Feature > Manufacturer Profiles
Jet Performance
Helping Your Off-Road Adventures Take Off
by Steve Temple
photos by the manufacturer
Do off-roaders really need more horsepower? After all, if it takes just a bit longer to crest the grade, that just means more time to smell the sage, right? And what would we do with more torque, anyway? Wallowing in mud is such a kick, so why abandon that wonderful pig-like sensation? We also don’t need precise shifts from our automatic tranny. Maybe your machine prefers to peruse all its gears before deciding on the right one. We’re all perfectly satisfied with the same mediocre performance our suburban brethren endure when taking a treacherous weekend journey to the local hardware store, aren’t we?
To all of the above, we have one reply — Bogus.
We push ourselves and our trucks to the edge and then figure out how to go farther. We attack dirt trails; we tackle water crossings. The worst terrain on the trail was put here for our conquest. We don’t just drive our 4x4s, we live in them.
It’s that kind of passion that JET Performance Products has understood for nearly 40 years. This Huntington Beach, California, company has been on the same pursuit of peak performance since 1968. Back then Jones Performance Fuel Systems specialized in tuning anything that went fast-from drag racers and Winston Cup cars to off-road race trucks.
As carburetors fell by the wayside to fuel injection and computers were introduced to manage engine functions, Jones was the first company to develop computer-chip upgrades that met stringent smog restrictions in California.
In 1995, the company adopted the name JET Performance Products — from Jones Electronic Technologies. The reason was simple, according to vice president Dan Nicholas: there was nobody named Jones left at the company. Besides, the JET moniker better indicates a product line that appeals to the warriors among us and to the connoisseurs of pure performance.
While the JET catalog covers a range of tunable products and performance upgrades, it’s best known for automotive computer upgrades, from simple chip replacements to the most sophisticated programmers. With each step up the ladder in sophistication, more potential power is unleashed.
“The chip replacements were the first in the line,” notes Nicholas. “We were able to make minor changes in the vehicle’s performance.” Those minor changes resulted in as much as a 23-horse overall gain, along with more power across the full rpm range, not just at full throttle. These improvements were derived solely from adjustments to the air/fuel ratio and ignition advance, but the chips also were able to adjust transmission functions and other parameters.
Depending on the specific vehicle, the JET chips allow for two or three levels of tuning. Stage 1 is appropriate for stock vehicles using lower (89 or more) octane fuel. Fuel and timing curves are modified for optimal performance and improved gas mileage. Stage 1 is designed for towing or the daily drive with no additional modifications required.
The next rung up the performance ladder is Stage 2 tuning, an aggressive version with more horsepower and torque gains. Stage 2 requires 91-octane fuel, a 180-degree thermostat, and free-flow exhaust to accommodate the power gains. The Power-Shift mode combines Stage 2 tuning parameters and a program for electronic transmissions that provides more aggressive, precise shift patterns.
The last chip-equipped vehicle ever produced, according to Nicholas was the 1995 Chevy truck. By then, the OEs had in-line modules to govern the long menu of vehicle functions. JET’s answer was a replacement plug-in module that takes less than 30 minutes to install. The module includes the same tuning improvements and levels as the chips, but takes it further with improved throttle response and acceleration, plus improved low-end torque — which is where we need it.
Technology marches on, of course. The JET GM Performance Programmer allows the driver to retune his vehicle for specific driving conditions. Additional modifications, over and above the replacement chips and modules, include shift points and firmness as well as speed- and rev-limiter settings.
Original equipment programmers set speed and rev limits based on stock equipment, such as non-speed-rated tires and stock intake and exhaust. For street use, Z-rated tires can handle significantly more speed, but your vehicle is programmed to limit that speed — sheesh!
The same problem is encountered with other performance modifications that allow the engine to safely reach higher rpms and generate correspondingly higher power. The JET Programmer fixes all that, though, tapping the performance you’d expect from the upgrades. The best part of the Programmer upgrade is the power increase: up to 130 more horsepower and 205 pound-feet of torque, depending on the application.
For off-roaders with oversized wheel/tire packages or modified rearend gear ratios, the Programmer adjusts the speedometer/odometer and transmission shift points to accommodate the physical changes. In lay terms, your engine doesn’t recognize the above changes. It’s chugging along recording speed, miles, and shift patterns based on the stock tire size’s rotations. A single rotation of oversized tires covers more ground, and it does it faster. For instance, when the highway patrolman stops you for going 75, you can’t get out of the ticket by claiming your speedometer only registered 65, because of those new, beefy tires. You’re simply screwed-unless you have JET compensate for those off-road mods.
The icing on the computer-upgrade cake is JET’s Performance Six-Pack Chip for GM light trucks. In addition to the Stage 1 and 2 parameters, the Six-Pack offers four other modes. The Economy Mode, especially valuable with gas prices approaching the $3-a-gallon level, optimizes fuel delivery and ignition timing so the engine runs efficiently on 87-octane fuel. This mode is designed for long freeway stints or road trips when the wallet is higher priority than breaking the land-speed record.
Like the Economy Mode, the Towing Mode allows for the use of 87-octane fuel. In addition, it modifies the fuel and timing curves to increase low-end torque and midrange passing performance, plus it provides extra power for driving under load.
In the Valet Mode-okay maybe not something you’d consider for a 4x4 trip but still cool — restricts fuel delivery and engine rpm so the vehicle can’t do wheelies. This may be the button you’d want to push on your 4x4 if your hot-dogger friends are driving it.
Or if you have to leave your vehicle unattended in a remote location while you’re off skinny dipping or answering the call of nature, the Security Mode prevents the vehicle from being started by shutting down all fuel to the injectors. All you have to do is select the Security Mode and remove the key from the Six-Pack controller, locking in the setting.
For those whose 4x4’s model year hovers somewhere between carburetor and fully computer-controlled late-model truck, you can stlll take advantage of the latest in Module and Programmer technology that improves shift quality. JET’s transconversion kits may be esoteric for the off-road community, but they’re worth mentioning for four-wheelers who live to modify.
Here’s the deal: you’ve upgraded your truck with a GM 4L60-E tranny but the truck’s computer doesn’t manage the shift points. Or maybe your vehicle’s model year precedes computers all together. The kit includes a stand-alone control system that operates the tranny with software custom-tuned to optimize shift points, shift quality, and lockup converter functions.
While carburetors may be considered dinosaurs in this era of computer-controlled fuel injectors, they are still lurking in many 4x4s that have been reinvented and modified as weekend toys. Tuning race carbs was the springboard for JET and still plays a significant role in the company’s line of products and services.
“The Streetmaster Quadrajet is, hands-down, the best carb for off-roading,” says Nicholas. The Quadrajet’s float line is steady, so radical inclines won’t cause a rush of fuel, choking out the engine. JET completely disassembles, cleans, and upgrades customer Quadrajets to three stages of performance. Stage 1 restores the carburetor to factory performance. Stage 2 tuning improves idle quality and throttle response as well as torque and horsepower. Stage 3 is JET’s race tuning level with high-rpm fuel flow.
If all this sounds intriguing, but you don’t have a Quadrajet carb in your vehicle to send off to JET for retuning, the best bet is to contact the company and provide your vehicle information. The team of technicians can recommend the best carb for your vehicle and application — there may be some base plate modification.
JET also provides a series of accessories that provide specific performance upgrades. The Accu-Speed for 1993-and-later light trucks and the GM-specific Speed Control Unit 2000 correct speedometer readings and transmission shift points to accommodate non-stock gear ratios and larger wheel/tire packages.
JET’s Fan Switch and Low Temp Stat Thermostat turn on the cooling fan at a lower temperature, enhancing engine performance and longevity. Cooler running temperatures create a denser air/fuel mixture and increased horsepower.
Ideal for those massive tow vehicles with extensive menus of accessories, the JET Underdrive Pulley Set increases horsepower and gas mileage lost to the effort of the engine to drive those accessories. The pulleys slow down the accessories without negatively impacting their function. This slow-down allows the engine to function with less effort.
Okay, so maybe fewer of today’s off-road performance enthusiasts are spending their evenings fiddling with their carbs and fine-tuning the engine for their specific passion-whether that’s desert racing or rock crawling. Computer engine management is bringing an end to that era. But with the range of products available from JET, we still have the ability to crank out as much power as our engine can handle, whether it’s fed by a carb or controlled by a computer. And with all that tinkering time saved, we can spend more time where we belong — in the dirt.
Jet Performance Products at 4wheelparts.com.