the REAL facts about fuel "economy" on the CTD trucks!!

[BBowers]

Ok, here goes, I have heard the whole shebang by now, guys and gals gettin anywhere from 14 to 22 mpg in an 05 dually quad cab like mine. I have my turbo silencer replaced with a pair of glued together pvc 4" pipe couplings sched. 80!! I have a bully dog triple dog programmer. I have 21k miles on the truck, delvac 1300 lube, fleetguard filters, tru flow foam filter, no kitty,stock tires and 3:73's, 4x4, automatic, powers svcs and marvel mmo added to fuel. I have never seen over 15. 5 mpg at 70 on anything but board flat ground and 5 mph winds where I maybe got 17 doing 60 mph. This is empty!!!!!!!!!!!!!!!!!!!! How can a 375 hp truck with the rack just barely cracked open, tons of low end torque to push air with, not lug, get such mileage compared to say a 2005 freightliner with an N14 or cat sommething or other with 11 liters of displacement, big fuel lines and rails, etc, and 80k lbs of trailer and cargo in addition to another say 15k lbs of tractor weight, (13 feet tall!!!) get about 6mpg???????!!!!!!! This is insane!!! 95,000 lbs, versus 8,000?? 13 feet tall versus 7. 5? 18 huge wheels versus 6?Our trucks should be getting 30 plus mpg empty!!!! maybe even 40!!!That or semis should get 1-2 mpg!! My source for fleet fuel economy is based on info from OVERDRIVE magazine, can't remember the issue, but it was no more than 6 months old. they discuss mileage in there a lot! Comments?

 

[JasonCzerak]

Have you tried the cruice control on the highway?



I know a few people that will speed up (60mph, slow down (55mph), speed up(60mph) slow down(55mph). Feels like a boat. Most don't even know they are doing this until pointed out.

 

[CATCRACKER]

afe, lose the the cat, taller street rubber, dont know that the triple dog will help, i know that the pressure boxes help but would not recommend one.

 

[IdahoJim]

You might be lucky, and have a tight engine. I know of several people who didn't start getting good mileage 'til they'd clocked 30,000 miles. I'd much rather have that situation then a "looser" engine that got great mileage right off the get go. Give that CTD a little time.

 

[JasonCzerak]

Yeah, Jim has a good point. I would suggest working it a bit. If you are empty most of the time like me. Run it hard, let that speedo needle hit 110mph once every few weeks.

 

[StLouisMO]

Have you checked with the dealer to see if there is a re-flash available for your truck. My truck was getting 13 to 14 average mpg per tank before I had mine reflashed. Now, after the reflash, I get average 18 mpg. If I get on the highway and travel between St. Louis, MO and Glen Carbon, IL (about 20 miles) and stick the cruise control on 65 miles per hour my overhead reads 24 miles per gallon. So, I'm happy with my mileage now after the reflash.

 

[klenger]

Some times stock is good. I'm getting 12 MPG unless I'm empty, then I get over 20

 

[lcaad1249]

Have you checked with the dealer to see if there is a re-flash available for your truck. My truck was getting 13 to 14 average mpg per tank before I had mine reflashed. Now, after the reflash, I get average 18 mpg. If I get on the highway and travel between St. Louis, MO and Glen Carbon, IL (about 20 miles) and stick the cruise control on 65 miles per hour my overhead reads 24 miles per gallon. So, I'm happy with my mileage now after the reflash.

After my reflash, the mileage stayed the same actually but the overhead went up about 3 mpg. I wouldn't trust the overhead.

 

[barbwire]

I put the Rokktech sensor on my 04, and picked up 1. 5 to 2 mpg. Don't know if it works on an 05, though. TAG helped it also. I get 15 to 17 towing a 24 ft. goosneck flatbed. Well over 20mpg, if I ever unhook from the trailer. Of course I have a 2wd, which makes a diff. All the little things I have done added up in benefits.

Just food for thought.

 

[ata]

I think you guys are MISSING BBowers point. 5. 9L to 11L, 8000# to 80000#, 7. 5 feet to 14 feet tall, 6 tires to 18 tires. These little pick-ups should be getting atleast 8 times better mileage. NOT TWO OR THREE times better.

 

[kblranch]

Then you have to factor in that my 2000 VW TDI @ 2500# (est. ) gets 42 MPG.

 

[BBowers]

Thanks for ONE person in TEN getting the point. the RIgs these days have LOW end ratings of 425 hp, and often are rated at over 500!!!! Yes, this is delivered at lower RPM, but not THAT low. 2100 is the lowest I have heard of on an old KTA19 1150 cid 19 liter cummins that typically developed 450 to 700 hp!! They went by the wayside in trucks as to emissions compliance problems but what great engines! Anyway, they are doing more with less these days with displacement, but I am sticking to my guns. WHERE IS THE FUEL MILEAGE? Also, I DO USE MY CRUISE CONTROL as often as possible. If I am on a stretch of road with no traffic lights, on goes the CC!! I try and play with the throttle to get the transmission to upshift early and keep the revs down. I try to get the transmission to shift up and lock up the converter as soon as possible to make use of the 600 plus lb ft of torque from the 5. 9. What is truly ridiculous is I have had guys respond to my query on economy in the past with claims of 19. 5 mpg with piers diesel street twin turbos making 600 hp!!! same truck as mine! Oh, and one last thing, I forgot to mention the extra 12 or so inches of vehicle WIDTH on the semi vs. dodge ctd comparo. Major difference in wind drag!!! So what gives? Are they purposely designed to eat fuel to keep us ignorant of how diesel could wean us off of expensive to produce gasoline? God forbid we all drive diesels!!

 

[Sled Dog]

Ok, here goes, I have heard the whole shebang by now, guys and gals gettin anywhere from 14 to 22 mpg in an 05 dually quad cab like mine. I have my turbo silencer replaced with a pair of glued together pvc 4" pipe couplings sched. 80!! I have a bully dog triple dog programmer. I have 21k miles on the truck, delvac 1300 lube, fleetguard filters, tru flow foam filter, no kitty,stock tires and 3:73's, 4x4, automatic, powers svcs and marvel mmo added to fuel. I have never seen over 15. 5 mpg at 70 on anything but board flat ground and 5 mph winds where I maybe got 17 doing 60 mph. This is empty!!!!!!!!!!!!!!!!!!!! How can a 375 hp truck with the rack just barely cracked open, tons of low end torque to push air with, not lug, get such mileage compared to say a 2005 freightliner with an N14 or cat sommething or other with 11 liters of displacement, big fuel lines and rails, etc, and 80k lbs of trailer and cargo in addition to another say 15k lbs of tractor weight, (13 feet tall!!!) get about 6mpg???????!!!!!!! This is insane!!! 95,000 lbs, versus 8,000?? 13 feet tall versus 7. 5? 18 huge wheels versus 6?Our trucks should be getting 30 plus mpg empty!!!! maybe even 40!!!That or semis should get 1-2 mpg!! My source for fleet fuel economy is based on info from OVERDRIVE magazine, can't remember the issue, but it was no more than 6 months old. they discuss mileage in there a lot! Comments?

Your Right!

 

[JayWm]

Speed kills... .



What your not reading in those fleet mags is that big fleets have the trucks speed limited to 65-68mph max. Tankers are limited to 57-59mph. I bet if you slow down your mileage will go way up. Big Rigs have done alot of work on the aerodynamics of the truck/trailer combos too. I have found with my dually that if I am empty I get about 14-16mpg if I am running on the freeway at 75-80mph along with some in town driving. Towing my very tall and not very aerodynamic box trailer at 65 mph nets me 13-14, at 70mph it drops to 12mpg and at 75-80 it goes to 10-11mpg. I have power so I tend to use it.



For the record, I'm with ya about the mileage though, please someone figure out how to kill the third injection event.



But, think about this, most 1st and 2nd gen guys are getting at best in the low 20's, and thats at best.

 

[Diesel Nut]

I certainly agree that speed does kill your mileage. I notice a large difference going from 65mp to 75mph. However, I don't see how one truck with 12k on the ticker is getting worse mileage than mine did driving off the lot with 27 miles on it. That's enought to **** off the pope! I was really worried about mileage going from my 03 that would regularly get 20+ at 65. Maybe I got lucky???

RPMs do have alot to do here, too. I think the N14 is governed at like 1800 or 2100 rpms. well, most of us are doing 2100 at 75mph. Also, the 1st and 2nd gen guys who are getting better mileage alos have 3. 55 gears, which may make the difference. Still, some of the horror stories I hear are just appauling. Oh, and not to flame anyone, but if someone tells me their late model truck is getting 24 mpg my guess is they are looking at the overhead and not calculating it, and the overhead is off. That or 90yr grannies are cussing at em on the freeway!! :-laf

 

[rjohnson916]

My trick is cruise control as much as possible on the freeway. Try to keep the truck around 68 mph. That seems to be my trucks most efficient range. Or anything below 2K on the tach. Roll of stop lights and stop signs gradually increasing throttle, letting up before you get to desired speed. If you know your going to stop soon, or see an intersection, idle down as you approach, rathar what most people do speed/up then brake hard. Try not to let the truck warm up too long or idle for periods. Monitor tire pressure.



-Ryan

 

[barbwire]

I am with you now, BBowers. It is VVVeeerrryyy difficult to understand. 8000 lb versus 80,000 is 10 times. Therefore we should get 10 times the mileage. Not to mention the width and height difference, as you stated. As some have mentioned, speed kills. But, when a person is running down the same road, at the same time,at the same speed, under the same conditions, as a semi, you are still only making whatever you make, and the semi is still making 6-8 or whatever. The light truck should make 60 to 100 mpg. Considering the differentials.

I know by reading here on the TDR, that there are some great minds in the diesel industry, that also read these threads. Yet, they cannot figure out the answer as to why these rigs don't get better mileage. Something is eluding us. When someone finally figures it out, the rest of the world is going to knock themselves in the head and say, " Man that is so simple, why wasn't that thought of a long time ago"?

 

[klenger]

My trick is cruise control as much as possible on the freeway. Try to keep the truck around 68 mph. That seems to be my trucks most efficient range. Or anything below 2K on the tach. Roll of stop lights and stop signs gradually increasing throttle, letting up before you get to desired speed. If you know your going to stop soon, or see an intersection, idle down as you approach, rathar what most people do speed/up then brake hard. Try not to let the truck warm up too long or idle for periods. Monitor tire pressure.



-Ryan

Ryan has it. I consistantly get 20 MPG around town and 12 towing. I try to keep my speed under 60 MPH.



Also, I don't think the 3rd injection event has any effect on towing milage as the events probably overlap at high power settings anyway, plus with the high EGT's there would not be any reason to add more fuel for emisions reasons.

 

[Tilesetter Too]

I've thought the same thing many many times. I'm a 03 dually 4x4 too. I often hit 20K lbs while towing and can get 8. 9-9. 3 and travelling 65-73, but unloaded 65-73 and 8,000 lbs, I usually average 13. 3-14. 3. I find it hard to believe claims of 14-15 towing when I dont even hit that empty. I think a lot has to do with how people fill up too. When I hand calc my mileage, I fill until I can't get on more drop in the filler neck and the same when I re-fill.

I relly need more in bed hauling capacity and am seriously considering a step up to a 4500 Chevy or F650 because what the heck, how much worse could the mileage get... .

Shawn

 

[Brock]

I just made round trip visit to Atlanta yesterday and today... ... a little over 600 miles round trip. Rolling hills and flat mix as I got further from lowcountry and up near Columbia then to Augusta and then into Atlanta area.....



Speed: On interstate between 65-75mph, RPMs 1800-2100 RPMs.

Wind: 3-8mph gusts various directions



Averaged 18. 7mpg hand computed for entire trip. Overhead said 18. 3mpg. My overhead has been around 0. 5 less than hand computed from day I bough truck.



On flat terrain I saw 19. 6-19. 8mpg... . on rolling hills in 16. 3mpg area... . in town 15. 2mpg.



OEM tires but running cruise control the whole way. No additives to fuel. Only mod is ROKKtech sensor.



Truck just turned 2500 miles on return trip.