We've seen all the advertisements and heard all the pitches. How these after-market programmers can add 25 horsepower instantly, increase fuel economy and make you better looking. So, we decided to pull together all of the programmers and power modules available for a nearly-new Jeep Wrangler and test the things that you're probably wondering about if you are thinking about buying one of these. Things like how much more power and can I really feel a difference? What's the effect on fuel economy? How hard are they to install? And what else can these do for me?
In addition to 0-60 mph performance...
In addition to 0-60 mph performance testing, we logged 7,000 miles over three months and kept track of every drop of fuel to test fuel economy of the programmers and performance modules. For consistency, the miles were measured during the same daily 106-mile commute, no cargo was carried, and the AC was not used. Driving style was maintained as much as possible.
It's probably not news to you that the vehicle tuning, and therefore performance, on your late-model Jeep is completely computer-controlled. How much fuel and how much spark, at what rpm and under what load are all decisions made by a tidy and tightly-controlled chart inside your Jeep's computer. If you have JK, WK, or XK, then even your gas pedal is just a rheostat switch that provides input into your vehicle computer - no more throttle cable! So if you want to make some more power or improve your fuel economy, your solution should probably start with the click of an electrical connector.
We started with an automatic '08 Jeep Wrangler Unlimited Rubicon that had about 7,600 miles on the clock. This means it was broken in, but not worn out. It was also completely stock. We then put 7,000 more miles on the Jeep over the next three months, logging fuel consumption, playing with features, doing acceleration runs, and generally living with the daily-driving characteristics of each programmer or module.
We even used the same gas...
We even used the same gas station for every fill up to try to keep everything as consistent as possible. All of the performance modules and programmers delivered a performance gain, and nearly all of them delivered better fuel economy. That's having your cake and eating it too! Some of them delivered a gain in gas mileage of about 7-percent in our testing.
All of our acceleration testing was done at the same time to control variables such as temperature, miscellaneous wear and tear on the vehicle, and so on. While we included advertised power-gain numbers in the At-a-Glance chart, no one drives a dyno, so we decided to do 0-60 mph testing. This is something you do every time you get on the freeway, and most people can relate to it. You also know that a 1/2-second improvement in 0-60 is something you can feel, while a 0.05-second improvement isn't, at least not in a six-cylinder Jeep Wrangler.
Fuel economy was logged over three months. The miles tracked were during a 106-mile daily commute. The drive was about 60 percent freeway, and the remaining miles were on surface streets. Accessory use and cargo in the Jeep were kept consistent to minimize variables in fuel consumption.
The JET Stage 1 module and...
The JET Stage 1 module and Unichip Plug-n-Play Kit install underhood. This requires disconnecting the battery and removing either one (for the JET unit) or two (for the Unichip kit) of the factory wiring harness connections from the Powertrain Control Module (PCM). The PCM on a JK is located on the driver-side inner fenderwell, just behind the radiator and windshield washer reservoir.
We have to admit that we were skeptical when we started the testing for this article. After all, just the premises of better performance and better fuel economy seem at odds with each other. But we were surprised that they all delivered what they promised. Exactly how much they provided varied, as did the features each one offers. Check out our At-a-Glance chart for side by side comparisons.
Meet the Players
There are two flavors of electronic tuning devices for the Jeep JK. One category is programmers. These connect to the vehicle diagnostic port and download a new calibration or tune into your factory computer. The advantage of these units is that you can program a variety of other items, such as correcting the speedometer after you change tires and gears. Some allow you to do even more, which we'll talk about later. The other category of tuning devices is an in-line computer, sometimes called a piggy-back computer. These units leave the calibration in the factory computer and adjust the engine tuning inline. The advantage of this type of system is that they leave no trace of ever being installed. While neither programmers nor in-line computers void the factory warranty, the in-line systems leaving no footprint saves you from ever having that conversation with your dealer. Both of these types of systems are easy to install and require no real mechanical knowledge.
The AEV, Hypertech, Pro Comp,...
The AEV, Hypertech, Pro Comp, and Superchip programmers plug into the diagnostic port, located under the driver's side of the dashboard. These units are connected to the vehicle only during programming, not during normal driving. They all fit in the glove box so you can carry them with you in case you want to change anything on the trail, or anywhere else for that matter.
We literally tested every programmer and power module available for the Jeep JK (or at least everyone that we're aware of): AEV, Hypertech, Pro Comp, Superchips and Unichip. Almost every one of these has some unique offering - something that makes it standout from the others.
During the more than three months we spent testing these products, we found that every one of them offered performance and fuel economy gains. We didn't experience any hiccups in vehicle calibration and we had a lot of fun playing with the various features some of the programmers included. In the end, all of them offered a performance improvement that we could feel with the seat of our pants, so the right one for you will depend on exactly what features you're looking for.
AEV ProCal Module
The team at AEV didn't feel the need to mess with performance and fuel-economy calibrations, but decided to focus exclusively on control and features that are important for real off-roaders. Beyond the basics of resetting diagnostic trouble codes and recalibrating the speedometer when you add larger tires and change the axle gear ratio, there are several off-road friendly features. It can adjust the tire-pressure monitoring system so the alarm activates at a lower pressure, or turn the alert off altogether. You can also raise the idle rpm for winching, using an air compressor, or welding. One of the coolest features found only in the AEV unit is the steering-wheel centering mode.
The AEV ProCal offers control...
The AEV ProCal offers control over the systems that matter most to off-roaders. Like turning the tire-pressure monitoring system down or off. And, it is relatively easy to use. By moving DIP switches, there are about ten different features you can use. The ProCal is also what AEV uses to set up a new PCM when doing one of its HEMI swaps.
Most Electronic Stability Program (ESP) trouble after a JK is lifted is caused by the steering wheel not being centered properly, and as a result, the steering-wheel angle sensor is off. Additional features include being able to activate daytime running lights and turn off the one-touch turn signals. A key benefit of the AEV ProCal is that it costs roughly a third of most of the other modules in this article. It doesn't give you more power or fuel economy, but it's a bargain if you're only interested in the features it does offer. AEV also includes the ProCal with its Nth Degree premium suspension kits.