Thursday, August 7, 2008

2006 Dodge 2500 Diesel fuel efficiency experiences

I have a 2006 Dodge 2500 (5.7) SLT 4 Wheel Drive extended cab short bed Diesel Pick Up truck (with no camper top) for my nursery and landscape business. When purchased new I got about 17 mpg. Concerned even then about fuel costs, I immediately put a K&N air filter system on and began getting over 18 mpg. It made the engine sound like a jet too... cool. I was happy with 18-19 mpg until prices started to rise dramatically in 2007. After seeing a spot on TV about hyper-mileing, I decided to give it a try, but less fanatically as the driver on the news segment was. My driving developed into what I call semi-hyper-mileing. Simply, I define that as: coasting to stops, never idling (if the truck is not moving, the engine is off), trying not to exceed 1500 rpm's while accelerating, and going the speed limit. This rose my mileage to about 22.5 mpg. These numbers were for city and highway driving. I did not see fluctuation. About this time I started to look into home brew bio diesel production. That was/is not feasible for me. First, I found restaurants charging for the old oils and often having contracts already established for the used oil with others, anyway. Then after learning the heating and explosive/flamable chemical needs in the process, I could see my liability insurance for my business going through the roof and my agent having a heart attack.... so home brew bio diesel was scratched of the list of possibilities.
Having given up on home made bio diesel I started to look elsewhere for some added miles, and having heard how additives were a waste of money, I was hesitant when I came across a website for diesel fuel additives. The product was Stanadyne Performance Formula Jr., and they claimed 8% increase, explaining lubricity as the reason for the success. I took a chance and was glad I did. After the second tank full I drove on the interstate at 70-75 mph for 3 hours and jumped up to 24.5 to 25 mpg. That mpg continued as I drove to and from work for the next two weeks. The daily drive for me is 7.5 miles in distance, with two traffic lights that usually catch me and speed limits that range from 25 to 55 mph. The cost is about $1.00 per 30 gal fill up in the 16 oz size by the case, and I feel I was saving approximately $12.00 per tank, or about $415.00 per year.
Trying to eek out even better mileage I decided to fill my tires up to at least the sidewall manufactures psi rating cold. I grew up being told to always fill tires to 5 lbs below sidewall rating, but after having taken a classic car to an open track event that mandated over filling of tire pressure, I felt fine with the extra psi's. This got me to 26 mpg. Having huge torque with this truck and being at 45,000 miles and soon to be in need of a new set of tires, I looked into a higher profile tire, but could not find a better one that came with it originally. I was told, however, that used tires get better fuel mileage than new tires due to the resistance factor being less on a used tire, so I decided to try and get another 5000 miles out of my current tires. I'll let you know when the new ones go on if they do indeed reduce the mileage.
Realizing it was going to be even tougher to squeak more out of a gallon, I bought an aftermarket mandrel bent exhaust system instead of the factory crimp bent system currently on it. I have yet to put that on, but at $285.00 - plus labor to install, I am going to have get a good improvement to make it worth the extra money. The jury is out on this investment at present. I'll advise when completed.
Not having yet given up on the warm and fuzzy bio diesel idea, I decided to try to find a petroleum distributor that might sell ready to burn bio in bulk. I called a few local suppliers and they said it was unavailable and not a good alternative anyway. Almost giving up I went to the Internet for one last google for a state wide search and found a supplier in Jax that recommended a supplier in Melbourne, who just happened to be pproviding the local school district buses with 100% bio diesel, and after a short discussion set me up with my own tank for my pick up and my company's fleet of diesel trucks and loaders.
We started out with B20 a week ago before we can go to ultimately desired B100, because the supplier said that we needed to run a tank or two of B20 through each vehicle to burn off the old petrol diesel sludge that would clog filters etc... if we went to the straight B100. I have run two tanks of the B20 through my truck so far. The first tank with the Stanadyne product still in it, and the mpg's stayed the same as with straight petrol diesel with the additive. The second tank I left out the Stanadyne, after speaking with the company's rep and she advised me that the lubricity of Bio diesel probably would not be improved by their product, and my leaving it in did not improve mileage any further either. That seemed to be the case, as the mpg's again remained the same without the additive. Since B20 is about 15 cents less per gallon than traditional petrol diesel I am saving significantly more that before. I am anxious to get the B100 and see how performance and mileage react. I notice no less performance with the B20. Besides the money, B100 is 30 cents less on average than petrol diesel, I feel good about burning a cleaner, renewable, and domestically produced diesel.
Just prior to going bio, I felt that wind resistance was key to getting better mileage, and decided to try a product called AirTabs ( and although I could have handled the Batmobile look they gave my truck if my mileage improved significantly, I was disappointed with my test drive, the same day I installed them, and I pulled them off fast enough, before they completely stuck to my paint, and transferred them to my car trailer. I did leave 12 on the roof. They looked kinda cool up there. I must admit that after pulling car the trailer before and after Air Tabs, the trailer did not sway on the road, as the manufacture claimed would occur, and although I promised myself a sway bar for the trailer, I do not feel I need one now.
I have two more ideas to implement in my search of a 30 mpg truck. The first continues the aerodynamic theme. I plan to put a thin sheet of something (PVC, Plastic, Aluminum... not sure yet), on the undercarriage to help the truck slip stream. And my local dealer is actually promoting a hydrogen generator system they will install for under $500.00. If 20% improvement is actually achievable, I will have my 30 mpg. The first systems I looked into were $1200.00 plus and hard to justify. Again, I will update as these additions are implemented and tested.
The following are my actual mpg findings with the B20.
1) Truck alone interstate driving:
a) 55 mph = 27.5 mpg
b) 65 mph = 25 mpg
c) 70 mph = 24 - 24.5 mpg
d) 75 mph = 22.9 - 23.5 mpg
e) 79 mph = 22.5 - 22.7 mpg
2) Truck alone in town = 24.5 - 26 mpg
3) Truck pulling loaded 20' classic car trailer:
a) 65 mph = 15.5 mpg (prior to any of my improvements, when I first got the truck, I pulled the same trailer with the same car and only got 11.5 - 12 mpg on the interstate doing 70 - 75 mph)
b) 70 mph = 14 mpg
c) city driving = 15 mpg
Recently I googled bio diesel decals, as I am now a proud user and want people to know, and found some really neat decals as well as factory looking chrome BIO DIESEL lettering and license plate frames. I put them on all my trucks and equipment.

Gary at GRNL

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