Mark Houlahan
Tech Editor, Mustang Monthly
April 1, 2003
The DiabloSport DeltaChip comes with a three-position toggle switch (on the end of one harness), a tube-key antitheft switch, an antitheft wiring harness, and the DeltaChip assembly.

Horse Sense:
The DeltaChip has an optional antitheft key switch that disables the chip, thus preventing the vehicle from starting. The key switch isn't Fort Knox, but if it's cleverly hidden (and routinely used), it is yet another obstacle a would-be thief has to overcome to take your ride.

The typical computer-chip upgrade is a replacement or add-on chip that replaces the stock computer's look-up tables for timing, fuel, rpm, fan speed, and so on (depending upon application) with custom-tuned tables. Most all chip designs allow for custom tuning as well. You can purchase an off-the-shelf chip upgrade that has many of the stock parameters tweaked for performance, or you can go to a chip tuner who will take a blank chip and customize it to your particular vehicle's attributes-perfect for one-off combinations, stroker engines, and race setups.

Computer-chip upgrades have been around since the late '80s. The first chip design was used in GM computers where the physical chip could be removed from the circuit board and replaced with another chip. The Ford computers proved to be a different beast altogether since the circuit boards had soldered chips. However, it was soon determined that the Ford computer could indeed be "chipped" by using the service port found on the back of the computer case. The Ford-style chip required its own circuit board with attaching hardware. In later years, several designs came out using various mounting techniques for the Ford computer. Today there are still several manufacturers of performance computer chips for both EEC IV and EEC V fuel-injected Mustangs (and other Ford products as well).

Since the aftermarket performance chip is installed on the computer-or EEC IV-access to the EEC is required. We spent the day at Steeda Autosports, a DiabloSport dealer, where we were graciously allowed to use the Dynojet and the company's personnel. Here, Johan Mangs of DiabloSport removes the PCM from Scott Boda's 408 Windsor-powered LX.

For this article, we opted to use DiabloSport's new DeltaChip. The Delta-Chip is not one, but three computer programs on one chip. The first program is always a stock tune-the way the car was without a chip-while the second and third tunes can be programmed for just about anything. We'll be using the two alternative tunes for performance tuning with and without nitrous. The options are up to the vehicle owner and chip tuner, but you could use the two separate tunes for such things as street and race fuel, street and race rev limit, and much more.

Follow along as we show you how to install the DeltaChip.

Custom Tunes R-Us
While you can contact any DiabloSport dealer and have your DeltaChip programmed for your vehicle's particular setup, we thought it would be interesting to show you how a DiabloSport dealer would accomplish this. Since Steeda is a DiabloSport dealer, we simply followed along as Johan Mangs from DiabloSport went through the acts of programming our DeltaChip from the DiabloSport dealer Web site while we were at Steeda for this article.

For dyno testing, longtime Steeda technician Chad Coy spun the rollers during our visit, while Scott ran the nitrous testing since he was most familiar with his car's nitrous system. For the most accurate air/fuel ratio information, a wide-band O2 sensor was used during testing, which helped immensely with the minute changes that occur during chip tuning.

We didn't realize until halfway through testing that Scott had played with the 408's cam timing just a few weeks earlier. His cam had been advanced 2 degrees, and he had recently retarded it back to "straight up," losing 20 hp in the process. Patrick's chip tuning didn't help much during naturally aspirated runs. We speculated there was an inherent internal-engine concern since major changes in air/fuel ratio and spark timing didn't make any difference from one run to the next. Hopefully, Scott will figure out the problem and we can revisit this tuning operation for some dyno

The DiabloSport programmer/reader unit is part of the dealer kit that DiabloSport sells. This device is connected to a PC with an Internet connection and is capable of reading EEC calibrations and DiabloSport chips, as well as writing to Diablo-Sport chips. The Internet connection is used for uploading new calibrations or downloading existing ones. The existing calibrations, or "tunes," are purchased with "Web ticks"-sort of a DiabloSport currency, if you will.

The main screen of the dealer-access area on the DiabloSport Web site allows the dealer/tuner to select the proper type of chip and EEC being used so that the software points to the proper selection screen.

Once the dealer/tuner hits "enter," the selection screen based on the information input is shown. Here the dealer/ tuner can choose from various tunes provided by DiabloSport and other tuners. A quick glance at this screen and you will see popular combinations such as centrifugal blowers, E-cams, 347 strokers, and more, making the tuner's job much easier and less time consuming. Of course, if it's required, custom tuning from scratch is not a problem with the DiabloChip.

With the naturally aspirated numbers hovering near the baseline, the only thing left to do was tune the second program on the DeltaChip for Scott's nitrous system. After Patrick reconfigured the rev limiter, the timing retard, and a few other functions, the DeltaChip was programmed. The chip's main toggle switch, which switches between the three programs, is installed under Scott's stereo where existing fuel pump and nitrous switches are located.

The completed switch installation looks clean, and the LED beside the switch identifies which tune program Scott is using. The DeltaChip is set up to allow on-the-fly switching from "tune 2" to "tune 3" but not into or out of "tune 1." To engage "tune 1", the ignition must be cycled off and back on.

The location of the antitheft key switch is up to the owner-of course, it must be within the reach of the wiring harness. Since Scott's '90 LX didn't have a fuel-door release button, the decision was made to mount the switch in the glovebox where the fuel-door button would be. This keeps the switch hidden from view, and has the added benefit of allowing the glovebox door to be locked, creating more problems for a would-be thief.

The final installation of the antitheft switch is shown here. The key does not need to stay in the switch for operation; we simply left it in for the photo. Make sure to keep your key with your car keys and not in the console or glovebox, where it could easily be used to defeat the antitheft switch's purpose.

One last dyno pull by Johan and Patrick ensures the switch and antitheft device are working properly. 5.0


The final step to the antitheft and DeltaChip switch wiring is to plug the preterminated wire harnesses into the DeltaChip and then reinsert the chip into the EEC. Route the wiring and tape or tie-wrap it securely to prevent any abrasion damage to the harnesses.