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
Turbo 4.0
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
The Insane Inline Partt III
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