it to mean anything.

What I hoped to avoid by people averaging at least a few tanks was random variability of weather, how full you fill the tank, etc. If you average several tanks, you should eliminate as much of the random noise as possible and be able to look at "real" variability between trucks. I also think many post their best numbers and seem to forget their worst numbers. Like I could say my truck gets 22.6 mpg, which it did one tank at one point in its life. I could also say it gets 11 point something which I think is my worst ever. Neither of those are quite as meaningful as saying it has a lifetime average (70-34,838 miles) of 17.8.

Habanero, agreed! :D Hopefully what we can all agree upon is that regardless of which time period we use (each tank/5k???) we will consistently fill our tanks using the DP MPG method. Guys like myself, DD, Burner, etc., that calculate every tank can compare with each other. I under-estimated how complicated this could get. :o:

Also, your statement about posting the best versus the worst mpg's likely holds true in most instances. I'm just looking for a way to level the playing field a little bit. I know there are guys out there unhappy with their trucks because they think everyone else is getting better mpg's when in reality they are closer than they think. ;)

Duramax Dually's statement "I fill until the nozzle shuts off then pump until I can see fuel in the fill neck(this is usually another 3 gallons after initial shutoff)" is my experience as well, especially at truck stops. Ever wonder why the ground is so filthy at truck stops. The truckers set the nozzle on high then go about washing windows, mirrors, etc. The pumps at truck stops pump so fast the nozzles can't disengage fast enough to avoid spilling out. After click-off I can usually get a minimum of 3 gallons more diesel in my truck at truck stops, whereas at regular gas stations I might squeeze another gallon, rarely 2. :confused:

IMHO most guys that post mpg's are doing calculations by the tankful. If guys are posting mpg's with a 3-5 gallon variance from those that carefully "fill er' up" they will consistently post higher mpg's when in reality they are getting no better than most other trucks. :o:

Is there a better way to reign this in? Like I said on my initial post there is no pride of authorship on this. I'm just tired of reading the multitude of MPG tirades(?) and sitting there thinking to myself "are they comparing apples to apples"? :confused: Anal? Yea Baby! ):h Right down my alley! ):h

Burner states "JJ, I do every tank.......donno why?" I do! :cool: Yo' anal to baby! :D JJ :)

...Duramax Dually's statement "I fill until the nozzle shuts off then pump until I can see fuel in the fill neck(this is usually another 3 gallons after initial shutoff)" is my experience as well, especially at truck stops. Ever wonder why the ground is so filthy at truck stops. The truckers set the nozzle on high then go about washing windows, mirrors, etc. The pumps at truck stops pump so fast the nozzles can't disengage fast enough to avoid spilling out. After click-off I can usually get a minimum of 3 gallons more diesel in my truck at truck stops, whereas at regular gas stations I might squeeze another gallon, rarely 2. :confused:

IMHO most guys that post mpg's are doing calculations by the tankful. If guys are posting mpg's with a 3-5 gallon variance from those that carefully "fill er' up" they will consistently post higher mpg's when in reality they are getting no better than most other trucks...
This illustrates my point exactly. If you keep a running average, you don't have to sit there and dink with the fuel nozzle trying to stomp that last gallon in. Dad drives me up the wall as it takes him 30 minutes to fill his tank with all the squeezing he does to "get a good mileage calculation". If you keep a running average, you can avoid that. If you put a little more in this time, your mileage will look a bit worse. But next time, you will put in a little less (or will be able to drive a little further on the extra you put in before), and your mileage will look a bit better. As long as you divide the total number of miles by the total number of gallons, no matter what the time period-2 tanks, month, year, lifetime, whatever, you are getting a more accurate reading of the actual mileage. Of course you have to take into account usage, but that can be handled simply by adding a note on the receipt while it is fresh in your mind. Then when you go back to do your calculations, you can categorize your receipts into towing, city, highway; then do the calculations of each category separately. It really isn't that hard and you will spend much less time writing a little note on the receipt than you will trying to get that last gallon in the tank (plus you're less likely to spill diesel down the side of the truck).

For expediency let's just agree that there are several options available to compute mpg's. :o:

Those that just want an average over an extended period of time can do so by calculating the miles driven versus gallons purchased over a specified period of time. This will include a combination of both city, highway, towing, idling, etc., whatever has occured during that time period. We'll call this the "non-anal crowd"! :D

For the "totally anal boyz and girlies" that want to know their mpg's under specific applications such as towing, highway, city/traffic they will need to calculate the mpg's after performing those specific evolutions. Easy enough! :)

To each his/her own! For those that follow the proposed DP MPG fill-up procedure at least I'll know what to compare to when looking at the other variables. Later. JJ :)

lets just all get togather drain all the fuel out of the tanks put one gallon in and see who goes the farthest thats the only way to compare too different trucks and there drivers

arctiva, you've been a member since March 04, posted 12 times, and a MPG thread gets you to post! I'm honored! :ro) Your idea isn't very anal though, funny, but not near anal enough! ):h Later. JJ :)

Warning! Warning........Will Robinson! DP MPG reporting violation has occurred on this thread here (http://www.dieselplace.com/forum/showthread.php?t=29621) Immediate action must be taken.

This has been an automated response....this message will self destruct in 5 seconds!

:muahaha:

Skoryaro2, you are showing your age my friend. Unfortunately I used to watch that show as a kid myself. :o:

For those of us that check their mpg's each tankful this is absolutely no more work since we're going to take the time to fill the tank as was prescribed. Call us "The Anal Boyz"! ):h :confused: Oh yea, we're out there. I'm receiving PM's from other "Closet MPG guys". :cool: Come on out boyz! :p: JJ :)

Your one funny S@B JJ !!!!!!!!!!!!!!!!:lol:

As long as you fill the tank the same way each and evey time I cant see what diff that could make:o:

Wont be long and this is going to get outa hand):h

OK, JJ's getting tired and needs a cold one. :o: Here is a copy of a reply to a PM I received. Maybe this will shed some light on why I recommended a consistent fill up procedure. If not, I'll drink mo' beer! :drinking:

REPLY: Yes it sounds pretty simplistic on the surface. You are actually filling your tank following the method that I proposed so your numbers would be consistent. But there is a reason I suggested this. :confused:

In a scenario where someone fills their truck until the pump clicks off there can be as much as a 3-4 gallon or more difference between truck stop pumps and regular gas station pumps due to the rate at which they dispense fuel. :rolleyes:

So if Bubba #1 fills up at a regular gas station, pump shuts off at 30 gallons in his tank after driving 450 miles, he's happy at 15mpg. While Bubba #2 drives to the truck stop across the street after driving the same distance in the same truck only to have their high volume pump kick off at 26 gallons. 450 miles divided by 26, uh 17.30mpg. Bubba #2 posts higher mpg's on the DP unaware there is another 4 gallons of tank capacity to be filled. Bubba #1 is pissed, especially with the price of diesel right now. :mad:

Trivial? Yes! If you follow many of the MPG threads on the DP it is quite a lively subject. All I'm proposing is we bring some consistency to one of the major variables by ensuring we completely fill our tanks when computing mpg's. Hope this helps. Anal? Yes! Possibly even Super Anal! :ro) Later. JJ
:)

Nuff said! :exactly: The "Super Anal" guys such as myself, and you know who you are:cool: , will follow this procedure now that they are aware there can be so much inconsistency. ;)

Those like Mama JJ that couldn't tell you how many gallons they pump, never reset the trip odometer, or could care less about variables will continue as well. When I post my mpg's on the DP they will be annotated as "DP MPG computed at ???" Those of you "in-the-know" will know I'm posting accurate mpg's. :ro)

That's all I'm going to say. JJ has left the building! :cool: JJ :)

JJ, I've really enjoyed this post, and admire the tenacity with which you try to being sense to the science of MPG posts. :ro)

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I also have noted the great interest in this topic, diverse opinions (arctiva, great idea, can we come to your place), and think we should seriously consider starting an Anal DP MPG Club for those of us that agree with your methodology. Think of the T-shirts. ;) <o:p></o:p>

"JJ, I've really enjoyed this post, and admire the tenacity with which you try to being sense to the science of MPG posts." :ro)

Tenacious JJ, ruff! ):h Any of you following the current "MPG b'atch-session" going on in the LLY forum? Not one of them is using the same variables in their MPG computations! Tish tish! :D

I know, SHUT UP JJ! :exactly:

Okay, I tried my best but I just can't let this rest...

Your Bubba(s) example highlights my preference for reporting tank averages. Let's say Bubba #2 just doesn't have time to fiddle-fart around getting that last few gallons in the tank. If he keeps a running total and does the average over a couple tanks, he will see his average come back to the same as that of #1 since he won't be able to travel as far on his 26 gallons as #1 does on his 30. Just keep two running totals: the amount of fuel you put in, and the amount of miles you have driven. Do it over say 2-3 tanks (more if you have consistent driving habits like most of us do), and at the end divide the total miles by the total gallons. Report this number along with any pertinent information (city, highway, towing, etc.)

You can still do your calculation after each fill to get an idea of how it is doing, but you will have more valid data to report by taking the average. You don't have to be that computer-savvy to set up an analysis spreadsheets in Excel for tracking these types of things. If any body wants a template, pm me your email and I will send you mine.

Habanero, your patience with ol' JJ is much appreciated.:) I see where you are coming from. My approach was more towards mpg's for specific applications such as for towing, city/traffic or interstate highway driving. Trying to decipher how many gallons in a particular tank were used for each would prove difficult and likely unreliable for most of us. I agree that guys that drive the same from day to day can obtain a better average by doing it over an extended period. :)

It appears most of the guys that post mpg's on the forum tend to check them while performing one of the 3 above versus a combination of them. Towing mpg's can run between 5-12mpg, mixing interstate driving with towing won't allow one to determine how much was used for towing versus interstate, or would it? That one is above my brain power.:o:

For me I'll continue to fill my truck using the DP MPG method I proposed, then tow my 5ver down the road, fill er up again when I unhook the 5ver and do the math. Same for city/traffic and highway. Simple enough for me. JJ's out! :D

On edit, Anal DP MPG Club, I like the sound of that!

OK - It's out in the open on another thread that I too check my MPG's on every tank and am anal about it (I had to come clean, but only after giving JJ a hard time).

That said, I follow the "fill until it clicks, let it settle and fill slow until I can just see the fuel method". As a double check, I know that as my fuel gauge (under nromal driving) comes off of "above F" and starts to move off of the full mark that I should have gone about about 45 miles on the present tank. Wife thinks I'm nuts because I play the "I can guess how far I've gone" game just by looking at the fuel guage. Usually I can get within 5 miles of being correct :)

Skoryaro2 states "I can guess how far I've gone" :rolleyes:

Perfectly normal! ;) ):h ):h ):h :exactly:

Habanero, where ya at dude? :D JJ :)

:HandshakeWe are slowley coming out of the woodwork:lol:

OK, JJ's not giving up that easy! :D BUMP, BUMP, BUMP! ):h

Since I posted this thread there have been no less than 3 threads started on MPG postings where guys are using their DIC's, road signs, lunar occlusions, beer counts, etc., to figure MPG's. Those posting high mpg's: happy! Those posting low mpg's: sad! :wtf1:
We need mpg consistency across the forum. So? :Get_him: JJ :)

JJ, I was attempting to follow the DP Anal MPG refueling rule on my last fill up, and was wondering how long to pause between each of the three successive low flow rate shutoffs. If I restart pumping immediately, nozzle is still in foam, and it seems to shut off immediately. The longer the pause, the more fuel I can squeeze in.

So what is the point in having a DIC if we shouldn't use it?

Jackpine, music to my ears dude! ):h As you've noticed diesel fuel foams up, especially at high flow rates like truck stops. You don't want to rely on the pump shutting off quick enough to avoid spilling onto your truck. Let's face it, this sh_t is nasty! :o:

Being that I'm anal I usually have a rough idea of how many gallons I'll be needing to fill up, so I'll pump full speed 3/4 of the way, half-speed the remainder. Usually I can listen and hear the tank getting near full, but at truck stops that's about impossible. You can usually see the diesel foaming up in the filler neck before it overflows. Good luck with that! ;)

After the first click off, let the diesel drain down the fill tube until you can't see it anymore, then slowly pump more diesel until it rises near the top of the fill tube, then stop pumping and let the foam drain back into the tank. Do this two more times. Per your owners manual you don't want to fill it so full that you can see diesel sitting in the fill tube, I don't know why, but they say don't overfill. :confused: Simple enough! :) Refill the same way next time, divide miles driven by gallons pumped, wallah! :ro)

If those of us posting mpg's would follow this same procedure we would know we're comparing apples to apples as closely as possible. While not perfect, it gives us a measurable standard to go by. :)

CS, now that sounded really nasty! ;) But I know what you meant so you still cool dude! :cool: I guess the simple answer is for mpg's DIC's have proven too unreliable and inaccurate. I don't have a DIC in my truck, but they must serve other functions as well so enjoy those. :rolleyes:

Hope this helps. JJ :)

So what is the point in having a DIC if we shouldn't use it?
He has a DIC and wont use it:lol:


I hand cal. my out.. Highest has been 24.2 and have had 23.8's also. I also have a lighter truck than most. 6750 lbs with driver and normal load of junk. Speedometer has been corrected for tire size 285's. I run back and forth to work on back roads "southeastern Kentucky". On the backroads I avg 21-22 mpg. I do have a ZF and I do work the bottom end of the powerband. I think this helps my fuel mileage the most. As far as doing a 5k avg. that could lead to problems. I also watch mpg to watch for signs of trouble. Idle time on the farm along with towing up and down billygoat bluffs would throw the avg. balance way out. Do a interstate/highway bobtailing avg. Innercity avg. and a towing avg. to justify it all.


just my .02 worth.........hmmm now fuel is 2.09 a gallon, 2 divide into 2.09 is 104.5.....times 22 mpg.....that almost 2/10's of a mile:joke:

coalbucket1 states: just my .02 worth.........hmmm now fuel is 2.09 a gallon, 2 divide into 2.09 is 104.5.....times 22 mpg.....that almost 2/10's of a mile

CB1, you're not playing with ol JJ's emotions are you? Calculating down to that level qualifies you for the "Super Duper Anal Club"! ):h Might even make you President. :ro)

Slowly more and more guys are starting to use the proposed "DP MPG Calculating Method" for computing their mpg's. Those that post using this method will let others know they're not pulling their mpg's out of their ???, well you know! ;)

CB1 got me thinking, dangerous! :o: If I wasn't clear on my initial post, if you have a combination of the big three, i.e. highway, city/traffic and towing, you are not going to have an accurate read on any of the three during that tankful of diesel. Best to calculate mpg's on a tankful dedicated to performing that particular type of driving only. Thanks CB1. :D JJ :)

Bumping this back up to keep the DP MPG Calculating method on the radar screen. I'm noticing guys posting using this method more and more. It's nice to compare MPG numbers with guys that are using the same fill-up method. :exactly: JJ :)

I fill it up until it won't hold another oz, I then drive it untill it need fuel, I then fill it up the exact same way, and in most cases at the same truckstop on the same side of the pump. So my calculations can not get any more accurate. And over 10`s of thousands of miles, it is very easy to take accurate readings.

Does anyone know exactly what a gallon of diesel fuel weighs? I propose that we weigh our trucks immediately before and after we fuel up. That way we would know exactly how much fuel we put in. Of course, someone will add their fuel additive before the second weigh-in and screw-up our whole system again! Oh no! Wait - winter and summer blended fuels may weigh differently. So, from March 1st. each year through September 1st. each year you can only post your MPG's if you've run summer fuel. From September 1st. - April 30th. you can only post if running winter fuels. No wait! Some areas of the country may not change fuels during the year. Ok - Lets divide the country into 4 quadrants. The Northest quadrant can only.............awwwww forget it!!

Just funn'in ya JJ - you have way too much time on your hands :)
So you think we should spend $14-$16 to the cost of our $60 fill-ups!
:eek: Besides that, do the places you fill-up have a weigh station at the pump? Because the truckstop I use has the weigh station in a different part of the station, nowhere near the pump. And that means you have to start and drive the truck at least once, and you may need to wait. Poor idea!

Just keep a log of each and every fill up from the first fill-up until you sale the truck, and it will be extremely accurate. And you will save 100`s maybe 1,000`s over having the truck wieghed twice at every fill-up :eek:

Well, being as anal or OCD as the next guy, I use the same procedure every time and enter it into my spreadsheet found in the link below. I alternate my OEM and aux tank at every fillup. I shift tanks when the "low fuel" light comes on. When refilling the off-service tank, I put 32.0 gallons in the aux and anywhere from 24.0 to 24.2 in the OEM. Miles driven on the tank divided by gallons used. Aux tank has always had a fuel level about 1-1/2" from the top after filling every time I've checked and OEM has to be "burped" and foam allowed to settle to get the last gallon or so in the filler.

IdleChatter, music to my ears bro! Those that are anal and OCD need a special place! ):h Hard to imagine ever getting anything done analyzing things to death while cleaning up and organizing at the same time! ):h My father-in-law is OCD, the anal part is slipping in his old age. Hard to please, impatient as hell, and can't tell him a dang thing! God I love that old fart! :D

hdmax, I like the fill up routine. ;) JJ :)

I might be giving age away also. I have been logging every tank in every truck for many years. I have 144 half to three quarter tanks solo logged on my truck. My solo average is 18.49. With this many logged a tank of 22 or 12 won't change my average much if any. It is JMHO that 5K will not make a good average but 12 months will. I can pick the same four months in the past three years and tell you my average was within 1/10 th. I might be a little anal but am retired and have the time. Later! Frank

I think Frank needs to be a member of Quad "A", what do you think JJ?

(JJ, not just a memberof Quad A, he's also the founder )

Sure sounds like he suffers the "AAAA" affliction. JJ :)

Does anyone know exactly what a gallon of diesel fuel weighs? I propose that we weigh our trucks immediately before and after we fuel up. That way we would know exactly how much fuel we put in. Of course, someone will add their fuel additive before the second weigh-in and screw-up our whole system again! Oh no! Wait - winter and summer blended fuels may weigh differently. So, from March 1st. each year through September 1st. each year you can only post your MPG's if you've run summer fuel. From September 1st. - April 30th. you can only post if running winter fuels. No wait! Some areas of the country may not change fuels during the year. Ok - Lets divide the country into 4 quadrants. The Northest quadrant can only.............awwwww forget it!!

Just funn'in ya JJ - you have way too much time on your hands :)

So you think we should spend $14-$16 to the cost of our $60 fill-ups!
:eek: Besides that, do the places you fill-up have a weigh station at the pump? Because the truckstop I use has the weigh station in a different part of the station, nowhere near the pump. And that means you have to start and drive the truck at least once, and you may need to wait. Poor idea!

Just keep a log of each and every fill up from the first fill-up until you sale the truck, and it will be extremely accurate. And you will save 100`s maybe 1,000`s over having the truck wieghed twice at every fill-up :eek:

Is it possible that hdmax really thought I was serious with this??
:eek:

You were kidding! :eek: :wtf1: ):h JJ :)

Ok, I've been lurking in the background and have finally decided to voice my opinion. I have tracked every tank in my truck from day 1. So to eliiminate the mysterious "when is the tank really full" issue, I fill my tank until the fuel level is just under the top of the filler neck. Granted this takes an extra 5 minutes or so of packing fuel, but I know that I have the same reference point every time.

I have a pre-dic vehicle so all of my calculations are by hand. I keep 2 sets of books, so to speak, one set includes solo and towing and the second set is solo only. I am one of the few with a hand shacker and am relatively easy on the truck. Solo from day one through 115k miles, my average mileage is 20.3. My commute to work is 80 miles round trip, 45% in town. Needless to say, I am one of the tickled $hitle$$ individuals. Good power and good MPG.

MaxRock

Maxrock, we saw you lurking:cool_shad , we were just waiting for you to pop up on the radar screen! ):h Glad to see you using the same method each time to fill er' up! :D
"I have tracked every tank in my truck from day 1. " :rolleyes:

Ooh, "Quad A" material if I ever see'd it! ):h Later. JJ :)

JJ,

I got one for you...I fill up as others do...to the neck but.... Sometimes I top of at home??? I mix biodiesel and top off in the morning right to the neck...truck has been sitting overnight...fuel is ambient temp.

Allow a few minutes for the truck to burp....refill. She's my baby.

Drive say 200 miles and refill to the neck....hot fuel...while truck is running at retail pump.

Am I getting a better MPG calculation because I am filling up cold and refilling hot???

How about that for being retentive?

Surprised no Canadian's have jumped in here! So here goes...
My DIC reads litres per 100kms! And on the current tank its reading 12 litres per 100 kms! Confused yet? And this by the way is 19.6 miles per US gallon or 23.5 miles per Imerial gallon.
I do still hand crank the numbers...but here again we differ because I grew up on Imperial gals!
1 US Gal = 3.785 litres
1 Imperial Gal = 4.546 litres
So a US Gal is .8326 of an Imperial Gal! (3.785/4.5446)
I also happen to carry a metric conversion calculator in my pocket.

And by the way diesel in this area is about $.85 Cdn per litre...and now you have the exchange to consider too! Today its about $.80. So our litre of diesel is about $.68/litre in US $$ and $2.57 per US gallon.
Thankgoodness for my little calculator friend!

Cheers,
Richard

do you have a pocket protector too...

just kidding...lol

JJ, i see plent of fresh meat for the Quad A club (aka - QAC)

Holy crap, what have I done? :eek: All these strange variables and questions! What to do, what to do??? :rolleyes:

:wtf1: Truly anal types would let this bother them until they found the answers. Uh-oh, somebody stop me! :D

RonJT, since the diesel fuel you are pumping at the station is coming from underground tanks it is cool as well, likely cooler than your home brew. Mixing it with the diesel fuel in the tank that has been recirculated and cooled. Not sure just how warm it is, or how much diesel fuel expands/contracts with temperatures. Any Quad A's out there know the answer? :confused:

AYR Time, loved your post. Gave me my first Quad A "chubby". ):h JJ :)

To be truly accurate you would need the temperature of the fuel to be the same at each fillup. Diesel like other liquids is subject to thermal expansion and contraction.

On a hot day you will actually have less fuel by volume than on a cold day. Also a nice hot truck that has its fuel tank already nice and warmed will take on slightly less fuel than one that gets fired up cold, idles down the street, shuts off, and refuels.

The difference between the two will vary your mileage.

The person earlier was correct in saying the most accurate way was to weigh to determine fuel added. Good luck though at instituting that one!

Yet people call me anal? ):h TxC, great post! You really should update your sig with the new "AAAA" sign. ;)

I whole-heartedly agree that obtaining an exact measurement of just how much fuel was consumed over an exact distance is impractical for the average smuck like JJ. :o: IMHO it is easier and more practical to just accept these variables and utilize the most simplistic method for computing mpg's: miles driven divided by gallons pumped. While not an exact calculation, it is certainly within the margins and acceptable to myself and hopefully to others as well. ;) The only time my truck goes on the scales is when the 5ver is behind it for legal and safety issues. :exactly:

The intent of my initial post was not intended to give us an exact measurement of mpg's, moreso just to have people follow a standardized fill-up method in order to gain some consistency in how we were computing mpg's. :D MPG threads can bring on some pretty hot posts, especially when the 20mpg posters run into the 16mpg posters! By using this method at least they know they are coming fairly close to comparing "apples to apples". :D

It was reassuring to note the Quad A's that were pretty much doing it this way anyway. No surprise though! ):h Hopefully this thread has helped? I am always glad to see guys posting using the DP MPG Calculation method. Later. JJ :)