I have a 2011 Rubicon Unlimited with the 3.8 engine and 4-speed auto tranny. It’s outfitted with 37” IROC ND’s with 5:13 gears, a 9,000lb winch, aluminum wheels, skids and bumpers – and add camping gear, guns and ammo, and it’s no wonder I need more power! Low end power offroad is great. But on the highway it’s horrible. Even with the 5:13’s and a Superchips tune, trying to stay at 70-75mph on hills is impossible and the tranny kicks out of overdrive sending the rpm’s to the moon.

After lots of consideration and calls to people who know more about JK’s than I do, I decided to start adding power slowly by installing some headers first. Depending on the gains from the headers, my next step would be to install a supercharger. I’ve read and have been told that short tube headers do nothing for performance, so I opted for the RIPP long tube header kit which includes two options – a Diablo RIPP Header specific tuner and a HushPower resonator. You can just buy the headers and not the options, but what the hell, I went all in.

The Install:

The RIPP directions are easy to follow and their customer tech support was great. RIPP says it takes 4-5 hours for a competent shop to install but it took me all day with breaks for a few beers. I’ll admit I took my time and checked everything a hundred times. I’ve heard the horror stories about broken bolts on the JK manifold, so I sprayed the manifold bolts down with liquid wrench for two days prior to attempting to remove them. I’m not sure it helped, but all the bolts came out easily. The kit doesn’t come with new header gaskets and RIPP says to use the old ones. Mine looked questionable so I ordered new Mopar ones from Rock Auto. The left manifold had a slight crack I didn’t know about, so I guess installing the headers was a blessing since the cracked manifold would have to be replaced anyway. From here, I just followed the directions and the kit installed easily and it matched to my MBRP offroad exhaust perfectly. RIPP says to re-use the old O2 sensors, but I opted for new ones. When installing the sensors use anti-seize on the threads so if they go bad down the road you can get them out. From experience I can tell you they can be a bitch to remove. The RIPP headers throw some serious heat, so make sure all the O2 wires are well out of the way of the headers and pipes, or they’ll melt. The directions say to retain, trim and use the OEM heat shields off the stock manifolds. DO NOT SKIP THIS step or you’ll torch the plastic spark plug boots and wires. The RIPP tech told me to use some spark plug heat shield boots as an extra precaution, so I got the DEi heat shield boots from Amazon cheap. I didn’t install the HushPower resonator at first because I wanted see if it was going to be loud without it. Yep, it was loud. Crazy loud. I knew the wife wasn’t gonna have any of that so I installed the resonator. It takes a bit of measuring and cutting (of your existing exhaust piping) to install the resonator, but nothing too hard. The resonator is placed just after the muffler, which leaves plenty of room between the muffler and the first bend of the pipe before it goes over the rear axel. On 4-doors, you might have clearance issues with the evap canister, but by turning the resonator sideways to its shorter width side gives you plenty of space. RIPP suggests to weld the resonator on, which I did, but it can be bolted on. With the resonator installed the sound difference is amazing! The headers still sound cool, but they’re way quieter and there’s no droning.

The header install completed, I shifted to the Diablo RIPP header specific tune install. The Diablo tuner must be updated on your computer first, which I did. But when I went to tune the Jeep the menu options weren’t all there. A quick call to Diablo and they updated my tuner from their computer to mine. This tuner gives you two specific header tuning options, one for a 89 octane tune and one for a 91 octane tune. I chose the 91 tune – which means you can run any fuel from above 91 octane to 91 octane – but nothing below. If you’re in states where there’s not many 91 options at the pump, a quick tune to 89 is easy - which is why I carry the tuner with me - especially on long trips through different states. The Diablo tuner also lets you set the tire size to recalibrate the speedo, but it offers very few other options that my Superchips tuner does offer. But again, what you’re really paying for here is the Diablo RIPP specifc tune to add header/engine performance, and not really all the other options like Superchips. Fine. That said, Diablo tech support was super helpful.

After the tune was complete, I did a test drive and soon the check engine light came on. Damn! The Diablo tuner doesn’t have a check codes option to diagnose the issue. I used my Superchips tuner and I found that the Jeep was firing off as many codes as the Democrats are firing off impeachment threats! I had 7 codes I never had before! All the codes were related to the bank 1, sensor 1. That’s the passenger side sensor on the header just before the cat. It was one of the new Bosch sensors I bought and I’ve heard they were tempermental. A quick order of a new Mopar O2 from Rock Auto saved the day. All the other Bosch sensors were OK so I left them alone. After a fifteen minute install of the new sensor, I was able to clear all the codes and say goodbye to the check engine light. I continued to use my Superchips tuner to turn off the TPMS and do other mods not provided in the Diablo tuner. I have no idea if I should have used both tuners, but I can tell you after a few hundred miles the Jeep runs perfectly. Seems like both tuners and the Jeep computer are playing nice! Time will tell.

Performance:

Ripp says that on average you can expect 35lbs/ft of torque, 600 RPM sooner than stock, and 25 rear-wheel HP gains with excellent response throughout the RPM range. I didn’t run a dyno test because for me, the only real test is the real world. As far as added power? It’s pretty good, but not great. I do have consistent power along the entire rpm range. It’s a little more responsive off the line and overall the power is noticeable. I can honestly say my Jeep now stays in OD on the hills and it doesn’t kick down like before. Actually, it cruises at 80mph quite nicely now too. I went from 15.6 mpg to 17.7 mpg – that’s at 70mph on a flat to semi-hilly highway over a driving period of one hour. I didn’t expect this gain and it wasn’t an objective. I doubt you’ll see this gain in mountain areas. Overall, the power gains are enough that I’m now on the fence about installing a supercharger. If I lived in a more mountainous state I wouldn’t hesitate one second. But for my trips out west a few times a year to go offroad, I can probably live without a supercharger. Well, maybe.


I hope this short write-up helps you 3.8 guys!