Off-road enthusiasts want to tune their street trucks for many reasons โ power and torque, driveability, fuel economy, towing performance or just to calibrate for upsized wheels and tires. For anyone wanting to drive off-road, a tuning device unlocks all of these benefits, and more. To find out more about how to boost the dirt performance of a Jeep, Bronco or trail-ready pickup, we spoke to Jacob White, Edge Product Manager.
First port of call for any would-be off-roader is a swap to an appropriate set of wheels and tires. Since this usually involves a change to the rolling circumference, the speedometer needs to be recalibrated to take account of the larger rubber.
Tuning devices from Edge Products and Superchips simplify the recalibration to a larger tire size. With the app-based Flashcal+, for instance, the Tire Size Wizard uses the phoneโs built-in GPS to determine your actual speed and the disparity between that figure and the speedometer reading. Itโs a highly accurate solution that automatically takes any difference between the tireโs marked size and true size into account.
Adjustments to the OE tire pressure monitoring system (TPMS) are the next logical step. โOwners may prefer to retain their factory TPMS sensors,โ says White. โWe give them the ability to suppress them so they can set the pressure lower. A Jeep Wrangler throws a warning light if you go below 22 psi. We canโt reprogram the system to a lower pressure threshold, but we can disable the TPMS sensors altogether so that when the owner goes rock crawling and is running at 9 psi air pressure, they donโt get the light. When theyโre done and they put the air back in for the drive home, they can re-enable the system.โ
For Jeep Wranglers and Gladiators, products offering tire-size recalibration and TPMS disablement include the Superchips Flashcal+, an entry-level handheld tuner, and the top-of-the-line TrailDash 3 โ an on-dash display thatโs loaded with performance programming. For Ford Broncos, the Flashcal is a great-value programmer that enables tire diameter changes and TPMS override.
Products like the Flashcal+ or the Edge EZX, an inline tuner for diesel pickups, give you the ability to adjust settings on the fly without having to reflash the ECM. You can disable TPMS when you get to the trailhead and re-enable it when you get back on the highway.
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Factory engine calibrations were developed for a wide range of driving conditions, in a factory vehicle. Once an owner makes modifications to that vehicle to elevate its ability at one specific driving style, like towing or off-roading, aftermarket tuning can be the key to getting the most out of what youโve built.
Tuners and programmers can unlock more performance on the trails through greater power and torque โ whether or not you choose to adopt an off-road preset.
โEngine control module (ECM) tuning can increase power and torque throughout the RPM range,โ says White. โFor owners who have gone to a larger, heavier tire-and-wheel package, that low-end torque can really make a difference in how well the vehicle performs on- and off-road.โ
Like the TPMS, engine tunes can be switched on the fly by devices like the Superchips Pulsar XT for the Bronco, providing the best of both worlds both on the trail โ including if the terrain changes โ and on the drives to and from the trailhead.
Tuning the transmission control module (TCM) is another great way to improve off-road performance. โWith a lot of these vehicles, the shift schedule will be different whether youโre in your regular drive mode or if you enter the vehicleโs tow-haul mode,โ White observes. โIn off-roading, you may not spend a lot of time at wide-open throttle, so it makes sense to lower the shift points accordingly.
โIt also makes sense to control when the converter locks. If youโre on the road, you might have to reach 55mph before the torque converter will lock. With our TCM strategies, that may drop to, say, 25mph, which will help to keep transmission fluid temperatures down when youโre off-roading. With that earlier converter lock, you also feel the much better power and torque transfer through the drivetrain. Youโll get more power at the wheels at a lower speed.โ
Of course, even devices like the Flashcal, which has no TCM tuning option, will enable you to recalibrate the speedometer to account for popular gear ratio and low-ratio transfer case adjustments, as well as disabling the sway bar in 2-Hi and 4-Hi ranges at up to 55mph for improved wheel travel at higher speeds than factory.
Tuners can also adjust the throttle response to make the driverโs life easier when off-roading. In Jeep tuning products like the Flashpaq and TrailDash 3, Superchips offers an off-road tune for Wrangler and Gladiator specifically with that in mind. The Off-Road, or Crawl tune better matches the engine and transmission power curves with an ideal throttle pedal feel to ensure low-speed, high-torque power transfer to the tires without the jumpy, touchy throttle feel you need to avoid on the rocks when in off-camber or rough conditions.
It also offers automatic changes in the braking so that the vehicle can hold itself, locking all four brakes when the vehicle is in park. โIn most cases the emergency brake only goes to one rear tire,โ says White. โIf youโre in an off-camber situation, itโs helpful that the tuning device can command all four brake calipers to engage, for better holding capacity at the tires. Thatโs also nice for guys in a winching situation to help hold the vehicle stable.โ
If youโre winching or running lights with a heavy amperage draw, some of the devices enable you to manually increase the engine idle speed. And in many applications there is also the option to manually engage the cooling fan at a lower temperature. This helps with slow-speed crawling if youโre not in a situation where the fan will kick in on its own, helping to avoid overheating issues before itโs too late.
On the TrailDash 3 and Flashcal+, the Crawl screen brings together features like the idle-speed adjustment with other off-road options such as activating the front and/or rear lockers in 4-Hi, extending the sub-25mph window for activated lockers to 55mph, and overriding the factory limitation on sway-bar control.
These tuning features are tested on the trails by enthusiast engineers. Each year, Superchips attends the Easter Jeep Safari and several Jeep Jamboree USA events โ not only for sales and marketing reasons, but also to develop and test new products.
โWe take our own fleet vehicles to those events and do product testing on the trail,โ White confirms. โAll of our devices are also thoroughly tested in the lab and on the street, but we know that there is no substitute for proving their capabilities in the same off-road environments where our customers will push them to the limit.โ
Weโve looked at many examples of how tuning can help off-road performance but before we finish, itโs worth noting that much of the same technology developed for Jeeps and Broncos can equally be applied to pickup trucks โ not just in off-road use, but in towing the rig to the trail.
For example, the Edge EZX for late-model Ram Cummins, GM Duramax, and Ford Power Stroke trucks offers adjustments to the fuel-rail and boost curves that improve drivability and make overtaking easier on the highway when youโre pulling a load. During testing, Edge even recorded 10% to 20% improvements in fuel mileage while towing.
When youโre not towing, the same TPMS adjustment technology used on the trail can be used on an HD pickup, too, enabling trucks like the F-350 to run tires lower than the 80-psi factory threshold to improve ride quality when unloaded.
