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 integrate the Durango and...
To integrate the Durango and Wrangler electronics we sent both harnesses, along with the TJ’s factory fuse block, to the wiring experts at Hotwire Auto.
What returned was a practically...
What returned was a practically brand new harness that was fitted with sensor and plug labels so there was no guessing what went where. The Hotwire harness is literally as plug and play as they come.
Since our TJ is running a...
Since our TJ is running a high-line fender kit we had to find a new home for most of the Jeeps critical electronics. We used the EVO Manufacturing coilover tower to attach our fuse box and ECM and dropped in a battery box from Poly Performance to secure the battery and battery temp sensor. Remember that a good ECM ground is critical as it is what supplies injection pulse.
With limited spacing under...
With limited spacing under the hood we grabbed a K&N filter off of an old project rig and secured it directly to the intake hat. If your TJ is equipped with the factory fenders (non-high-line), you can reuse your stock intake box with just a little intake ducting modification.
To secure the 46RE transmission...
To secure the 46RE transmission in place we modified the factory Durango transmission mount and mated it to the Superlift crossmember mount. This prevented us from having to modify the Superlift belly pan and allowed us to use the factory Durango transmission bushing.
To achieve the correct gear...
To achieve the correct gear selection range we had to modify the 46RE’s transmission cable mount.
We spaced our bracket nearly...
We spaced our bracket nearly 3 inches forwards, but this adjustment amount may vary among model years and transmissions.
To switch overdrive on or...
To switch overdrive on or off you’ll need an aftermarket momentary switch connected to ground, which can be picked up at most parts stores for a couple of bucks. To wire in the switch we simply attached the pre-ran transmission wire that Hotwire provided to one side and then connected a ground wire and routed it to a solid ground source next to the firewall.
Fitting an exhaust system...
Fitting an exhaust system from the manifolds back is nothing short of magic. Somehow we managed to squeeze in a Dynomax high-flow cat and super-short Bullet series muffler (PN 24215). We are very pleased with the tone and routing of the 2.5-inch custom exhaust and especially like the low idle rumble.
Depending on what transfer...
Depending on what transfer case and transmission combo you have the driveshaft lengths will likely need to be changed. We’re running the factory NP231 transfer case with a JB conversions slip-yoke eliminator on our TJ. Given that our wheelbase has been stretched 3 inches and the new length of the Durango powertrain, it was necessary to have our JE Reel driveshafts modified.
Fitting a Dodge 360 V-8 under...
Fitting a Dodge 360 V-8 under the hood isn’t as bad as one might think. Given the range of modifications done to our Wrangler, we’re pleased with the overall accessory and component clearance. We were especially relieved to find that our aftermarket suspension system didn’t interfere with the conversion.
Power Down
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.