Dan Nicholas of Jet Performance
While people may have biases over which method of administering fuel they think is best, engines don't give a rip. Feed them well, and they will treat you well. This is evidenced by the fact that great carb tuners often make great EFI tuners. Although Jet Performance is best known for boosting horsepower through electronic wizardry, it cut its tuning teeth in the '60s modifying carburetors for NHRA Stock and Super Stock drag cars, showroom stock road racers, and circle track machines. The company's talents didn't go unnoticed, and Jet served as an OE consultant during the '70s, lending its expertise to designing cleaner, more efficient fuel systems. Naturally, with the proliferation of EFI performance cars in the '80s, Jet tapped into its vast pool of technical aptitude to unlock the potential hidden inside computer-controlled vehicles.
Today, Jet offers a full line of chips, hand-held programmers, and custom tuning software to electronically maximize the performance of just about any modern fuel-injected Bow Tie ever built. Jet has also expanded its reach by developing transmission components and various engine accessories in addition to a bevy of custom-calibrated race and street carburetors. To get the lowdown on the latest developments at Jet and pick up a few tuning tips along the way, we consulted Dan Nicholas. Here's the skinny.
"Chips were used on earlier fuel-injected GM vehicles where you would actually remove the stock chip (aka EPROM) from the computer and replace it with an aftermarket unit," says Dan. "Hand-held programmers are for newer vehicles that don't have removable chips, and they allow modifying far more programming parameters than the set program that was written on chips. It's just like the older computers that had 20 megabyte hard drives while today's computers often have hard drives larger than 500 gigs. Whether via a chip or a hand-held programmer, the major tuning changes made on gasoline vehicles are in the fuel and ignition advance maps. With our tuning, we typically see an 8-10 percent gain in horsepower and torque at the wheels. Additionally, newer vehicles allow modifying cooling fan thresholds, shift points, speedometer calibration, rev-limiters, and shift firmness."
Modern diesel motors are different animals than their gasoline counterparts, and therefore require a different approach to tuning. Since they implement bulletproof short-blocks pressurized by turbochargers, and burn their air/fuel mixture through auto-ignition, diesels pick up tremendous amounts of power through tuning compared to gasoline engines. For instance, a Jet Performance programmer can add up to 130 hp and 205 lb-ft on a GM Duramax diesel. There are some tradeoffs, however. "Getting the tuning right on a diesel is definitely a balancing act," explains Dan. "You want to get the perfect tune of air and fuel, because too much fuel without a sufficient amount of airflow to go along with it will dramatically increase exhaust gas temperatures and decrease the life of the motor."
"As density, altitude, and air temperature change, so must your tuning," Dan advises. "If you designed the fuel map for a 32-degree day, but it's 104 degrees at the track, then the thinner air will make the air/fuel mixture rich and reduce power. One of the best tools for tuning at the track is a wideband O2 sensor for accurate air/fuel ratio readings. This allows you to pick your proper jet sizes, or to dial in the correct fuel map in the case of EFI motors, and to set the proper ignition advance. Since running too lean can destroy a motor, it's not a bad idea to start by tuning it in the other direction first by running rich before leaning it out, just to be safe."