Mark Houlahan
Tech Editor, Mustang Monthly
June 1, 2004

Horse Sense: The vendors contacted for this guide all have technical assistance via phone or Web access, along with extensive dealer support throughout the country. If you don't understand how Ford's EEC IV or EEC V works, or how to tune or replace it with the product you bought, seek help directly from the company or contact one of its dealers to schedule time to tune your project. The last thing you want to do is hurt that expensive engine you just finished building by accidentally adding 50 degrees of timing.

Whether you have an '03 Cobra with a pulley and a cold-air kit, or a banging '86 GT with a screaming, stroked EFI 351 Windsor under the hood, chances are your car needs some tuning. In this day and age of micro this and flash-memory that, it's often easier to tune hexadecimal code than it is to jet a Holley carburetor, with the right equipment, that is.

Speaking of equipment, there's a slew of products that will help you tune your Mustang. From basic plug-in chips (that come preprogrammed or can be custom tuned) to complete stand-alone, tunable fuel-injection systems that take the place of the stock electronics, there's an option for you. All the products discussed here offer control over fuel and timing curves. Where they differ is in how they offer this control and in what other features are available. So, what does your Mustang need? First you need to break down the categories of the available systems.

For basic tuning needs, there are off-the-shelf applications from companies such as Hypertech and Superchips. These chips are designed for certain upgrades or engine packages, helping them to perform at their best by adjusting the fuel and spark maps, as well as other PCM functions. The chips are usually preprogrammed, making it easy for the weekend wrench to install, and they provide a nice performance boost and better driveability. The chips are installed into the Electronic Engine Control's service port, also known as the J3 port at the rear of the EEC processor.

Next are custom chip-tuning products. These install similarly to a standard chip (read: driveway easy) but feature a custom-burned tune for your application. Typically, after completing a questionnaire, the chip is made to those specifications and shipped to you for installation. Such chips are capable of being reprogrammed if you make performance changes, and they often can be programmed with more than one tune for options such as nitrous, race fuel, and so on.

Best of all, if you work through the chip company's tuning network, you can have the chip programmed and dyno tested in your vehicle on the tuner's dyno for the best effect. These chips are installed in the same manner, through the EEC's service port. Probably the only negative thing about performance chips is-unless you have the chip burner and software to make changes yourself-you have to send the chip back for reprogramming or take your Mustang to one of the chip maker's authorized tuners.

Taking the performance ability of a custom chip and adding the ability to make instant tuning changes is the work of a different breed of product, now available from several companies. This product, a handheld programming device, works through the OBD-II port on EEC V vehicles. Simply plug in the device and you have the option of tuning your Mustang in several ways. Some products allow more freedom than others, but all offer handheld tuning without the expense of a chip burner and its software.

If you have a laptop computer, some companies can put custom chip tuning in your hands. The tuning devices connect to the PCM directly in a "piggyback" manner, and have a data cable that is connected to a computer or handheld LCD screen for tuning. The benefit here is that with a laptop you can see more of what's going on while tuning large maps across the entire rpm range. On the other side of the coin are the LCD displays that offer in-car tuning without the laptop. If you don't own a laptop, many of these products allow removal and programming at a desktop computer as well.