Welcome to part two of our 5.9L Dodge Magnum V-8 engine conversion. Last issue we gave you the breakdown on all of the critical parts and pieces needed to get the 360 into our ’97 Jeep Wrangler. This month we’re wrapping up the relatively easy engine swap and testing the results of our ’99 Dodge Durango powerplant. Like most project vehicles, our ’97 TJ has been a fun, but very labor intensive build.
Luckily, we’ve had the help of the fabrication and all around 4x4 experts at Off Road Evolution in Fullerton, California, to aid us with our Wrangler’s transformation. Though not all engine swaps necessitate a top tier install shop, they do require lots of planning, problem solving, and above all, patience. For our engine swap everything went together well with the exception of an electronics issue that turned out to be a faulty ECM (electronic control module).
Though we did figure out the issue, it took the brain storming of the EVO crew along with a few phone calls to wiring experts at Hotwire Auto to pinpoint the culprit. Our best suggestion for this or any engine swap is to not be afraid to ask an expert and do your research. Another valuable piece of advice is to leave the wiring portion up to the pros. Sure, you might pay a little more to have the harness spliced for you, but having the ability to basically plug and play (and not worry about a missed or chafed wire) will save you a tremendous amount of time, money, and frustration in the long run.
Living With a V-8
A V-8-powered TJ sounds like the recipe for a terra-chewing rocket. And while the effects of our 5.9L would be more dramatic in a stock Wrangler platform, our modified TJ on 37’s feels strong, but not overly impressive. Even with 4.88 gears, the on-road power is good, but don’t expect to be taking any Vipers off the line. In hindsight, the Jeep may have benefited from a lower stall torque converter—or we could have dropped in an NV3550 for more efficient power transfer.
The power in low range and off-road is great and we even have enough power to play in the sand and desert in two-wheel-drive. Since the conversion we’ve taken the Jeep as far west as the Johnson Valley, California, Hammer trails and as far east as the muddy backwoods in the Carolina. Overall, the 5.9L has helped make the Jeep a more versatile vehicle, and that’s precisely what we wanted. Though we haven’t hooked up the A/C yet, the engine heat transferred to the inside of the cabin of the Jeep feels no warmer than the factory 2.5L, and we haven’t experienced any overheating issues from the engine thanks to the Advance Adapters radiator.
To find out exactly how much power the Jeep is putting down at the rear wheels we took it to the tuning pros at National Speed in Wilmington, North Carolina. Using their Dyno Jet diagnostics machine we strapped the TJ in and went for a couple of runs. The results, sadly, were not all that impressive. In fact, we peaked at 166 horsepower and 233 lb-ft of torque. While part of our problem was that the Jeep was running a little rich and the computer wasn’t going into open-loop, the real issue was that we have a 12-year-old engine, automatic transmission, and heavy 37-inch tires.