To start, my Jeep is a '15 with the 3.6/auto trans, and is not a daily driver. It gets used for both rock crawling and for driving ridiculously fast on rough trails/access roads in northern AZ. It's a heavy Jeep, major build specs are in my sig. I wanted to ask about the feasibility of using the GM 480hp LS3 crate engine with the Motech Gen IV LS swap kit. It has the GMPP LS Hot Cam in it and I believe that is the only difference compared to the standard 430hp LS3. It does have a rougher idle and I'm curious if you guys at Motech have been able to tune out much of the quirks that a cammed LS can have.
Some more general questions that are related to the swap. I've looked at the DIY swap kits on the Motech website, and the list of items that come in it. I'd be going with the Premium kit that comes with the xfer case adapter for the 6L80 and aluminum radiator. I'm also planning to do this swap in my garage. When using the LS3 crate engine, is there anything else besides the engine and transmission that I would need? I must use a Sport/Sahara 2.72:1 xfer case instead of my Rubicon 4:1 case correct? I'd like to be able to just use the Jeep JK engine accessories, from what I've read this can be done with the brackets you guys make right? For sourcing a 6L80 trans, do I need one from a car, 2wd truck or 4wd truck, or does it not matter? Is a majority of your newest harness plug and play or is there still a good bit of cutting and splicing that needs done?
Thanks for any help. Planning to accumulate all the parts over the summer months and do this swap later this fall.
The LS3 430 HP engine has good power and drivability. With a few small tune and exhaust changes we are seeing 450 HP at the crank. The advantage the 430 HP engine has over the 495(GM now rates the 480 at 495) is perfect drivability. An LS3 430 HP engine will idle all day on the trail, your wife will be comfortable driving it to the store; it is very much a Dr. Jekyll and Mr. Hyde engine. Mild like a stock engine but comes alive when you get on it. The Hemi and 495 engines feel more pumped up, like a muscle car they never quite relax. You get some rump, rump, rump and HC's at idle. I will say over the years we have an excellent 495 tune that idles well and still runs to 7,000 rpm, it's just not as relaxed as the 430 engine which runs like an Escalade.
You will want to loosen up your torque converter with the 480 HP engine and go to 2 1/2" exhaust. Run high performance converters the 495 engine has high cylinder pressures and will blow out standard cats.
Our new JK billet drive is pretty awesome, it uses the stock 2007-11 JK accessories and puts them back where they were so the original lines, hoses and connectors work. The Pentstar has an odd accessory drive that mounts the alternator backwards, we do use the Pentstar PS pump an compressor in some applications though.
If running the GM CTV accessory drive on an LS3 we find the stock Camaro PS pump works fine with tirews up to 37". For larger tires or hydraulics the Camaro pump does not work well and we have some options including substituting it for a JK or PSC pump while maintaining the stock head mount reservoir. Make sure if running the JK PS pump you run ATF4+ and if running PSC or GM use the mineral based PS fluid, we like the stuff GM sells.
Basically you can run a 241J from any 2007-11' JK manual or automatic. You can run a 241J from a MANUAL JK from 2007-16'. The automatic JK went to a female input on the TC in 2012 so both the automatic J and OR will not mate to the 6l80. We find the 4:1 OR low ratio is too low for general wheeling when combined with the 4:1 first gear of the 6l80. This is a 16:1 low ratio where a stock Rubicon(2007-11) is 11:1. Ironically when you mate a 2.7 241J to a 4:1 6l80 you end up with virtually the same low ratio as a stock Rubicon and it works perfect. You can get wheel speed up with the J TC for mud, sand and snow where the 4 and 5:1 ratios are better suited for serious crawling and will not work well on trails. With our 241J-6l80 adapter the 241 will handle 500 HP. The 241J is chain driven and has an internal oil pump so it is great on the highway and quiet. With a gear driven TC like the Atlas you need to be careful with proper set up and gear lube. Running a gear driven TC with thick oil behind a 4 cylinder CJ is very different than cruising 80 mph for hours in a 400 HP V8 and a 6,000 pound JK. Clearances and splash oiling must be right and unlocking hubs are desirable. We find the low cost solution the best, 241J with a 6l80. I also really like the Atlas 2 for 2WD low to free up the steering wheel and front wheel drive for snow. The 4:1 front planetary of the early JK's is relatively weak and I would not run it behind a 500 HP LS. I have seen the smaller output shafts of the 4l65's twist off even with 6 liter engines. The 6l80 runs a larger output and once our input gear is installed it's unlikely you will have any issues.
You can run a 6l80 from a 2WD, 4WD or an AWD vehicle. If running a 2WD 6l80 you need to cut off the output shaft and install some seals. We also support the 6l90 but prefer the 6l80. The 6l90 is longer than the 6l80 and has a larger output shaft. The 2 and 4WD 6l90's have different output shafts so the 2WD 6l90 will not work unless you replace it which is a PITA. Stick with a 6l80 if you can.
It's very important you match the transmission and engine. These CAN transmissions have TCM's built in. In general there are three groups of TCM's.
2007-8 will support basically only the early L92 6.2 from Escalade's and Denali's.
2009 a year all by itself and the 2009 6l80 will work in most 2009 engines. The 5.3 got the 6l80 in 2009.
2010+ this is what yoiu want. In 2010 GM increased compatibility between ECM's and TCM's across the board. So if you have a 2012 LS3 you can run pretty much any 2010-16' 6l80 2WD, 4WD or AWD.
https://www.youtube.com/watch?v=8U9zidtjB68
