The “Lowdown on Jeep Six-Shooters” (Apr. ’18) article is very interesting, thank you. I have a ’08 four-door Jeep JK Rubicon. I did not realize the poor performance of the 3.8L until I installed 35-inch tires.
I have a couple of questions regarding the 3.8L. You mentioned that installing any power-adding items is asking for trouble. What power-adder items are you referring to?
I’m very much interested in an engine swap. My concern is meeting the emissions standards for a state like Utah when installing an LS or a Hemi V-8?
Thanks again for the article and your insight. James Cox
Via email Trent McGee replies:
Thanks and I’m glad you enjoyed the article! The 3.8L isn’t a bad engine per se, it’s just not a great one. Much like the minivans that they primarily powered, the 3.8L is adequate for the job but entirely unremarkable. By power-adders, I was referring mostly to forced induction. Unlike the Pentastar, the bottom end of the 3.8L was never designed or intended for use with a turbocharger or supercharger.
There are kits that exist to add that stuff to a 3.8L, but reliability suffers. It’s pretty well proven that 3.8L engines don’t deal with hard use very well, and forced induction just places more strain on already marginal internals. It’s my opinion, and that of many others. Trying to wake up the 3.8L is filled with potential pitfalls. Things like headers and a cold-air intake certainly don’t hurt, but I personally haven’t noticed much of a gain adding that stuff as you do on some other engines. The bottom line is this: treat it nicely and maintain it, and it’ll probably go 200,000 miles or more. Beat on it a lot or throw a supercharger on it, and don’t be surprised if you end up with holes in the block where they don’t belong.
As for engine swaps, both Hemi and LS swaps are well documented and supported. LS engines are physically smaller and therefore a bit easier to place in a JK engine compartment, but both are very viable options and can endure a lot of abuse without much issue. I’m not intimately familiar with Utah emissions and therefore can’t speak intelligently on what may or may not fly. I would
recommend talking to a local shop that has done a few swaps and see what they say. If you’re in the Salt Lake area, talk to John over at Impulse Off Road (impulseoffroad. com). He’s a good guy and could probably help you weigh your options for Utah emissions.
I hope this helps, and good luck with your Jeep project!