Hi PAK77. Welcome to the forum. I have a friend with a '99 and an '06. Both are Dodge dually diesel 4wd 3500s. He has had the '99 chipped for a couple of years. He was pulling a three-car trailer before the modification with no problems. After he added the box, he tore up the transmission within a few months. Keep in mind the truck already had over 200,000 miles on it and the transmission was original. When he replaced it, he installed a special torque converter.
Both trucks were wrecks that he rebuilt. The '06 was hit so hard in the front, it pushed the engine back over a foot, bent the frame, and mangled the firewall. I added a box to that one before we ever started the engine. After the most astonishing test drive and an inspection by a local injection shop, it was discovered the truck already had oversize injectors and an oversize turbo. The estimate is it is developing between 600 and 700 horsepower and I forgot how much torque. I got a ride in a Viper once. This truck feels the same! It has a six speed transmission and it will slip the clutch under the right conditions.
16 mpg seems kind of low. We used the '99 truck to haul a car from Wisconsin to Texas and to haul back a paint booth that weighed at least twice as much. Fuel mileage was measured in miles per tank instead of miles per gallon and I can tell you the mileage dropped off a lot when I was driving because I had to be back home in a hurry. My friend says he averages around 22 - 24 mpg when he drives 65 mph. On the trip, I was driving around, ... Uhh humm! No one was passing me, even going up hills with that load. As I recall, we were getting around 150 miles per tank less when I was driving.
There are some things to consider. First of all, check for an injection specialty shop in your area. The one in my town does something with a spring in the injector pump, among other things. It results in more power, much better fuel mileage, and an end to any black smoke from the tail pipe. I don't know what the effect is on emissions, but the modifications are approved by Chrysler for trucks still under warranty. The injection company is considered a subcontractor. You might want to see if you can get your mileage up to closer to 20 mpg before you add the box.
The other thing to be aware of is if you have the overhead computer that displays miles per gallon, the reading will not be correct. While it's true fuel mileage will go up, it won't be as high as the display shows. The traveler computer calculates the miles per gallon from engine rpm and injector pulse width. The box changes some of the sensor readings that the engine computer receives and that affects the traveler computer's calculations.
Logic says these boxes can't really work. Diesel engines are wide open to air; there is no throttle blade. Engine speed and power are controlled solely by how long the injectors are held open. You would think just pressing the accelerator pedal further would do the same thing but there's no denying they do what they say they do.
I'm only familiar with two versions of these boxes. The older truck has three settings on the box. You pick one and leave it alone. The box on the newer truck has a controller that mounts on the dash. You can make adjustments and view all kinds of data while driving.
Tuesday, August 10th, 2010 AT 4:04 AM