Gear Ratio Question

Gearing Up For Fuel Economy



Emissions technology utilizing compound turbos is designed to be most efficient at lower operating rpm than earlier single turbo engines.
Anymore, single turbo diesels are made more efficient with filtration and fueling controls in addition to emissions control devices not found in earlier models.
*they are efficient in pollution control, not that they burn less fuel per se*

 

Most of the product like that cannot be qualified as honest reviews, because of peoples actions changing based upon what they have done in addition to what it is they have actually done. I.e. if you enhance performance, you tend to drive it a lot harder because you can. If you put a new fuel saving device on, you tend to drive lighter on the pedal, and therefore numerical results are skewed anyway.

examples of this are too numerous to count. Even using control test data, differences tend to be minor in terms of actual savings.



Some performance parts absolutely have better operation than oem parts- not all do. Some fuel savers do as well.

mostly its whos behind the wheel.

 

A buddy with a 06 classic has same combo as you. (Former heavy haul truck) he swapped the 22.5 for 24.5 tire even with the higher rolling resistance it brought him up to high 5 from 4.5 us mpg running 68 mph mostly.

 

I have a Pittsburgh Power Box on a Series 60 and from “what I have been told” the power box is similar to a Bully Dog. I talked with both companies before I bought it. They market them as a slight fuel mileage increase, but I never noticed any. However the throttle response and power availability is worth every cent I paid for it and then some. I wouldn’t buy one unless you want more power as I doubt you will gain noticeable fuel economy unless you really baby it. You can do that without buying anything.

 

It has been almost 5 years so I don’t recall the specific prices. I “think” they were within a few hundred dollars of each other.

 

I'm not sure how much it would help you but another option would be to try to find a cut-off somewhere from a salvage yard.

If you could find the ratio you were looking for then you can either sell the rears that you have, or keep them in case you sell the whole truck.