Overkill was one of the original tuning outfits for the Chrysler 3.6 engine and I tune dozens every month. Your Durango or Grand Cherokee 3.6 can benefit from Overkill tuning just the same as a Charger/Challenger! Overkill tuning revises many items from the factory Chrysler tuning, including spark timing advance, camshaft phasing, fuel targets, removing throttle and fuel enrichment delays and revising torque management interventions. This improves mid-throttle torque in particular, can improve fuel mileage and increases horsepower.

You will receive tuning files for several gasoline grades including 91,93, 87 and 89 octane, as well as running E85 ethanol if your car is flex fuel enabled from factory (Check out our fuel injectors for maximizing E85 ethanol gains). With the HP Tuner suite, you'll also receive revisions to the transmission tune for either the 5 speed or 8 speed automatics, depending on your year.

Independent tests have shows the Overkill tune doubles the performance gain over the preloaded Diablo tune using dynos or acceleration performance tests. One customer dyno tested the Overkill E85 Tune at 267whp vs 238whp from Diablo preloaded tune, a 29 wheel horsepower gain.


HP Tuners Suite: Tuning for your Durango/Grand Cherokee 3.6 is provided through the HP Tuner's suite. This tuning suite requires you to have a laptop or tablet running Windows. You'll be required to read and write the tunes to the vehicle using the suite but all the tuning work is provided from Overkill. A few clicks and key turns and you're tuned in a matter of minutes. The suite is yours to keep ($399 value!)

Important Note for 2015 and newer Tuning: For 2015 and newer Chryslers, a computer modification is required to become tunable. You must remove the computer from your vehicle and send it to HP Tuners for modification. This is a $250 charge that involves a separate transaction with HP Tuners, it is not through Overkill. There is no way around this!! I wish there was, blame FCA. Once you get back the computer module, Overkill will be able to write Overkill tunes using the now unlocked factory programming from HP Tuners. See more on this service here https://www.hptuners.com/product/pcm-modification-service/

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Any Performance Mods?

Already have an HPTuner suite? You can purchase Overkill tune files with ongoing tuning support below, you'll get 87, 91 and 93 octane tunes programmed for your current modifications. You'll need to send a factory read file to willoverkill@gmail.com in order to receive back your Overkill tunes, once you've made your purchase below.

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If you already have a Intune or Trinity from Diablosport, upgrade it by purchasing Overkill tuning. You'll get all the Overkill tune files that we include when buying the Diablo device from us, plus custom datalogging tuning services. Overkill tunes load to your vehicle just like the Diablosport preloaded tunes. Once purchased below, send both original backup and last tune written files from your handheld to willoverkill@gmail.com to receive your Overkill tunes back. You'll do this by plugging the device into your PC and you'll find a Tunes folder on the drive with the files that are needed.

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Any Performance Mods?

If you want to run E85 ethanol, it's highly recommended to upgrade your fuel injectors. The factory units we've found they can max out their capacity as soon as 5500rpm, leaning out the engine beyond that point and robbing power. These 39# fuel injectors will provide the true capacity required run E85 and will improve horsepower at higher rpms while running E85. Once tuned you can run gasoline as well with no issues, but the gains are when running E85.

Tuning is required to install these injectors. They are genuine Bosch brand and a direct replacement to the factory injectors.

Want some improved performance from your Pentastar, here's my suggestion:

Want some easy horsepower? The lower intake manifold from the Pacifica's updated 3.6 Pentastar motor is an upgrade to older Pentastars. It features much smoother transitions and doesn't have the pinch area that we used to port out of the older Pentastar manifolds. Dyno tested, this is worth a quick and easy 10 horsepower improvement.

This manifold can be had using part number 5281803AA in the $130-150 range from a Chrysler parts supplier or your local dealership, just be patient if they're backordered. Since the fuel injectors are in the lower intake manifold, great chance to upgrade to the 39# injectors for E85 use while you're in there!