With a curb weight of 4,672 pounds, the wonderfully versatile but nonetheless large Gladiator Rubicon tips the scales at least 200 pounds heavier than even the portliest four-door Wrangler Rubicon powered by the same 285-horsepower Pentastar V-6—and it's more than a 500-pound weight penalty over a two-door Pentastar-powered Wrangler Sport.
That's a lot of extra poundage to pull around, especially on steep grades. In fact, the Gladiator's 16.4:1 power-to-weight ratio—each of the engine's 285 horses is responsible for lugging 16.4 pounds of the vehicle's mass over the hill or boulders—is a 5 percent disadvantage over the four-door Wrangler Rubicon's 15.7:1 ratio; and it's a significant 17-percent increase in work for each hard-working horse under the hood, compared to the two-door Wrangler Sport's 13.7:1 ratio.
More power as a solution is a universal truth—and a new supercharger kit for the Gladiator (and other 2018-20 Jeep
JL/JT models) from Hamburger's Superchargers accomplishes just that by cramming more air (8 psi) into the 3.6L V-6 to boost its output to 425 horsepower and 365 lb-ft of torque. It's a strong, nearly 50 percent horsepower jump that reduces the power-to-weight ratio to 11.0:1. It's a real-world power increase that's felt across the rpm band, but particularly at mid-range and higher engine speeds, as the centrifugal design of the blower pushes more air as rpm climbs.
| 02 Jeep Jt Gladiator Supercharger Installation
It's a design feature that offers more controllable power delivery, compared to the right now power of positive-displacement superchargers, which make the vehicle easier to control on trails or when maneuvering over rocks. The extra power, particularly the 105-lb-f. boost in torque, also helps offset the added weight that comes with typical aftermarket suspension, chassis and wheel/tire upgrades.
We should probably also mention at this point that while this supercharger system delivers a significant power increase, it won't turn a Gladiator into a Grand Cherokee Trackhawk competitor. Then again, that was never the goal with its development.
"It's designed to offer greater all-around performance," company founder Ed Hamburger says, "but without turning the Gladiator into a dedicated high-performance vehicle. It's power you can use without sacrificing everyday drivability or utility."
That's exactly what we found in a before/after review, which included documenting the installation and dyno-chassis testing. The power increased steadily and linearly as the rpm climbed, but its application was transparent and smooth. In fact, we were pleasantly surprised by how unobtrusive the kit was.
| Before digging in to the installation, our Gladiator project vehicle was strapped to a chassis dyno, where the stock output was calculated. Its SAE-corrected results were pretty much spot-on for the factory's 285 horsepower and 260 lb-ft of torque. A little more of each would help offset the truck's comparatively portly 4,672-pound curb weight.
In a word, it was quiet. Very quiet. In fact, no one riding in the cabin would suspect there's anything by the stock engine under the hood, even at wide-open throttle. And from the outside, you don't hear the supercharger. The whirring of a couple of electric fans for the kit's oil cooler is distinctly audible, but no more so than a production electric fan that kicks on. The quietness is due mostly to the fact the compressor doesn't have a conventional gear drive to make that characteristic supercharger whine.
As for the kit's details and the installation, there are a few important items to note:
- The supercharger system is intercooled, and the compressor has its own, dedicated oil supply. That means there's no need to drill into and tap the original oil pan for an oil feed. Very nice.
- The kit includes higher-rate fuel injectors, colder-range spark plugs and a two-bar MAP sensor, but no additional fuel system changes or enhancements are necessary.
- No exotic tools are required for the installation, but some trimming of factory components is required. Someone with moderate mechanical experience could handle the installation personally, but access to a lift definitely makes the job go easier.
- The factory engine control module (ECM) must be shipped to Hamburger's Superchargers to be unlocked and re-flashed with a new calibration for the system, which adds a little downtime to the project, but we're told it only takes a couple of days to turn around the controller.
- We're told that once testing and certification is completed, the kit will include a CARB E.O. number that will make it 50-state-legal, as long as no other engine modifications are made (cat-back exhaust systems are fine).
| The basics of the $6,495 kit include the supercharger itself, along with an air-to-air intercooler, higher-rate fuel injectors, and oil cooler for the supercharger's self-contained lubrication system, custom brackets and hoses, a new serpentine belt, and more.
The other big consideration is cost, and the bolt-on kit, as shown here in our story, carries a retail price of $6,495. Value is always in the eye of the beholder, but that's a pretty strong bang-for-the-buck ratio these days; and the system's comparatively quick and easy installation means the installation should be handled within a day, whether at a home garage or outsourced to a professional shop.
We should note, too, that the accompanying photos provide an overview of the kit's installation, not a look at every nut and bolt involved—that's what the instruction manual is for. These shots illustrate what's involved and the approximate wrench-turning experience required.
We're also told Hamburger's Superchargers is very close to securing a deal that would make the purchase and installation available through Jeep dealerships, but regardless of who installs the "blower," the results strengthen the already tenacious Gladiator.
More power is always the solution.
| The supercharger is a centrifugal design that incorporates a unique fluid traction drive system to spin the impeller rather than the gear-driven designs of other centrifugal compressors. It enables greater impeller speeds, to help make more boost, but without the conventional gear drive, the supercharger is incredibly quiet. In this application, the blower is good for about 8 pounds of boost.
| We're getting a little ahead of ourselves with this photo, but the important thing to note here is the location of the engine control module (arrow), which must be removed and sent to Hamburger's Superchargers to be re-flashed for the supercharger system. There are two connectors to remove from the module, along with three bolts holding it to its bracket. It's a good idea to send in the module prior to the kit's installation, so that it's ready to go when the blower is finally in place.
| The grille, the lower grille shroud, skidplate, and a number of other front-end components must be removed to allow installation of the intercooler's heat exchanger, the supercharger's oil cooler, and routing of the various hoses for the kit. Fortunately, it's all simple stuff to remove, with easily accessible pins and fasteners, but one of those plastic pin/trim removal tools makes it a lot easier.
| The factory air intake tract comes out next, and care must be taken to remove and retain the original intake air temperature (IAT) sensor, which must be relocated within the kit's intake tubing.
| Next to be removed is the stock air box. It will get modified to accommodate the routing of the new air intake tubing.
| After that comes the upper intake manifold, which also requires the removal of the EGR valve and other hoses and connectors before it lifts off the engine. Also, the purge valve for the fuel system must be disconnected before the manifold is removed. Caution must be taken when doing so, because the fuel system is under pressure.
| The manifold has to be removed to gain access to the fuel rail, which is held on with four T30 (Torx) fasteners. The wiring harnesses for each injector must also be disconnected, along with the fuel supply to the rail. The two halves of the rail—left-hand and right-hand—should be removed as a unit and not separated.
| The kit's new, higher-rate injectors simply replace the original injectors in the fuel rail. They include specific O-rings that must be used in order to fit properly in the lower intake manifold.
| Access to the coil packs is easier with the upper intake manifold removed, making it a good time to swap the original spark plugs for the colder-range plugs included with the kit. The faster heat transfer rate of the colder plugs is necessary to accommodate the higher cylinder pressures and resulting temperature increases that come with supercharging.
| With the upper intake manifold reinstalled, a new, two-bar MAP sensor replaces the original sensor. A little grinding on the factory mounting tabs is required to properly seat the new sensor.
| The alternator must be relocated to the bottom of the engine to make room for the supercharger, so off it comes. There are four bolts holding it in place. The mounting bracket comes off, too.
| Routing of the new serpentine belt may come a bit close to a protruding part of the aluminum block, behind the alternator bracket's location. Although it shouldn't pose a problem, grinding away a little material provides a little more room and the peace of mind of adequate clearance.
| The alternator mounts from below (with the skidplate removed) with a new bracket supplied with the kit. It's a tight fit and installed easier with the assistance of a lift, but it's certainly doable by lying beneath the vehicle and lifting it into place, too.
| After relocating the alternator, the power supply wire and a couple of other control wires or it must be extended. The kit includes the necessary wiring and hardware to do the job.
| The supercharger assembly goes on next, after the compressor is mounted to its bracket. A factory idler pulley is transferred to the bracket, and there are a couple of spacers to be installed, too, all to align the supercharger pulley with the rest of the accessory drive system.
| Before the pressurized air from the supercharger enters the engine, it flows through this air-to-air intercooling system, with a heat exchanger mounted in front of the radiator. It lowers the temperature of the pressurized air charge, sending a denser charge into the engine, which promotes greater power.
| It's necessary to trim corners in the plastic framework supporting the headlamp assemblies in order to make room for the intercooler system's inlet and outlet tubing.
| A vacuum-actuated recirculation valve, also known as a bypass valve, is supplied with the kit and installs within the intake tubing. It works as a pressure relief when the throttle closes, sending the air back into the system intake system.
| The tubing culminates at the throttle body. Note the port in the kit's tubing to accommodate the factory IAT sensor.
| Next up is the oil cooler for the supercharger. It has a dedicated heat exchanger and a couple of cooling fans that attach to it (with complementing wiring that simply plugs into the factory fuse box). The assembly mounts between the bumper and radiator core support. And yes, it can be mounted elsewhere, if an aftermarket bumper makes this position inaccessible. It just can't be mounted higher than the oil reservoir itself.
| And speaking of the reservoir, it mounts between the brake booster and driver-side inner fender panel. To be honest, this was the most awkward part of the project, because there is little room for it and even less room to maneuver one's hands to bolt it in place. After that, a feed line is routed between it and the supercharger, as well as the cooler.
| Nearing the close of the installation, the factory air box must be cut out at the bottom corner, as shown here, to make room for the intake tubing. The cut-out corner isn't visible when the air box is re-installed.
| Here's a look at the kit's installation, showing a wider view of the tubing routed through the engine compartment. It's a tight fit, but it all fits neatly under the hood and behind the front fascia. It's important at this stage to double-check that all the hoses and electrical connections have been reattached.
| Finally, the skidplate and front fascia are reinstalled, along with the re-flashed engine control module. It took less than a day to do the installation, and the engine fired immediately after the controller was reconnected. It was a straightforward project that didn't trigger more than a couple of four-letter words—and no thrown tools!
| Back on the chassis dyno, the SAE-corrected results showed 427.5 horsepower and 364.7 lb-ft of torque at the flywheel—142.5 horses and 104.7 lb-ft more than stock—from 8 pounds of intercooled boost. That's a great result, no matter how you measure it.