Tweaking the vehicle computer for better mileage

I'm very much of the opinion that sophisticated computer engine controls and more precise hardware such as high-pressure fuel injectors are the key to short-term fuel-economy improvements in current gas engines. Other drastic measures such as small-displacement, turbocharged engines will require more involved engineering, and there's still a future for exotic measures such as HCCI and even plasma combustion. But I spoke with two calibration engineers at SEMA who help develop aftermarket tuning controllers that work with the vehicle's ECU. In the past their jobs focused solely on improving power but both say they're busy with mileage calibrations now. However, tweaking the vehicle's computer requires an in-depth knowledge of programming. Manufacturers have teams of engineers working on these programs, and while making changes is easy, the results may not always be satisfactory.

Ron Bilyeu is an independent tuner working out of Indiana-based Pro Dyno Tech. Working with a chassis dyno that measures torque at the drive wheels, Bilyeu says he can improve fuel economy from 15 to 20 percent. I don't doubt those improvements are possible with many vehicles, especially those with older engines, but not all vehicles will enjoy such gains. I am impressed with Bilyeu's credentials and commitment to understanding and teaching of engine programming. He has instructional tapes sponsored by Snap-On and appears to treat each vehicle as an individual project instead of developing a universal program. I would take my car to him, if only to find out how much it pulls on the dyno.

[Source: Denise Hinckley /]

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