CSM19Z5M

Need some help. Was planning to put a Gen IV 5.3 in my 2008 JKU. Motech has a great kit available to do so. Looking for an engine I found a Gen V 2014 5.3 L83 and 6L80E transmission from a Silverado with 12K on it at a can't pass it up price. Unfortunately, none of the conversion company's support the Gen V motors as yet. The primary differences between the Gen V and earlier Gen IV is in the front accessory drive arrangement and the PCM programing. Motech tells me they are not fielding a Gen V kit until late this year. I could sell the engine and buy a Gen IV crate engine but really want to try to make this work first. Has anyone out there installed one in their JK as yet? If so I would appreciate talking to you. Thanks.

BetterInTheWind

Sorry can't help you out with the knowledge, but I'm gonna sub this thread cause I wanna know too!

CSM19Z5M

FYI. I decided on a different route due to time constraints. I bought a Gen 4 LS3 crate engine for the JK. Way more HP than I need but it's reasonably priced and available and there are kits to install it. There is just no satisfactory way to make the Gen 5 stuff work in the JK yet. You can make it run using the GM controller and harness but you can't cleanly integrate the electronics with the JK gauges and other features. Eventually the demand for Gen 5 engines will push the conversion folks who make the kits to offer those kits for the Gen 5 engine conversion but that is probably a year away according to feedback from the vendors. I am going to use my Gen 5 6L80E transmission with the LS3 though. RPM Extreme is going to reflash it to run with the LS3 engine. Just a note here but if you aren't pressed for time and can wait, I highly recommend the Gen 5, 2014 5.3 L83 engines. They have VVT, AFM, and put out 355 HP on gas and 380 HP on E85 gas. It would be the perfect engine for an all around driving JK conversion. There are always some low mileage ones on EBay. Find one from a 2014 Silverado 4X4 with 6L80E transmission. Great setup as soon as the conversion kits are available.

jedg

Hrm...not sure it's that much better. I'm running an L96 with VVT and 360hp (started there before tuning). Honestly it's the 6L80E that makes the system so amazing. I also kinda wish I didn't have VVT at this point just because I'd have power at a lower RPM. (not that it doesn't at low RPM... hahaha)

CSM19Z5M

Yes but you have a 6.0 engine but the L83 is a 5.3 so apples and oranges but I get your message. Both good engines. But they get their added HP partially due to the VVT so it's kind of a double-edged sword. I went to the non-VVT 6.2 for some of the reasons you cited......... low end torque. I pull a loaded M416 trailer all over the country on my expeditions out west every year and needed the mountain climbing power. I hope the gas mileage is "reasonable" Your right about the 6L80 being the key too. It is far and away the best part of these swaps. Would not consider any other AT. Will send you pic's and update when it's finished.

CSM19Z5M

Spent three weeks this summer and installed a new LS3 crate motor and 6L80E transmission in my JK. Went with the RPM Extreme conversion kit which worked very well. All electrical connections through a Canbus. Everything works. RPM was excellent to work with and I got very fast turnaround on my reprograming. Started the engine the first time and not a single code! Now I know how God intended the JK to be powered! My JK had a six-speed stick before the conversion and with the very high (.667:1) over-drive transmission the thing cruises very nicely at 80 @ 1700RPM+/-. My mileage is the same or better than the stock 3.8 was. I am getting about 18-19MPG all around and 24 on the road if I keep it below 65. At 75 it gets 22 with the vehicle loaded heavy. Anyone wanting info on the swap as well as parts lists and prices can PM me. The best source is Jon at RPM Extreme. This is not a cheap swap by any means. The engine was $6k, the conversion kit almost $6k, the used 6L80E with 12K miles cost $1700, and the accessory drive, etc added another $3-4K. But it beats the hell out of a Hemi swap any way you look at it and with far less work. Thanks.

Da20captain

How is an LS swap less work than the Hemi? My Hemi swap was half of what you spent and that included incidentals. Down to the nuts and bolts. True I could only dream of 22MPG's. My rig is pretty heavy. Not that I would get that anyway. But did not do it for MPG's. Reading some LS swap threads is a huge reason I went with a Hemi. Plug and play. I am not a mechanic and this was my first undertaking of anything like this. I had changed a starter and oil.

Congrats on the V8 power!

BRinSCupstate

Sorry, but I don't believe the mileage. I have a 6.0 L96. You can't possibly keep your foot out of it enough to get that mileage.

CSM19Z5M

Just my opinion. If your swap was half the cost you didn't buy all new OEM parts to do it. The LS is lighter, has more HP per cubic inch stock, get's better MPG, no mod of the engine compartment was required whatsoever, and the RPM Extreme wiring harness is plug and play and I have tap shift and "tow/haul" with it. The LS3 crate engine is cheaper than the comparable Hemi equal. Other than that ........................
Let's just say we agree to disagree though and leave it at that.

CSM19Z5M

I actually got almost 26 MPG with it for one tank full with car empty and driving very modestly. As you know, the JK aerodynamics are similar to a large shipping crate but under 65mph they do okay. I drive the car all over the country each year and pull a M416 1/4tn trailer and I don't go 4-wheeling other than mountain roads so the car is perfect now. It get's 22mpg with car full of guns and gear right now. I try like heck to drive it with a light foot but the car is completely stock looking and I do like to pass the occasional "fast mover" just for grins.
Have fun with your Jeep.
Mike