Can an engine tuner (chip, module or programmer) improve the performance of your diesel pickup truck? The short answer is “yes,’’ but a longer explanation is in order.

While manufacturers of aftermarket performance products claim tuners can add 3-4 mpg, the actual savings, if any, largely depends on how and where you drive. By definition, performance products are designed to increase engine output. For example, a plug-and-play Juice Attitude CS programmer from Edge is purported to add 150 hp and 360 ft-lbs of torque (not recommended for stock vehicles) to a Dodge Ram 2500 with a 6.7L Cummins engine.

That’s sweet for smoking Corvettes off the line, but it won’t save you money at the pump. In fact, the added horsepower can make it difficult to keep your foot off the pedal, leading to increased engine wear and stress on your transmission and drivetrain. Simply put – you risk shortening the lifespan of your truck, voiding the manufacturer’s warranty and the likelihood of being pulled over by the highway patrol.

On the other hand, if you tow heavy equipment, climb hilly terrain or travel long distances, an engine tuner could be your best friend.

CUSTOM PERFORMANCE

To make sure you’re on your best behavior, manufacturers such as Edge and Bully Dog provide a Mileage Coach to help you gauge, monitor and conserve fuel consumption.

Bully Dog also makes digital watchdog gauges for Caterpillar, Cummins, Detroit, Mercedes and Paccar engines that include speed limiter adjustments, diagnostic reader and driving coach, as well as an ECM tuner that includes economy tuning, economy/power tuning and custom tuning. Designed for fleet owners, the ECM tuner for Caterpillar promises a 15 to 18 percent power increase and 6 to 12 percent gains in
fuel mileage.

The beauty of an engine tuner is it enables you to customize your truck – from towing to off-road racing, often by toggling a switch or tapping a touch screen.

The Edge Juice, for example, lets you choose from six on-the-fly power levels (25 hp, 70 ft-lbs; 40 hp, 90 ft-lbs; 50 hp, 120 ft-lbs; 65 hp, 160 ft-lbs; 80 hp, 200 ft-lbs; and 150 hp, 360 ft-lbs), as well as a stock (level 0) setting when needed. It comes with a 4.3-inch touch screen with optional backup camera capability for easy trailer hookup.

Another plug-and-play product, the Stryker Injector Duration module by TS Performance promises up to an additional 135 hp and 200 ft-lbs of torque and gains of 3-4 mpg.

As the name implies, engine tuners adjust your vehicle’s computer settings, such as injection timing, fuel/rail pressure and injector pulse width for optimal performance.

Depending on the bells and whistles you choose, engine tuners can range in price from an average of about $350 to several thousand dollars for Class 8 truck versions.

THE GOOD AND THE BAD

Jason Maki, owner of K & S Service Center in Weston, Wisconsin, carries a full line of diesel engine performance products, including Edge, Bully Dog and H & S Performance.

“All of them do different things,” he says. “You get a little better performance, a little better efficiency and a little better economy. And that’s what most people are looking for.

“Back in the late ’90s, early 2000s, diesel performance was really a huge market,” Maki says. “Guys with just a programmer or a module or chip could get 50, 80, 100, 140 horses out of their pickup. But when you get up to those higher horsepower levels, you’ve got issues.

“For the guys just looking for economy, you usually don’t see a problem, but for the guys who want big power, you end up needing to do extra work on the engine and transmission.”

Maki says stricter emission standards, such as the use of urea and diesel particulate filters, have decreased the demand for performance products in recent years, even though today’s tuners are compatible with modern diesel emission systems. Keep in mind, though, that removing an emission system is illegal, unless for off-road use.

Maki has an engine tuner in his 2014 Dodge Ram 2500 with 6.7L engine, primarily for added economy, and says even with today’s stricter emission standards, performance programmers can add a few miles per gallon and about 50 hp.

Still, with today’s lower fuel prices, is it really worth spending $350 for a slight gain in fuel economy?

BENEFITS TO SOME DRIVERS

“It depends what you’re doing,” he says. “If you’re just running around town, probably not. But if you put some miles on, if you’re traveling for work, then these devices can help you. If you gain 2 mpg and you’re putting 500,000 miles on, it definitely adds up.”

A Cummins dealer, Maki advises truck owners that installing an engine tuner could void the manufacturer’s warranty.

“We let them make that choice,” he says. “But once they’re out of warranty, the sky’s the limit.”

Most engine tuners plug into the vehicle’s onboard diagnostics port under the driver’s side of the dash and have a cable that can be run up the door seal to a window-mounted monitor. Installation takes about 15 minutes.

Tuners can be used for engine diagnostics, performance testing and speedometer calibration when changing tire size. They’re also updatable over the Internet.

When shopping for an engine tuner, Maki recommends talking to a local dealer before purchasing online. 

“You can find these all over the Internet, of course,” he says. “Us brick-and-mortar businesses have a hard time beating the prices, but what we like to do is have people come into us so we can help educate them so they can get into the product they need: What are you trying to do with this truck? Are you doing towing? Are you looking for economy? And if they ever have issues, we’re here to answer questions. That’s something you won’t always find on the Internet.”