Tracking fuel mileage(longterm)

[CATCRACKER]

I am starting this thread which I will be updating regularly to give a some truthful insight what these new 3rd gen's MPG will be. I am going to clarify driving style, mods, city/hwy etc. These will be calced using fuel top off method and corrected for 315 tires 9%. I idle the truck many times when i am running into the store real quick or something. I also let my truck idle for 3-5min before driving in the morning regardless of how cold or hot.



TRUCK: 03 ETH/DEE QC SRW 3500 4x4 Limited Slip 3. 73 150#s worth of tools in back.



[12. 19mpg]99% city

2/11/03 (before 315's) 573 total miles on truck /219 on tank miles/ 17. 958 gallons/12. 19MPG/computer said 14. 7/all city heavy foot 10 WOT/no additives avg. 55 degrees



[15. 87 mpg]35%city

2/19/03 (before 315's) 419 miles/26. 241 gal/15. 87MPG/65% Hwy 5 WOT/no adds



[15. 8 mpg]

3/05/03 393 miles/24. 119 gal/ lucas additive all city med foot shifting at 2100/2200 never falling below 1500 rpms



[15. 48 mpg]95%city

3/21/03 warm temps 60's(after adding 315's) lucas and redline additives computer said 14. 6



making a long trip to mississippi for a turkey hunt so i will get some hwy cruising #'s w/ no additive 65 deg. at 70mph i will somewhat flat. report on mon. i am expecting about 17. 5-18 at least, but we will see and i will report the truth. early impressions is that while not being broke in yet this truck under normal drving condition like about 15. 5 mpg maybe a little higher with additives.



hope this will shed some light on true mpg's seems to be increasing with age and my foot is starting to relax a little but not too much.

 

[Vaughn MacKenzie]

Good idea for this thread Cat. Just curious, why do you idle so long in the morning? I know, getting off the subject.



Vaughn

 

[Prairie Dog]

I agree with Vaughn, This is a good idea. Another thread eluded to the possibility of lower mileage after C02 was installed. I'd sure like to know if thats the case before my dealer does this when it's in the shop next week.

By the way, I picked up 2 MPG this last week from reducing my speed f/ 65 - 70 down to 60.

Man it's hard to drive that slow though

 

[preleeguy]

I'm surprised

I've been reading all the posts about the mileage others are getting and I'm puzzled. I'll admit I'm kind of an older guy and generally not in too much of a hurry,but nobody runs me over in town or on the road. I monitor every tank and check the mileage manually and compare it to the MPG gage. I find the on board gage to be fairly acurate. Maybe at the most 1mpg off,but mostly within a few tenths of what I calculate. I get a steady 20+ mpg. My lowest non-towing rate has been 19 and my highest 22. 5. So you see why I am puzzled that others are getting so much less. Maybe we don't have winter blend here in Texas. Or maybe the 6 spd helps some. I try to shift between 1500 and 2000 mostly. Going through the gears quickly as possible helps I'm sure. Sorry to get long winded. Surely others can match these numbers on a regular basis without much trouble.

 

[SmokinJoe]

Re: I'm surprised

Originally posted by preleeguy

My lowest non-towing rate has been 19 and my highest 22. 5.

I was driving 5 miles to work/gym and was getting like 17 mpg. If I really ragged on it I would get 15 mpg. With a two axle car trailer hauling a Dodge Neon from Memphis, TN this summer we got 16. 98 mpg grossing 13k according to the CAT scales. We had 1,000 lbs of junk in the truck at least. My brother was REALLY impressed.



I am now driving 65 miles to work one way. I am allowing my gear oil to warm up before going 58mph to work. In the 65 miles to work/gym I have 7 rolling stops with a 90 degree turns, three traffic lights and two 90 degree turns. The oil/air temp play a big deal as well as speed. I have all 30,000 miles logged in a fancy spreadsheet I have made. If anyone wants it I can send it to them, they can compare it to my truck...

 

[Prairie Dog]

Preleeguy, Is your rig a 2WD? That would make a big difference. Also I noticed that people seem to be getting an incredibly wide range of fuel mileage - I've read about as low as 12 and as high as 21.

I drive like you describe and I've gotten between 16. 4 and Smokin Joes 19.

 

[Briman]

I Agree with Preleeguy in that shifting below 2000 RPM is the way to get better mileage. Thats hard to do though, when that interstate on ramp is beckoning and your HO is willing.

 

[Vaughn MacKenzie]

Shifting revs depend on situation

The more of a load you have or the quicker you accelerate, the higher you should rev it between shifts. IMO you'll get worse mileage lugging it than revving it. When I'm loafing along in town I run around 15-1800rpm, when I accelerate quick it's 2400-3000rpm shifts.



Vaughn

 

[preleeguy]

My ride

I should change my sig. It's a 2500 2WD. Short bed,W/3. 73 gears.

 

[jimnance]

I GOT BETTER FUEL ECONOMY WITH THE STOCK TIRES (19 MPG HWY) THAN MY 315'S (17 mpg). THESE ARE HIGHWAY NUMBERS UNLADEN.



I GUESS SWINGING THE BIGGER MEAT AROUND IS HURTING FUEL ECONOMY. I EXPECTED THE OPPOSITE TO BE TRUE.



ALSO, THE BRAKES SEEM A BIT LESS EFFECTIVE WITH THE BIGGER TIRES.

 

[jimnance]

I GOT BETTER FUEL ECONOMY WITH THE STOCK TIRES (19 MPG HWY) THAN MY 315'S (17 mpg). THESE ARE HIGHWAY NUMBERS UNLADEN.



I GUESS SWINGING THE BIGGER MEAT AROUND IS HURTING FUEL ECONOMY. I EXPECTED THE OPPOSITE TO BE TRUE.



ALSO, THE BRAKES SEEM A BIT LESS EFFECTIVE WITH THE BIGGER TIRES.

 

[MMeier]

jimnance, did you have your speedometer recalibrated to compensate for the bigger tires? Picture what's going on here.

 

[Dean Upson]

I GUESS SWINGING THE BIGGER MEAT AROUND IS HURTING FUEL ECONOMY

It would seem reasonable to me that the more surface that you have on the road (bigger tires) the more friction you would have and that you would get less mileage. The same would be true with 6 vs 4 tires. I am sure that my dually gets less mileage than as SRW similiarly equipped.



Dean

 

[jimnance]

I compensate for the bigger tires by adding 9% to the indicated odometer mileage when figuring the fuel economy. I don't rely on the fuel computer.

Originally posted by MMeier

jimnance, did you have your speedometer recalibrated to compensate for the bigger tires? Picture what's going on here.

 

[Elk]

8. 6 with my 33. 5 foot toyhauler (3500 miles on the truck) My 97 pumped up would get around 12-14 with this same amount of weight. I am getting around 17 hiway and city. Temps around here in the 40s. I sure hope it improves.

 

[91W350]

17 roughly in the city and highway mixed, hard driving makes it dive to around 14. 17 at 70-75 leaving the cruise on and just shutting down for fuel. 22 at 60 fuel stop to fuel stop, but who can stand that? I have been cruising in the upper 60s and getting upper 19s, not quite as high as I hoped, but maybe it will come up with more miles. So far the computer has always been within two tenths, which I find amazing for all it has to compute in. Highway mileage has been within a few hundredths most of the time. Still kind of amazing though when the title weight said 6800 pounds. I like it!

 

[mgonske]

I'm not sure if this will be legible, but here's an annotated chart of my mileage to date. The low tank was 14. 1, the high, 19. 1 MPG.



I've also been tracking the mini trip computer readings against this, in order to obtain a calibration factor for it (there are two different calibration factors--one with, and one without, the EZ).

 

[LRoy]

At 4600-ish miles on a 3500 4x4, SRW, 6-spd - 18. 01, 16. 62, 18. 30, 17. 64, 18. 36, 18. 42, 19. 75, 18. 27.



first 6 tanks are highway driving (running 10-15 over usually), either empty or lightly loaded (maybe 1200 lbs). The last 2 tanks are casual driving, weekend errands, and a couple days of stop-and-go commuting.



These are calculated figures on stock tires. Trip computer seems to read about 1 MPG high, but I haven't paid enough attention to it to be sure.



Leonard

 

[CATCRACKER]

mgonske,



i like the info but its hard to read just type in your results or email me the results. this is good info. -- email address removed -- I am about to fill up and am going to post the results. In this 700 gallons worth of info i have about 15 WOT half city half hwy

 

[mgonske]

After reducing the image above enough to post it, I realized I could post a much larger (i. e. , more legible) one in Reader's Rigs. Go there and look in my "Installations" gallery for it.



CATCRACKER: The one I posted is a .jpg made from a PowerPoint 2000 presentation, and the raw data, along with other graphs, are in an Excel 2000 workbook--can you read those?