What kind of MPG gains can I expect with tuning?
In a best case scenario we see common rail diesel engines pick up 2-4 MPGs after tuning. This would be driving around 60 MPH, on flat ground, with a tail wind, at sea level, in a truck with perfect health, and stock tires. When you can use the added power from custom tuning to run a higher gear you’ll be using less RPM to do the same job. Reasonable drivers often report 2-3 MPG gains in unloaded, mixed driving scenarios.
These Modifications Kill MPG
Big tires, heavy bumpers, and excessive lifts are often the culprit to unreasonably poor fuel mileage. If you don’t have those problems, often a boost leak within the charged air system can cause excessive smoke and bad MPGs.
The bigger and heavier your wheel and tire combo are, the worse your fuel economy will be. The added rotational mass requires more fuel to produce the same power. 35” tires on a reasonable rim seem to be the limit before a steep cliff in efficiency.
You will never get the same MPG while towing as you will unloaded. The weight and wind drag created by your trailer, and health of the truck make a big impact on MPGs. The best strategy to improve your towing MPGs with tuning is taking advantage of “Shift Up, Throttle Back”. The added power and wider torque curve is there to find a speed that allows you run a higher gear than usual, thereby using less RPM/Fuel to do the same job.
If you cruise at 90 MPH on the highway there isn’t much that can help you on fuel mileage. We have documented our biggest gains in efficiency on 2 lane highways doing around 60 MPH. The extra power from custom tuning will give you the get-up-and-go you want when you need to pass someone and take advantage of a more responsive throttle pedal when you need it.
Your transmission computer (TCM) calibration is based on the expectation of stock torque outputs and throttle pedal inputs. Upgrading to custom TCM Tuning from Calibrated Power means matching your TCM tune to your ECM tune. This prevents clunky shifts and hunting for gears, which cost you MPGs, and massively improves your driving experience.
How to improve MPGs
Make sure your truck is in sound mechanical shape. Include a boost test to your maintenance schedule. Avoid modifications the drain efficiency. Use custom tuning from Calibrated Power as a part of a “Shift Up, Throttle Back” strategy.
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