Inline tuning modules have become increasingly popular in recent years, especially for late-model trucks. Unlike flash tuning, an inline tuning module makes changes to the vehicle’s powertrain control module (PCM) or engine calibrations without modifying the PCM. Inline modules plug directly into the most important engine sensors and change the signal between the PCM and the engine or the sensor, manipulating the output without making changes within the PCM itself.

This method of tuning has become vital since OEMs started changing over to encrypted or ‘locked’ PCMs, which made flash tuning much more challenging. The additional security in late-model vehicles has made those control modules harder to crack for producing a flash tune. This process might take two or three years for a flash tuner, whereas the reverse-engineering and development process for an inline tuner is less complicated. As a result, inline tuning modules can typically reach the market within 12 months of a new vehicle being launched and still offer most of the benefits of flash tuners.

Benefits of inline tuners

Inline tuners offer improved performance through an easy, plug-and-play installation that doesn’t make changes to the vehicle’s standard components. Any changes are quickly reversible and undetectable to a dealer if the truck needs to go in for warranty work, providing peace of mind for the consumer. The upgrade is simpler, faster, and more flexible than a PCM swap.

The Edge EZ Tuner and latest EZX modules, Superchips Pulsar, Pulsar LT and Pulsar XT, and the Juice with Attitude are examples of effective inline tuning devices that offer impressive capabilities and reliability at lower cost than a traditional flash tuner.

Benefits such as drivability improvements, power gains, pedal lag elimination, and increased fuel mileage are popular with customers who choose an inline tuner – often, customers for whom the OEM-standard power level is already enough. If available, flash tuners offer additional power to those who want it. But in the absence of an unlocked PCM, an inline module like the Pulsar XT for the ’21-and-newer Ford F-150 EcoBoost can offer immediate benefits to advanced users who usually favor flash tuning, including as much as 65-horsepower to the tires, until a flash option becomes available.

“There are other benefits to the inline approach, including the ability to adjust tuning levels on the fly,” explains Jacob White, Edge product manager. “With many of our devices, you can adjust what it’s doing while you’re driving down the road and see real-time changes in power output or pedal response. That’s not possible with flash tuning, where you must generally shut the vehicle off before changing the program.”

The ability to make inline tuning adjustments through steering-wheel controls or via an app is also an accessible, intuitive approach for customers who aren’t mechanically or electronically minded. App-based inline tuners like the Edge EZX also make it simple to implement the very latest tunes, features and functions, which are pushed automatically as upgrades to the phone app, ready to be applied to the vehicle.

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History of inline tuners

Inline tuning modules are riding a wave of popularity right now, but the concept isn’t new. “A lot of early attempts at electronic tuning used the inline approach because people didn’t always know how to access the control computers,” notes White. “Diesels were an obvious market. For more than 20 years now, there have been pressure boxes that you can plug into the fuel-rail sensor to add 50 or 100 horsepower to a diesel truck.”

But early attempts at bypassing the PCM didn’t always make safe power.

“The big difference from the old ones to now is the level of engineering, development, and testing that goes into the latest modules,” he continues. “We’re not just doing a pressure box. We’re monitoring exhaust gas temperatures, fuel volumes, and the vehicle output, making sure that everything stays within a safe level before we apply our changes.”

That thorough approach to Edge and Superchips’ product development extends to emissions performance as well. Each one of the brands’ inline devices either has a CARB EO compliance document, or the company’s engineers have done self-certification to ensure that it will pass CARB evaluation when tested.

“We make sure that our devices develop safe and usable power that’s not going to cause emissions concerns,” says White. “That’s not something all our competitors can say. We’ve tested one of our top inline competitors in the late-model GM diesel space and their box only plugs into one sensor under the hood, for fuel-rail pressure. By only changing the fuel-rail pressure, they aren’t taking into account how that extra fuel affects emissions – they’re not making any changes to the airflow demands or commands from the vehicle. Our devices tap into as many places as necessary to make sure calibration changes can be done safely, so that for example if the rail pressure gets too high, the vehicle can pull back to the safety of the factory calibrations if it needs to.”

Inline tuning for more than just power

Part of the sales success of inline tuning modules in recent years has been driven by the breadth of features they offer. Smartphone apps provide easy control for features such as calibrating for a new tire size or disabling auto start-stop systems – benefits that were traditionally confined to more expensive and intrusive flash tuning.

“It’s not just about increasing horsepower anymore,” White confirms. “Many owners of the newest vehicles on the market, especially on the diesel side, aren’t necessarily asking for more power. The trucks come with enough from the OEM, so their owners are content – they can pull their trailer or tow their camper as fast as they want to go, for example. But we can tailor the driving experience to their specific needs a little easier than we can with a full flash. We can improve drivability and eliminate throttle lag. With the Edge EZX module for Cummins diesels, drivers can maximize turbo and engine life by setting a timer to let it cool down after a demanding drive.”

That attractive list of features comes with an easy, 20-30-minute install and a sub-$600 price point that stacks up well against more expensive flash tunes or the need to buy multiple competing devices to match the functionality.

Of course, some truck enthusiasts still prefer flash tuning, for its potential to yield bigger power gains than inline tuning can offer. Edge and Superchips are happy to continue supporting that market, too. Some owners even choose to stack a flash tune and an inline device, using the inline module to boost power further after pre-loading their PCM with a lower or mid-level flash tune. There are Pulsar XT customers, for example, running the device on top of their Bronco’s Ford Performance flash chip.

Whatever the application, drivers have the reassurance that inline modules have built-in safety parameters, such as not changing the calibration until the engine is up to operating temperature. “We put a lot of engineering effort into making sure these devices are smart enough to do in the field what they are designed to do. The vehicle has the technology. We want to make sure our products have the technology to keep up with it.”

Shop Edge and Superchips inline tuning modules now

Shop Edge and Superchips inline tuning modules now