Tuners are tuners are tuners, right? They are all the same. Wrong. All will give your rig a little more ooomph–a good kick in the pants–but the more sophisticated tuners will also give you some special features. What we mean by that is a better-than-average tuner not only boosts power and adjusts transmission shift points, but also helps control other aspects of your vehicle that make it handy on the trail.

One such product is the Bully Dog GT Tuner for Jeeps. It’s currently available for ’06 to ’13 Grand Cherokees, ’06 to ’10 Commanders, and ’07 to ’14 Wranglers, offers easy physical installation, although you must have access to a computer, and provides power gains along with fuel economy through its Driving Coach feature. The Driving Coach is a graphic representation of your driving efficiency, delivering a number of parameters, including a grade, providing instant feedback on driving habits, helping you conserve fuel.

The Bully Dog GT Tuner kit included the GT Head Unit, power cable, adapter plug cable, universal mount, HDMI cable and mini USB cable (seen bundled together). The SD card, card reader, fuse spade, and fuse tap (not seen) were also part of the kit.

In addition, the Bully Dog GT Tuner offers special operations in the Jeep such as punching up the idle temporarily without resting a foot on the gas pedal when running a winch, turning off the engine fan for fording deep water, turning on and off electronic lockers in the axles (if available), controlling electronic-disconnect anti-sway bars (if available), changing transmission shift points (automatic trans), speedometer correction for tire size and gear ratio changes, and the control of lights and other similar vehicle operations.

“Almost everything on the Wrangler is computer-controlled. Our goal was to offer more power through engine tuning; and allow the user to modify settings on the vehicle such as axle lockers, idle speed, traction control, tire size, and axle ratio.” Kendal Yung at Bully Dog continued, “You can also pull up and read trouble codes using the GT Tuner.”

Uploading the Tuner

This installation begins at a computer. We sat down in front of a PC (Mac software is also available for uploading the Bully Dog GT Tuner) outside of the vehicle, and opened up the Bully Dog Update Agent app. That can be found at www.BullyDog.com/updateagent.php. The file must be installed on your computer first.

After the updated file is installed to the computer, it can be transferred to the GT Tuner through a number of steps that must be followed carefully. For these program updates, you will need the GT Tuner, memory card, card reader, and the kit included USB cable.

This installation began (after carefully reading the instructions) at a desk in front of a computer updating the software in the Bully Dog Tuner GT.

Get It Wired

The next big step is to locate the OBDII port in your vehicle. On most Jeep Wranglers it is under the front console and to the left of the steering wheel column. There is an adapter plug cable included in the Bully Dog GT Tuner kit that has an HDMI/power plug adapter on one end and an OBDII adapter plug on the other. Connect the OBDII adapter plug to the OBDII port to begin the process.

If you’re going to do a permanent connection (and we recommend that you do), the next step is to connect the power cable. In order to do that, you must locate an ignition fuse. An ignition fuse is one that is controlled by the position of the key. Sometimes this is called a “key-on” or “key-off ” fuse. The one that controls the front windshield wiper can be a good choice, but any fuse that turns off when the key is turned off will work just fine.

We ran the power cable from the fuse box, through the firewall to the interior compartment near the driver’s door. At this time we also installed the adapter plug cable. It was necessary to temporarily remove the panel on the side of the dash console near the driver’s door to hide the HDMI/power cable end of the adapter cable and connect the power cable to the adapter cable.

The OBDII plug on the adapter cable was connected to the Jeep’s ODBII port.

The HDMI cable was also connected to the adapter cable, and the HDMI cable strung up the driver’s A-pillar to where we planned on mounting the Bully Dog GT Tuner for the Jeep. At this time the switch on the adapter plug was turned to the “battery” (BATT) position.

There are a number of mounting options for the GT Tuner available through Bully Dog, but the one we liked best and that comes with the kit, is the Universal Windshield Mount. It’s a sturdy, yet flexible stalk mount that is adjustable and easy to attach to the windshield.

Using the suction cup on one end, we securely placed it near the driver’s side A-pillar and just a few inches above the steering wheel. This kept the GT Tuner out of the way, yet easy to see and use. Through the T- shaped socket on the GT Tuner’s back, it was just as easily mounted to the square-shaped end of the Universal Windshield Mount. The tuner was then connected to its HDMI cable.

Some Important Prep Steps

There are a few important steps prior to beginning the upload to the vehicle. Make sure you have enough time, you need at least one full hour. Always perform uploads in a location where there is phone and internet access since Bully Dog technical assistance is only available 8 a.m. to 5 p.m Mountain Standard Time, Monday through Friday. In addition, complete a successful update to the GT Tuner prior to the installation.

Bully Dog also recommends all factory installed electronics be turned off inside the vehicle. This includes things such as headlights, heater, air conditioning, stereo, DVD players, etc. Failing to do so may prevent a successful upload.

As well, any other electrical accessories such as chargers, trailer brakes, alarm, CB, lights (any electrical devices installed after the vehicle was released from the factory. You don’t have to uninstall them; just make sure they are not getting power) should be disconnected from the fuse box. Also make sure your battery is fully charged, you sure don’t want the battery going dead in the middle of this installation.

Uploading The Jeep

Once the GT Tuner was powered up, it went through initialization, and eventually the Main Menu appeared, at which point we began the program download process.

Once we had done all that we were ready to upload the tune to our 2012 Jeep Wrangler JKU test mule. The 3.6L V6 was bone stock and a baseline dyno run scored a peak hp of 195.1 hp at 4,830 rpm and 226.0 lb-ft of torque at 4,090 rpm. The first step of the in-car installation was to turn the ignition key to the “on” (or “run”) position, but not start the engine. The GT Tuner blinked on and began at the Main Menu.

We then selected the vehicle model, engine, and year. Once that was done, the GT Tuner loaded the files, ask us to choose download, verify vehicle type, and retrieve data. During our installation, we found that the GT Tuner took a few minutes to upload and install these and many of the following files, so be patient, and do not interrupt the GT Tuner during these operations.

For 2012 and 2o13 Wranglers only, at this point in the process, you must go back to the computer with the MicroSD card in the card reader for another update. With this accomplished, we returned to the Jeep and began our final uploads. The GT read the engine files, one by one, and we dutifully kept following the instructions through quite a few cycles.

Eventually the GT prompted us to select through its catalog of tuning features that include Power Level, Drive Rev Limiter, Neutral Rev Limiter, Speed Limiter, MDS (not applicable to Jeep Wrangler), the Adjustment of the WOT Shift Points (for automatic transmissions only, our Wrangler was a five-speed manual trans model), Tire Size, and Axle Ratio.

One of the most useful features for day-to-day operation is the Driving Coach. It’s a graphic representation of your driving efficiency and can help improve long-range fuel mileage.

We toggled through to the desired selections where appropriate or desired, installing the various tuning features. Then we began to select the Jeep Special Functions. This is the one of the most interesting features of the Bully Dog GT Tuner For the Jeep. It allows you to set up and control certain functions such as Engine Fan, Idle Adjust, Tire Pressure, Sway Bar, Axle Lockers (Rubicon model only) directly from the GT Tuner.

The Engine Fan feature allows you to turn the engine cooling fan off for water crossing or run it at high speed at any temperature. Idle Adjust allows the user to set the engine speed (RPM) higher than normal idle to increase the alternator’s amperage output, providing additional power to the winch when needed.

Three power levels are available: Trail (softens accelerator tip-in for rock crawling), Regular (for 87 octane fuel), and Premium (for 91 octane fuel).

Tire Pressure eliminates the dash warning lamp so the tires can be aired down for increased traction off road. Sway Bar controls the electronic-disconnect sway bars on Rubicon models, and Axle Lockers helps to increase traction by engaging lockers up to 30 mph.

After we had gone through all of these selections and uploads, the GT Tuner built and then downloaded the tuning file into the Jeep. Again, this takes some time, and we just followed along with the instructions, not interrupting, while it was downloading.

Eventually, the GT Tuner signaled that the download was complete, and that is when we slid the switch on the adapter plug to “KEY.” After the installation was complete, we buttoned everything up and were ready to go test drive the new Bully Dog GT tuned Jeep, but not before we made a final dyno run.

The after-installation run (see the first chart below) on our Dynojet dynamometer revealed a boost of 202.5 peak hp and 229.0 lb-ft of peak torque in the Regular Tune. This is not a huge gain–we had the 50-State (California) tuner, see two dyno charts (hp on top, torque below) at bottom from Bully Dog showing performance gains from its 49-State tuner–but it did give the 3.6L V6 more power, and the Bully Dog GT Tuner allowed the power to stay on longer (through its engine RPM modification feature), as we could now run the engine out to 6,000 rpm.

More significant though, were the multitude of special ops offered by the Bully Dog GT Tuner, especially the off-road features such as those that allowed for increased amperage to the winch by temporarily increasing engine idle speed, control of the e-lockers and electronic-disconnect anti-sway bars, as well as fan control for deep water fording. These features provide greater control of the vehicle and make the vehicle a more capable off-roader.

Bully Dog claims performance gains as much as 40 lb-ft of torque with 91+ octane gas using the High Octane Tune, but as Yung at SCT Bully Dog said, “The most useful features are the monitoring and special functions. We wanted people to be better informed about what’s happening with the vehicle; and the tuner allows growth for the beginner, as enthusiasts always want to make improvements and modifications to their vehicle.”