Making A Go-Fast YJ
When the Jeep Wrangler YJ first appeared on the market, many thought that it spelled the end for Jeep, and it was easy to see why. The same smog-choked carbureted 258 carried over from the CJ line, but it was backed with a crappy Peugeot transmission, lackluster NP207 transfer case, Dana 35 rear axle, and a front Dana 30 with an axle disconnect. Could you ask for a worse drivetrain?
The good news is YJs can be picked up for dirt cheap and serve as a blank canvas for creative owners. Richard Johnson is one such resourceful individual, although his YJ project took a decidedly different turn than most: He used a burnt-up, salvaged Wrangler as the foundation for a drag racing vehicle. Richard is an auto shop teacher at W.J. Moaut High School in Abbotsford, British Columbia. He helped form the British Columbia Secondary School Motorsport Association in 1992. Since that time he has been teaching students to build vehicles to drive on the drag strip.
Turning fast times at the track requires not only a healthy engine, but the ability to put it to the ground. In order to accomplish that the rear frame horns were removed at the middle of the chassis and moved inboard to keep the 32x14 Goodyear slicks bead-screwed to 15x14 Weld Draglite rims under the sheetmetal. The narrowed frame works in conjunction with a generous amount of box tubing to act as a foundation for the Art Morrison rear four-link suspension and Competition Engineering coilovers. Unlike rockcrawling suspensions, this four-link uses relatively short control arms with geometry optimized for putting power to the ground, rather than provide maximum ground clearance or articulation. When the rear suspension is not enough to keep the tires planted, a set of Art Morrison Pro Stock wheelie bars keep the front tires from getting too far from terra firma. The setup is a proven performer, producing 1.7 g's when leaving the starting line.
Up front, a shackle reversal was performed in order to keep the Wrangler tracking straight at speed. The front leaf springs still run under the 2WD front beam axle that was sourced from a Jeep Comanche truck. The axletube uses standard Dana 30 knuckles and brakes with a 5x4.5 bolt pattern. Skinny 15x3.5 Weld Draglite rims are bolted up to the front axle and capped with 165R15 Kelly Springfield tires. The axle is steered by a manual steering box that was sourced from the same Comanche as the front axle.
The YJ is powered by a genuine Jeep engine. Richard had previously used a Wagoneer with a 401 for the school program. "It wasn't very fast," he admitted, "but it was consistent in bracket racing." The 401 was yanked from the Wagoneer and put into the Wrangler. "We actually have two similar engines," Richard explained. "That way the students can build one throughout the year and still go racing on the weekends." The 10.5:1 compression ensures that the AMC enginecan run on readily-available pump gas.
The bottom end of the 401 is filled with Sealed Power rings and TRW forged pistons attached to the stock rods and crank. A Colt Cams custom hydraulic camshaft works in conjunction with Crane roller rockers that sit in ported factory closed-chamber heads. The Edelbrock Torker intake manifold is good for high RPM power and is topped with a Holley 670 cfm TBI unit that is fed by a Holley fuel pump mounted on the frame rail. An Aurora Electronics ignition lights off the fuel and ensures that the engine is not pushed beyond the 7200 RPM rev limit. The low placement of the engine in the chassis on custom, rigid motor mounts nearly causes the Milodon 7-quart oil pan to scrape the ground.
A large, four-core radiator from the same Wagoneer that donated the 401 sits up in front of the engine. The radiator is fitted with dual Dayco 12-inch fans that keep operating temperatures at the track to around 180 degrees. A Moroso electric water pump takes less power to turn than the stock belt-driven water pump and can be turned off during passes down the drag strip to free up even more power. Also helping to combat the heat are Cyclone headers that are both ceramic-coated and heat wrapped. The exhaust originally dumped directly out of the headers, but SuperTrapp mufflers were added to quiet down the 401 and comply with regulations enacted at some drag strips
Power is routed through a relatively-rare TH400 case with an AMC bellhousing bolt pattern. The three-speed automatic was built by Bill Kondolay of DTT with a TransGo Stage 2 shift kit along with upgraded clutch packs and bands. The Island Torque Converter 10-inch converter produces a 3500-rpm stall speed and uses an aluminum stator with a roller spring race, a furnace-brazed pump and turbine, and steel splines. The back of the case is fitted with a tailhousing from a Chevrolet application for 2WD operation.
The rear axle is a Dana 60 out of a J20 truck that has been narrowed to a mere 33 inches wide by Rearend Specialties and fitted with 35-spline Strange axle shafts with a 5x4.5 bolt pattern to match the front axle. The differential uses 4.56 gears and a Strange spool to put power to the ground. The combination has turned a best of 11.79 seconds at 109 mph, with an astounding 1.46-second 60-foot time. The YJ is mainly used for bracket racing though, with a dialed-in time of 12.0 seconds flat.