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Powerful Jeep Engines - 10 Proven Power Plays

Posted in How To: Engine on April 1, 2008 Comment (0)
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Powerful Jeep Engines - 10 Proven Power Plays
Photographers: John CappaJohn Sweetser

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

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