Powerful Jeep Engines - 10 Proven Power Plays

    Dyno-Verified Engine Upgrades

    John CappaPhotographerChristian HazelPhotographer, WriterJohn SweetserPhotographer

    With all the power parts and combos we've installed and dyno'd over the years, it seemed a shame to just let them slip blindly into oblivion.

    So instead of forgetting where we came from, we dug through the Jp archives in search of some real-world, dyno-proven power-adders. whether just a single component like a turbo or nitrous system, or a carefully selected combination of aftermarket parts, here are 10 proven power plays you can make with your Jeep.

    July 2002, p. 86

    Power Play Combo:Intercooled 4.0l Supercharger

    For Jp's tJ project vehicle, red, Cappa, and crew kept the power upgrades simple.

    They brought the vehicle to avenger superchargers for the installation of the company's 4.0l intercooled supercharger system and a new set of 23lb/hr injectors to replace the factory 19lb/hr units.

    Vehicle Specs:
    2002 Jeep TJ Sport
    4.0L
    NV3550 transmission
    3.73 gears
    32-inch tires
    Power Gains:
    stock: 193 hp, 239 lb-ft*
    Modified: 266 hp, 348 lb-ft*
    *Note - numbers corrected to indicate power at flywheel, not rear tires

    Sources:
    Avenger Superchargers
    719/594-4766
    avengersuperchargers.com

    August 2006, P. 72

    Simple 4.0L Breathing
    Power Play Combo: Edge Trail Jammer Compete 4.0L System

    When it came time to upgrade the power level on Jp's project steal-J wrangler, we had no desire to crack into the stock, undamaged exhaust system.

    Rather, we concentrated our efforts on the intake and fuel side of the equation. Edge product's trail Jammer system utilizes a highflow, cold-air intake, a bored 62mm throttle body, and an electronic control module that increases the fuel delivery to complement the engine's ability to draw more air. the results in drivability and mileage were welcome additions, with gains of 15 hp and an increase in mileage of 1.3 mpg.

    Vehicle Specs:
    1997 TJ wrangler sport
    4.0L
    TF999 auto transmission
    3.07 gears
    30-inch tires
    Power Gains:
    stock: 126 hp, 171 lb-ft*
    Modified: 141 hp, 181 lb-ft*
    *Note - numbers taken at rear tires

    Sources:
    Edge Products
    888/360-3343
    edgeproducts.com

    December 2004, P. 32

    YJ Wheezer Squeezing

    Back in 2004, tech editor hazel suddenly found himself the owner of a cheap, 100K-mile '95 yJ with a good-running 2.5l and an aX-5 tranny.

    It was quiet, economical, and comfortable to drive, so naturally he modded the hell out of it until it was loud and uncomfortable. here's the power play and dyno numbers from the engine modification installment of the buildup. while it's impressive that we actually raised horsepower by 14 percent, the power came on at a much higher rpm and driveability actually suffered. in reality, it was a nicer-driving vehicle with the stock drivetrain. live and learn.

    Power Play Combo:
    Flex-a-lite electric fan, pn 475
    Banks torquetube header
    Banks stinger exhaust random technolgies high flow catalytic converter,pn 822201
    Stock 58mm 4.0l throttle body
    AEM Brute Force air intake and filter

    Vehicle Specs:
    1995 YJ wrangler
    2.5L
    AX-5 transmission
    4.10 gears
    29-inch tires
    Power Gains:
    stock: 100 hp, 121 lb-ft*
    Modified: 114 hp, 128 lb-ft*
    *Note - numbers taken at rear tires

    Sources:
    AEM
    310/484-2322
    aempower.com

    Banks
    800/601-8069
    bankspower.com

    The Dyno Shop
    619/562-3933
    thedynoshop.com

    Flex-A-Lite
    800/851-1510
    flex-a-lite.com

    Random Technology
    770/554-4242
    randomtechnology.com

    December 2004, P. 46

    XJ 4.0L hop up

    Power Play Combo:
    Performance Distributors 4.0l Firepower
    Ignition Kit, Pn 4.0Kit
    Performance Distributors
    Harness Adapter, Pn
    1728-Ah
    K&N Fuel Injection
    Performance Kit, Pn
    57-1518
    Gibson Stainless Steel
    Header, Pn Gp400s
    Gibson After-Cat Exhaust, Pn 617200
    Rubicon Express 62mm
    Throttle Body, Pn Re1062Hypertec PowerProgrammer III

    Vehicle Specs:
    1999 XJ sport
    4.0L
    aw4 auto transmission
    4.88 gears
    33-inch tires
    Power Gains:stock: 133 hp, 176 lb-ft*
    Modified: 152 hp, 200 lb-ft*
    *Note - numbers taken at rear tires

    One of our more highly modified project vehicles is Jp's '99 XJ sport dubbed, project Jr. Back in the days before we swapped the stock 4.0l out for a 4.6l stroker, hazel came up with a pretty stout combination of aftermarket components that eked an extra 19 hp and 24 lb-ft from the stock 130,000 mile engine, improving driveability at all engine speeds. here's our recommendation for one of our all-time favorite power-adder combos for a 4.0l Jeep vehicle.

    Sources:
    The Dyno Shop
    619/562-3933
    thedynoshop.com

    Gibson
    800/528-3044
    gibsonperformance.com

    Hypertech
    901/382-8888
    hypertech.com

    K&N Engineering
    800/858-3333
    knfilters.com

    Performance Distributors
    901/396-5782
    performancedistributors.com

    Rubicon Express
    66/523-7710
    rubiconexpress.com

    August 2005, p. 20
    Free squeeze for the ubiquitous inline
    Power Play Combo:
    505 performance 4.0l turbo kit
    MSD Boost timing Master ignition control

    Since there's no beltdriven compressor involved, turbo charging is pretty much the closest you can come to adding free horsepower to your vehicle.

    Sure, there are tradeoffs (most of which can be cured with an intercooler), but for the sake of simplicity, 505 performance has developed a turbo kit for the 4.0l that gets you gobs of power with few drawbacks. the 505 performance kit is pretty complete, including the turbo, mounts, and even a new oil pan already plumbed for the oil return line. the increase in fuel needed to keep the air/ fuel ratio happy at the designed 6psi boost is handled by 505's vacuum-referenced Fmu (fuel management unit). the FMu mounts inline on the fuel rail and adjusts fuel pressure according to engine vacuum and boost levels. our tester discovered on his manual transmission-equipped tJ some knocking at certain engine loads, so an Msd boost timing master was installed to automatically draw back the timing as boost increased to help prevent detonation.

    Sources:
    505 Performance
    505/325-3533
    505performance.com

    MSD
    915/857-5200
    msdignition.com

    Redline Motorsports
    970/221-4805
    4redlinemotorsports.com

    Vehicle Specs:
    1999 TJ sport
    4.0L
    aX-15 transmission
    3.73 gears
    31-inch tires
    Power Gains:
    stock: 148 hp, 191 lb-ft*
    Modified: 214 hp, 281 lb-ft*
    *Note - numbers taken at rear tires

    December 2005, P. 72
    Upping Displacement From 4.0L To 4.6L
    Power Play Combo:
    Golen Engine Service 4.6l Long
    Block
    Accel 23lb/Hr Injectors
    Turbo City Ignition And Injection Tuning After being bitten by the more-horsepower-is-better bug, hazel commissioned Golen engine service to build one of its 4.6l stroker engines to replace the 4.0l in Jp's '99 XJ project vehicle, Jr.

    The Golen long block utilizes a 4.2l crank to eke out an extra 0.6l of displacement. the engine also has more compression, a more-aggressive cam, and better valves in the head. after finishing the long block swap, hazel took the Jeep to turbo City in anaheim, California, to be tuned and to ensure a proper air/fuel ratio with the larger engine. part of that was replacing the factory 19lb/hr injectors with larger 24lb/hr units. the numbers below demonstrate the difference in power from 4.0l to 4.6l with only the long-block, injector, and turbo City's tuning modifications.

    Sources:
    Accel
    888/Mr-GasKet X999
    mrgasket.com

    The Dyno Shop
    619/562-3933
    thedynoshop.com

    Gibson
    800/528-3044
    gibsonperformance.com

    Golen Engine Service Hypertech
    901/382-8888
    hypertech.com

    K&N Engineering
    800/858-3333
    knfilters.com

    Performance Distributors
    901/396-5782
    performancedistributors.com

    Rubicon Express
    866/523-7710
    rubiconexpress.com

    Turbo City
    714/639-4933
    turbocity.com

    Vehicle Specs:
    1999 XJ sport
    4.6L
    aw4 auto transmission
    4.88 gears
    33-inch tires
    Power Gains:
    stock: 152 hp, 200 lb-ft*
    Modified: 172 hp, 224 lb-ft*
    *Note - numbers taken at rear tires right around the 10,000-mile mark-after swapping from our 4.0l to the 4.6l engine-we lost a few lobes on the camshaft. during the subsequent

    August 2006, P. 64

    Full-Mambo Dyno Tune
    Power Play Combo:
    Golen Engine Service 4.6l Long Block
    Banks Torque Tube
    Dyno Shop Chassis Dyno Tune With
    Unichip Controller

    Right around the 10,000-mile mark-after swapping from our 4.0l to the 4.6l engine-we lost a few lobes on the camshaft. during the subsequent cam replacement, we noted that the header had cracked, so we installed a new Banks torquetube and took our 4.6l back to the dyno shop to have the crew professionally dial in the air/fuel ratios under simulated driving conditions on the chassis dyno. Dyno tuning is both an art and a science and is the only real way to ensure the best driveability under any load condition. the dyno shop used a unichip piggybacked onto the stock eCu to properly manipulate the ignition and fuel tables. since we installed a different header we had the dyno shop establish a new baseline for our stroker combo. The horsepower remained the same, but we saw a 5 lb-ft improvement with the Banks torquetube. in addition to the higher power numbers, dyno tuning offers far superior seat of the pants driving impressions since power across the entire rpm band is increased, as well as throttle performance.

    Vehicle Specs:
    1999 XJ sport
    4.6L
    AW4 auto transmission
    4.88 gears
    33-inch tires
    Power Gains:
    stock: 172 hp, 229 lb-ft*
    Modified: 184 hp, 235 lb-ft*
    *Note - numbers taken at rear tires

    Sources:
    Accel
    888/Mr-GasKet X999
    mrgasket.com

    Banks
    800/601-8072
    bankspower.com

    The Dyno Shop
    619/562-3933
    thedynoshop.com

    Golen Engine Service
    800/591-9171
    golenengineservice.com

    K&N Engineering
    800/858-3333
    knfilters.com

    Performance Distributors
    901/396-5782
    performancedistributors.com

    Rubicon Express
    866/523-7710
    rubiconexpress.com

    Unichip
    www.unichip.us

    November 2005, P. 90

    Nitrous!
    Power Play Combo:
    Golen Engine Service 4.6l Long Block
    Nos Powerfogger Kit, PN
    05130nos

    Nitrous oxide is one of the hardest-hitting power adders out there. Asking no quarter and leaving no mercy, it shoots massive quantities of oxygen molecules into the engine, allowing proportionately massive quantities of fuel to be burned. The results are immediate, but if you don't follow certain protocols, so too can be the consequences. Follow the system's installation instructions and make sure to pull back the timing 2-3 degrees for each 50-75 hp of spray to prevent detonation. run premium fuel (you may even want some octane boost) and check your air/fuel ratios with a meter if possible. we installed an nos powerFogger kit, pn 05130nos on our XJ's 4.6l stroker early in the engine's life to see what sort of power we could make on the bottle. we dialed the system in for a 75hp shot and hit the dyno shop to see what the results would be.

    Sources:
    The Dyno Shop
    619/562-3933
    thedynoshop.com

    Golen Engine Service
    800/591-9171
    golenengineservice.com

    Nitrous Oxide Systems (Nos)
    A Division Of Holley 270/781-9741 (Tech)
    800/Holley-1 (Nearest Dealer)
    nosnitrous.com

    Vehicle Specs:
    1999 XJ sport
    4.6L
    aw4 auto transmission
    4.88 gears
    33-inch tires
    Power Gains:
    stock: 184 hp, 235 lb-ft*
    Modified: 245 hp, 372 lb-ft*
    *Note - numbers taken at rear tires

    July 2006, P. 46

    4.0L Cam Upgrade
    Power Play Combo:
    Comp Cams Xtreme 4x4 Cam, PN 68-232-4

    For most average Jeep enthusiasts, a cam swap seems like a daunting undertaking. Most are content to slap part after part on the outside of their engines, but few seem to want to crack into the greasy innards to get at the heart of the beast.

    The factory cam is puny. there, we said it. Just a simple cam swap can really bring up the torque, power, and drivability of even a stock Jeep. to prove our point, we searched out a dog of an '89 XJ with the factory remix injection, over 130,000 miles on the clock, and its full complement of factory widgets and smog gizmos. all we did was plop in a Comp Cams Xtreme 4x4 flat tappet cam in place of the factory jobbie. the Comp Cams pn 68-232-4 that we used is intended for stock-type injected applications. with an advertised duration of 250/256 degrees and lift of .460/.476, it's civilized to be sure. But it woke up our stocker to the tune of 12 hp and 18 lb-ft. not bad for an investment of a couple hundred bucks.

    Vehicle Specs:
    1989 XJ Cherokee
    4.0L
    AW4 Auto Transmission
    3.55 Gears
    28-Inch Tires
    Power Gains:
    Stock: 93 Hp, 147 Lb-Ft*
    Modified: 105 Hp, 165 Lb-Ft*
    *Note - Numbers Taken At Rear Tires

    Sources:
    Comp Cams
    800/999-0853
    compcams.com

    Westech Performance
    951/685-4767
    westechperformance.com



    July 2007, P. 44
    Centrifugal Booster
    Power Play Combo: Adventure Innovations 4.0L Supercharger System

    Some time ago, Cappa flew out to shoot the install of a then-new supercharger system for the Jeep 4.0l. the company, adventure innovations, now has intercooled centrifugal supercharger systems for the Jeep 3.8l, but we shot the company's system for the good old 4.0L.

    The adventure innovations unit mounts the centrifugal blower on the passenger side of the accessory drive and relocates the alternator down and out of the way. the factory air box is removed to make way for the intercooler and new air intake. the factory in-tank fuel pump and pressure regulator stay in place, but an additional pump and boost-referenced regulator are mounted to the passenger fender under the hood to augment the fuel supply. in addition to all the hardware, a calibrated unichip is programmed to combat detonation under the unit's designed 5-6psi boost and piggybacks on the factory ECU.

    Sources:
    Adventure Innovations
    805/322-7001
    adventure-innovations.com

    Vehicle Specs:
    2005 TJ Wrangler Unlimited Rubicon
    4.0L
    Nv3550 Transmission
    4.10 Gears
    33-Inch Tires
    Power Gains:
    Stock: 129 Hp, 159 Lb-Ft*
    Modified: 202 Hp, 227 Lb-Ft*
    *Note - Numbers Taken At Rear Tires