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he only reason you want to hotrod your truck is to improve trailer towing performance, right?

The only reason you want to hotrod your truck is to improve trailer towing performance, right? Photo by Bruce W. Smith.

Unleash Power…Electronically

Engine programmers can quickly and effectively up your vehicle’s power output

“Chipped it yet?”

The diesel guys have been getting this question for years, but increasingly the owners of gasoline-powered vehicles are fielding the same question. There’s a wide array of performance chips, reflashers and modules available for nearly any automotive application you can imagine. Their purposes vary from firmer shifts to better gas mileage to extra horsepower, or all of these at once.

Most modern engines are controlled by a computer that references a variety of sensors and uses tables (maps) to determine proper fuel delivery and, in the case of gas engines, spark timing. The computers in factory tuned vehicles are programmed with a number of compromises between power, emissions, fuel economy, increased reliability and octane level flexibility. Not exactly what you want for hot rodding or towing.

It’s these computer programs and maps that aftermarket makers of performance enhancing re-programmers and modules manipulate to deliver more of what their customers want out of their vehicles.

With diesels it’s pretty straightforward. Computer controlled direct injection enables tuners to add fuel during the power stroke, which cyclically increases exhaust flow and turbo boost. Dyno testing showed we gained 100 hp and 150 ft/lbs of torque on my dad’s 2001 PowerStroke. With that much added power we beefed up the torque converter and added a trans command to protect the transmission.

The Performance Management Tool from Bully Dog. Photo by Bruce W. Smith.

Gasoline powered engines realize only modest power gains with these products alone. Advancing the spark timing and leaning the fuel mixture can provide both horsepower and fuel economy gains. You can even pinpoint where you want the changes to be made in the rpm range.

I use a reflash program to make changes on my gas-powered car to regulate the correct air fuel ratios, adjust timing and change rev limiters. I use the reflash in conjunction with a boost controller module to change and monitor boost levels.

Producers of aftermarket electronics use a variety of methods for changing the signals the Engine Control Unit (ECU) is sending. One of the early methods was to replace a computer chip within the ECU to change the mapping, hence the nickname “chip”. The downside of the chip is the physical interaction with the inner-workings of the computer itself.

A second type of electronic enhancer is the piggyback-style unit, which doesn’t change the mapping of the ECU itself, but instead intercepts the signals between the engine sensors and the ECU and replaces them with different signals to gain the desired outcome. These types of units can be installed inline between factory plug connections, or they can be hardwired.

With the implementation of a standardized ECU interface called On Board Diagnostic 2 (OBD2), emission levels could be easily monitored by an off-vehicle computer. The OBD2 also opened the door to other computer-related applications for general auto maintenance and performance enhancement.

Through this simple plug-in interface came the ability to monitor nearly every sensor on the vehicle, and the ability to adjust and even reflash (re-program) various onboard maps and parameters.

So what works and what doesn’t? There’s no doubt that you can realize tremendous power gains on turbocharged diesel trucks by using these chips and programmers alone. The best results for gas engines, however, come with a combination of intake, exhaust and programming. Unlocking the extra power and fuel mileage from your late-model vehicle is only getting easier and easier with an amazing selection of features, so do some homework and find out which one offers just what you need.

—Larry Walton