Jerrod Jones
Former Editor, Off Road
Photographers:
Banks Power
Too many 4.0L Wrangler owners have a Fifth gear (or overdrive gear) that is collecting dust, not having been used since the Jeep had stock tires. Adding bigger tires, axles, and body armor can all weigh your rig down. It sucks to be stuck with lackluster power after you’ve spent thousands of dollars on everything else. Why wouldn’t you spend another few grand on some serious power improvement?
In the case of a V-8 swap, however, there are a couple reasons why this is not a good plan. First, a “good” fuel-injected V-8 swap costs a few thousand dollars. Adapters and/or transmissions and T-cases will be needed. New drivelines need to be made. Crossmembers and oil pans have to be modified. The list goes on. Depending on where you live, there can be tricky hoops to jump through to legalize your engine swap. Doing a swap in a county that tests for emissions means that you’ll be getting to know your local smog referee intimately to certify your swap as legal. While they have a written set of general guidelines, every referee is human, which means he’s not perfect and certain things are open to personal interpretation.
There are stroker kits you could try and squeeze by the emissions test with. But name how many guys you know with 4.7L or 4.9L stroker kits that make more power and that don’t have any problems.
The Jeep 4.0L turbocharging system comes complete with the Sidewinder turbo, a Big Head wastegate, a Banks throttle plate, an Exclusive Ram-Air intake, and the 2 1/2-inch aluminized tubing that’s necessary to plumb the turbo into the intake and exhaust systems. A new serpentine belt is also included, as is a flash programmer to make your stock Jeep ECU perfectly control your turbocharged 4.0L engine. The intercooler kit is easy to install and comes with all required fasteners, brackets, preformed hoses, and sealed power harness connectors. The system is made to outlive your Jeep. Considering how long the 4.0L engines last, that’s really saying something.
If you’ve bought the bolt-on air intake, the throttle body spacer, the ignition kit, and a mild cam and you’re still not satisfied, the next (legal) thing you can do is the best thing: Turbocharge it. Starting at a few thousand dollars, the Banks Sidewinder 4.0L turbocharging kit can legally produce V-8 power in an otherwise stock inline-six Jeep 4.0L engine. The Sidewinder package comes with everything you need to add an additional 66 rwhp with forced induction to your TJ or LJ. With the optional liquid-to-air intercooler kit, a 102-rwhp gain can be achieved thanks to more oxygen-rich air due to a cooler air charge. Using the included flash programmer to reprogram your ECU, you can install a 50-state street-legal Sidewinder turbo kit in your driveway in a full weekend.
Sidewnder kits are currently available for 1999-2006 Jeep 4.0Ls. And this is only in Wranglers (sorry, XJ Cherokee guys). But rumor has it that there will be a race-only universal 4.0L turbo kit under Banks’ Outlaw brand soon enough.
After driving a Sidewinder turbocharged Wrangler over the Colorado Rockies all the way to Illinois (and back) for Ultimate Adventure 2014, we can attest that this turbo kit has more than proven itself reliable, durable, and powerful. The 4.0L Sidewinder’s turbo response is immediate, and there is no lag time making a ton of power continuously without spiking coolant or oil temperatures. Our test 4.0L is loving its forced induction complement and has every indication of running smoothly for another 100,000 miles.
The Sidewinder turbocharger has an integrated wastegate and compressor bypass valve. It’s a smaller turbine housing, sized for maximum and immediate response on a 4.0L engine. The compressor bypass valve recalculates boosted air back to the inlet so the turbo breathes more easily and the wheel speed can stay up to eliminate surging when the throttle is closed. An optional bypass spacer would dump hot air externally, quicken response, and create an unmistakable sound.
Since the turbocharger sits directly below the alternator once installed on a 4.0L engine, the alternator actually has to be moved up just a bit. Banks provides a cast iron mounting bracket to secure the turbine housing to the engine instead of hanging it off the exhaust. It also gives a new mounting point for the alternator.
The weld-in oil drain bung is the only step of the installation that requires more than simple handtools. The oil drain line heads straight down from the turbo into the oil pan to keep the line short and up out of harm’s way. The plastic black tube heading into the turbo inlet is the turbo-specific Ram-Air intake with the through-the-hood Super Scoop.
Supplied 2 1/2-inch aluminized exhaust tubing interrupts the factory exhaust after the Y coming down from the exhaust manifold. It expels gases directly to the turbo, while new tubing is also supplied to meet up to the factory muffler and remaining exhaust system.
The turbine housing is wrapped with protective aluminized blanket that keeps heat energy inside the turbo and prevents heat-soaking the surrounding components under the hood.
The stock throttle body remains but an adapter plate (also compatible with aftermarket throttle bodies) is bolted between the intake manifold and the throttle body. It gives a port for a new two-bar MAP sensor and provides necessary vacuum/boost port connections.
While you may choose to install the Sidewinder 4.0L turbocharging kit yourself (which is totally possible thanks to the included flash programmer) you can also drop your Jeep off at Banks to have a turnkey installation done for you. You drive in, drop off your Wrangler, a complete installation and all tuning is done for you, and you drive home with a 60 percent power increase. By the time you read this, there will also be new JK Wrangler Sidewinder kits for 2007-2014 3.8L and 3.6L V-6 engines. Earlier generation (pre-1999) 4.0L Wrangler turbo kits are being currently investigated by Banks Engineering, and there is talk of XJ Cherokee turbo kits as well.
A Sidewinder 4.0L turbo kit will look this nice once installed. The powdercoated boost tube over the engine has an 1/8-inch NPT port for the addition of a water/methanol injection system, should the owner desire one. If an intercooler is added at the time of turbo installation (or later ), the intercooler and two shorter boost tubes will be installed.
Fifty-state legality makes a big difference. While a lot of guys live outside emissions-testing counties or use their vehicle for “off-road only,” a good majority of us have to worry about emissions legality and would prefer to keep our Jeeps running cleanly. Banks was sure to get the CARB EO (California Air Resource Board exemption order) numbers to verify that all the Sidewinder Jeep turbo kits are legal for sale and use anywhere in the United States.
Stock Power vs. Sidewinder Turbo With Intercooler
How Does It Perform?
We spent a lot of time using the Sidewinder turbocharging kit on the Ultimate Adventure in a turbocharged 2005 Wrangler Unlimited with 37-inch Trailer Grapplers and a ton of body armor. Even driving over the Colorado Rockies at high altitudes, packed with camping gear, the turbocharged Wrangler was holding gear in overdrive (automatic transmission) at over 70 mph while engine temperatures kept cool. Power in off-road situations came on immediately. The small turbo spooled up quickly with almost no lag time. We never saw the temperature spike to more than 218 degrees, and we think that was probably a small air pocket since the coolant temperature immediately came back down.
Add 102 hp With an Intercooler
The Sidewinder Turbo kit by itself adds a healthy 66 rwhp to your 4.0L engine by itself, and will run perfectly long all day long. But you can choose to cool the air charge for even more power. The intercooler increases responsiveness of the system even more, with a 50 lb-ft gain over stock as low as 1,600 rpm. Smooth drivability and linear throttle response are maintained for on- and off-road control, yielding steady power output even under extreme ambient temperatures. All that and the charge air temps are even cooler than stock, even with a small increase in boost over the base kit, allowing more efficient spark timing both on-power and while cruising.
