We don’t expect you to go digging into your ’07-’11 Jeep’s 3.8L to make major modifications like cam swaps or head porting. Heck, we’ve been told by Jeep engineers (as in the guys who actually build the engines) that the 3.8L isn’t the most durable engine ever and it’s best not to put major power-adders on it like superchargers or turbos. So, what’s the owner of a 3.8L to do? Make the best of what you’ve got, of course. Keep your mods to the bolt-on and plug-in variety, and your 3.8L should serve your Wrangler a long, adequate, vanilla-flavored life.
1. Cold-Air Intake
Like any engine, ditching the restrictive factory air box and ducting and allow ing your engine a huge whack of colder, denser air will improve power and (usually) mileage. Cold air systems are available from a variety of manufactures like Banks, AEM, and K&N to name just a few.
Again, Upping your spark power so you can open up tour plug gap will imporve low-end drivabillity and torque. Usually there's also bonus top-end power as well. For less than $190, Performance Distributors offers its Firepower kit for the jeep 3.8L, which includes a hotter coil and low-resistance, high-performance plug wires.
3. Electronic Throttle
the Sprint Booster plugs into your electronic throttle and essentially opens the throttle blades sooner for more power in the lower Rpms. The factory tailored throttle to open and close slowly to avoid harsh acceleration or deceleration, but the sprint booster offers three stages of throttle enhancement (stock, Stage 1, and Stage 2) to improve acceleration and drivabillity.
At first there weren’t a lot of companies offering headers for the 3.8L engines, but now companies like Gibson, Borla, Rugged Ridge, and even Rusty’s Off Road Products make ’em. Headers will improve exhaust scavenging, which improves low-end torque. Also, Their increased flow translates into Better high horsepower. It's said that the 3.8L headers are more susceptible to leaks than the factory manifolds, so beware.
Perhaps more than any Jeep model (besides diesel-powered), the 3.8L responds well to aftermarket ECU tuners. Some rewrite the ECU and some piggyback onto it, plugging into the OBDII port. Just a couple of companies to whet your appetite include Superchips, Diablo Sport, and Hypertech. Most claim gains of up to 21hp/30lb-ft, but we think that’s optimistic. Still, there is performance and economy to be gained with their use.
It’s simple science; more air out means more air in. And more air means more fuel can be burned along with it. Besides, the factory JK muffler is always getting clunked on rocks and bashed. Several companies like Banks, MBRP, and more offer after-cat exhaust systems, so do some shopping and pick what fits your budget.