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Discussion Starter · #1 · (Edited)
After participating in a discussion, Not so Cheap Air Box Mod V3 started by @steve05ram360 and tips and encouragement from @'04CDT, I'm posting my recent trip from Birmingham, AL to Flanagan, IL.

Before leaving I taped the lower section of the front grill with a small hole to allow restricted air flow to the lower cooling system. Also applied tap to the gap between the cab and bed and taped the rear bumper that extends past the bed. See pics. I did a 2 test drives with the reduced air across the cooling system and cut a small opening in the front. I watched my gauges and A/C cooing. Also, MMX has a rad fan PID. The rad fan never cycled on the trip. Trans stayed between 175 and 180. A/C was ice cold, ran on low fan speed.

Trip to Flanagan, IL with stop in Mitchel, IN. I logged ambient weather/engine hours/odometer/Overhead (LOM) and number of stops as I drove. Worth noting, about 100 miles to Mitchel, IN was on hilly, curvy, 2 lane county roads. With the load it impacted my mileage.

Also worth noting, as I drove north, ambient temps dropped, IAT dropped and LOM dropped from 30.8 MPH to 30.2 MPG. The roads at this point were straight and gently rolling hills.

When on best MPG 3 injector pulse vs. single pulse, LOM MPG dropped. I've driven with 12V, single injector pulse, well over 150K. It always gets better mileage on a 12v valve tune.

Side Note: intuitively, Single Injector Events, reduce the number of injector events by 66% increases the life of the injectors. My OE injectors have +145K and all indications they are in good shape.

Overhead, LOM, was about 5 MPH higher than hand calculated.
Handwriting Font Paper Paper product Writing



First fill up was 60 miles of my destination. Hand calculated was 23.6 MPG.

Return Trip: No load in the truck. Rode much rougher, accelerated much quicker, cornered so much better. I filled up in Birmingham, AL. 25.6 MPG.

LOM continued to rise as temperature increased except the last 100 miles. They dropped about 0.5 MPG. When I got home, I noticed half of the front bumper tape and folded in, allowing air into the grill area.

Other notes, 23 engine hours, averaged 57 MPH driving. lowest ambient 68F, highest 85F. Engine 1840 RPM at 65 MPH.

Conclusions:
The following improved mileage: Aero mods, intentional driving, 65 MPH. IAT impacts mileage. 700 pounds and some curvy, hilly county roads reduced mileage by 2 MPG.

24.4 MPG trip average. Fuel cost $289.52

At 70 to 75 MPH the truck go 20 MPG. At todays fuel prices that would have cost $64.00 more in fuel and reduced my trip time by 3.5 hours. Each individual has their on pain points on fuel cost and time.

Reduced speed has proven to have less wear and tear on tires/brakes/suspension and generally safer.

MY 2006, 2500 SB, RWD, mods to improve handling, MPG and reliability:

Turbo Blanket
New, Wix, air filter, stock air box has some extra holes in the bottom
Tonneau cover
Tight suspension including: Fresh shocks, urethane bushings replacing all front end and leaf springs, rear anti roll bar, new ball joints, new U joint on steering column
2nd Gen, ported, air horn and deleted grid heater
Cummins T Stat
Replace ALL engine and fuel management sensors and relief valves
10W40 oil vs. 30W40
Taped lower front "grill" opening, air gap between cab and bed, rear bumper
12 Valve street tune, MM3, Rob
Fuel additives, 8 oz 2 SO, 8 oz ATF per 30 gallons
Single disk torque converter, performance valve body, shift pressures increased via tune

Automotive parking light Tire Car Wheel Vehicle
Tire Wheel Car Vehicle Automotive tire
Automotive tire Hood Road surface Automotive lighting Asphalt
 

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Awesome writeup, congrats on the sucess!!

Your tape all the way down the bed, can go either way, half seal down to the body line or tape the bumper. I suspect you may have been able to do better if only taping half way to body line, reason being is the flow separation does not occur just in front of the tire on the bed and you end up with drag from air flow going right into the tire. Would need to test to be sure.
 

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Man 25+ mpg over 600 miles is awesome. The best i have managed is the 25 in the sig but just 1 time and i milked every hill i could over the 200 miles on that tank. Warm day, warmer IATs and low speeds...
 

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Discussion Starter · #4 · (Edited)
Man 25+ mpg over 600 miles is awesome. The best i have managed is the 25 in the sig but just 1 time and i milked every hill i could over the 200 miles on that tank. Warm day, warmer IATs and low speeds...
Some differences:
RWD vs.4WD
12V, single injection per cycle tune
Stock injectors/turbo, maybe, maybe not
Front grill blanked off
Tire size and type
Heater Grid
06 is better looking than 05 - :ROFLMAO:
 

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If I unplug two injectors, will it be a Cummins?
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You can buy a 2017 Duramax 2wd and hope to get 16 mpg on the highway. But I suspect you like yours better. Good job.
 

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Discussion Starter · #6 ·
You can buy a 2017 Duramax 2wd and hope to get 16 mpg on the highway. But I suspect you like yours better. Good job.
Sometimes it's better to stick with the Devil you know rather the Devil you don't know.

16 MPG highway, I'd park it or Cummins swap....o_O
 

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If I unplug two injectors, will it be a Cummins?
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Sometimes it's better to stick with the Devil you know rather the Devil you don't know.

16 MPG highway, I'd park it or Cummins swap....o_O
I had to get rid of the 2018 g56 for an auto last summer for full time RVing, since my wife doesn’t do manual. That one for 22-23 highway. Not bad for a 4x4 on 35’s. This one drives really nice, but it loves the taste of diesel.
 

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I had to get rid of the 2018 g56 for an auto last summer for full time RVing, since my wife doesn’t do manual. That one for 22-23 highway. Not bad for a 4x4 on 35’s. This one drives really nice, but it loves the taste of diesel.
Probably would have been cheaper in the long run to have sent her to a driving school.
Then she'd be even more perfect than what she currently is. (y)
 

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Discussion Starter · #10 ·
OP. Great mileage. (y) Well done for that speed.
I've never gotten close to those numbers.
For now I'm used to my all around eighteen mpg.
Thanks
 

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I was just looking on Google to see air dam improvements and stumbled on this.
I wouldn't read two dozen pages on this subject, but you might like to.
 

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Discussion Starter · #13 ·
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If I unplug two injectors, will it be a Cummins?
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OP. Great mileage. (y) Well done for that speed.
I've never gotten close to those numbers.
For now I'm used to my all around eighteen mpg.
I had a 1996 2 wheel drive that could get 26.5 mpg all day if I did 64 mph. When I hit 70, not only did the truck get much louder but it also suck more fuel. That was my only Cummins auto. My 12 valve manuals would only get 22 mpg at best.
 
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2004 2500 555/5600 RWD QC/LB
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24+ MPG True

Great numbers!!

At exact 1,300-miles:

— 56.5-mph reflects reality pretty well (23-hours).

— 62-mph would have been the Average for doing 70 (if all Interstate; so 21-hrs)

— The “time savings” would have been under three hours as traffic volume interference increases the gap between Set Speed and Average Speed. It’s not just the aero penalty either:

A). Pull Out to Pass Penalty
B). Brake for Slower Penalty
C). Steering Penalty
D). RPM Penalty

— Steer more, change throttle opening more, use brakes more. Each adds to the aero penalty. And the above 1,900-rpm factor would also be at work. (Pull out to Pass is mental/emotional energy; gets one run down earlier in the day).

Two hour change is likelier. Over three is unlikely.

1,300-miles in (2) days is a fair truck driver test (seat cushion, hmmm) as it’s stretching the limits for the energy & awareness necessary to keep safe practice at highest level through a long day.

Perspective: we all do well to the 400-mile mark given adequate preparation. Past that is where White Line Fever sets in and our Reaction Time & Distance are worse. Everyone gets sloppy. (No exceptions).

MPG goes down during the day where all else is the same.

Q: How does one counter this?

A: Leaving earlier to spend less time in higher volume traffic as being alone is success marker for safe operation plus highest MPG. Truck and operator expend less energy.

If in a big truck given your 57-mph EH, “travel time” would be dead-on 13-hours with a 50-MPH Dispatch Estimate (0230 Departure) to have bought fuel at 1730.

1). Departure Time is crucial.
2). Timing of meals & breaks, same.
Energy to get in those last 250-miles is key.

— With respect, I doubt you left before 0430. Had you done so, the Average MPH would’ve been a bit higher given mainly Interstate. And a few tenths to the MPG. Don’t think this any kind of criticism, it’s to help you or anyone to think about a trip plan.

I’d say you’re feeling pretty darned good about bringing the CTD back up to par with the maintenance (some needed; some you got ahead on), the TLC (gap-covers), and the discipline to allow the CTD to do its best. Congratulations!

Debrief:
— The poly leaf spring-eye bushings are obviously a penalty when empty. Rubber (literally) absorbs vibration.

A). The counter is tire pressure where one doesn’t get below the Dodge Minimum (50-psi on my ‘04 RWD door placard). 50 is above the Load & Pressure Table Minimum (substantially).

— Second part is shock absorber design. I’d rather have a set of KONI on yours than BILSTEIN.

B). Higher than 55-psi (given scale weight confirms placarded use) won’t add enough to MPG to put up with a harsher ride, and that braking/handling/steering is about ideal (as is even tire wear).

The Ace:
PURPLE Ultimate Seat Cushion ($120-$150).

1). Can’t wear it out.
2). Eliminates all the cracks in the road.
3). Alertness seriously extended (no squirming around in seat, leaning towards one side or another to “get comfortable”).

(Shown without cover). Note recess for tailbone)

Automotive lighting Purple Hood Rectangle Building


How good is it? I’m pretty sure I couldn’t drive a truck all day without it. (Old injury plus age-related health). And, at 6’2”, 200-lbs and in constant use since 2016 or so . . it won’t wear out. (I also use their Lumbar Cushion. Baby, I float on that seat!).

Truck drivers sit on air-ride seats in an air-ride cab on an air-ride suspension. My CTD is a more punishing ride at the end of a long day.

— Takes about a day to get used to it. Seat has to be re-adjusted to get best results besides ideal posture. Loose full-cut clothing, wallet in shirt, and knee-high compression socks.

Drive Wear lense sunglasses (prescription)


Summation:
— If that trip were to be run again, loading the CTD bed to about 1,000-lbs including the delivery item would give several hundred pounds on return trip to help with vibration-induced fatigue (given that FF/RR tires are at scaled safe minimum). And Ultimate Cushion (plus better posture, etc).

Best rest breaks & food stops plan is much easier when running a route the second time.

Experience Says:
— My trip-planning 24-MPG isn’t changed by up to 1,000-lbs as tested over a 47,000-mile stretch of flat terrain (but did include having to transit Houston every 350-miles).

At 1,200-lb bed load I could record the minor Gulf Coast difference. (Which would be magnified by hilly terrain).
Two-hundred pounds would be a minimum, 3-400 preferable, IMO.

.
 

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I really need to get a 12v tune. Currently, the truck has EFI live by Firepunk and has their standard 5 tunes. However, they said they could replace one of the tunes with a 12v tune if I took it up there. They claim that their testing has shown no difference in mileage, which is fine because my main reason would be to make the injectors last longer. I know my truck won’t ever get near what you guys are doing since it’s lifted on 35s but I’d like to try to get more than the 15 or so it currently gets. I’m hoping to see an increase with summer weather and fuel. I’d like to get working on replacing the engine sensors too.
 

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I really need to get a 12v tune. Currently, the truck has EFI live by Firepunk and has their standard 5 tunes. However, they said they could replace one of the tunes with a 12v tune if I took it up there. They claim that their testing has shown no difference in mileage, which is fine because my main reason would be to make the injectors last longer. I know my truck won’t ever get near what you guys are doing since it’s lifted on 35s but I’d like to try to get more than the 15 or so it currently gets. I’m hoping to see an increase with summer weather and fuel. I’d like to get working on replacing the engine sensors too.
After chucking a 24v I cherish the quieter,smoother '07 I have. I heard a 12v tune the other day and it reminded my of my old '98.5.
 
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If you have an HO '04 you have the most efficient 5.9 CR ever made.
The early 2003 250-HP engines are better for top MPG when solo (some were NV-4500, had to have NV-5600).

But, loaded and/or towing the 305/555 engine has the overall advantage. The power bump is really the fine-tune HPCR got after field reports made clear that the sweet spot needed help (my belief).

.
 
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