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Thread: Does someone make a kit to put a GM LS engine in a JK?

  1. #1
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    Default Does someone make a kit to put a GM LS engine in a JK?

    The wife has given me the go ahead to start shopping for a JK, since my XJ is getting tired. I don't like the price of the new ones, and I've tested the 3.7 in the new Grands. It didn't do much for me.

    Thinking used 07', and 5.3 LS swap. I have the cash saved for a '07-08 JK, but would have to take a partial loan to cover an '12 with the new engine. Then, I'd be tied to a warranty limiting mods. I've done swaps before, so I know what is involved, just wanted to know if there are kits to position engine, mate trans or t-case, etc. I've googled, but LS swaps only seem to come up for TJs. I don't really care for the Hemi engine.

    Thanks for the help.
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  2. #2
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    Depending on your location and budget, you could just drop it off at Teraflex and get a Hemi dropped in it, not cheap though. You could always just google "LS JK" and see what comes up.

  3. #3
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    I would love to follow a thread on this

    http://www.jk-forum.com/showthread.p.....-need-help!&
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  4. #4
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    The problem to overcome is the incompatible computers. I have not read of any successful finished LS instals, only a couple of starts and in progress reports, all pointing to the same issue.

    The JK's are all fly by wire now, where the TJ's were not. EVERYTHING on a JK is computer run.

    On the other hand, the Hemi swaps work great and there are several companies that do turn key conversions or offer do it yourself kits. From what I read, about the lowest cost Hemi conversion that actually works and has all of the required features is a do it yourself swap using the AEV premium kit, which includes needed parts or gives the Chrysler/Jeep parts numbers for them. They also provide guidance on which used engine to select. My SWAG on all in costs for a do it yourself swap is ~$10k, maybe a couple of $k's lower. Burnsville Offroad also offers kits, but there seem to me to be too many overheat issues.

    Turn key conversions to the 5.7 VVT Hemi run from roughly $15k to roughly $22k or so. More for the 6.1 Hemi and more yet for the 6.4 VVT Hemi.

    I have a 5.7VVT AEV conversion done turn key. Looking at it you wouldn't know its not oem. Driving it is great. I have ~22k miles on it with absolutely no issues.

    Another alternative that you might find attractive is a RIP supercharger. I believe they are on Gen II or III and seem to have the bugs worked out. They use a centrifugal pump and not as much torque down low as a Hemi but apparently the improvement is significant.

    Avenger offers a Roots style blower but their kit isn't really end user ready I think.

    So for the foreseeable future, choices are 3.8 as is, with a supercharger, Hemi or the 3.6.

    If the Hemi isn't for you then I'd suggest waiting to try a '12 with the new 3.6, which is reported to come with 88 more hp and about 60lbs' more torque than the current '07-'11 3.8. More importantly to me is that the auto '12s will come with the 545rfe five speed transmissions rather than the current 42rfe four speeds, which have too large a jump from 1:1 third to .67:1 O/D fourth. To many drama filled downshifts with the 3.8's power and the too steep a jump to top.

    There are plenty of dealers that are mod friendly - and plenty that are not. You don't list your location but I can think off hand of three very mod friendly dealer, one near Pheonix, AZ; one near Columbia, SC; one in Balitomre, MD with another location in Annapolis, MD. There are plenty more, you can find some of them through JKOwners.com.

    JPK
    Last edited by JPK; 06-03-2011 at 08:31 PM.

  5. #5
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    Quote Originally Posted by JPK View Post
    The problem to overcome is the incompatible compters. I have not read of any successful finished LS instals, only a couple of starts and in progress reports, all pointing to the same issue.
    Weird. Maybe it's just because of how the smog laws work here in California (you have to swap EVERYTHING emissions related from the donor to the recipient in order to be legal, including the ECU), but when we do swaps out here, we always just assume you'll swap the ECU and entire wiring harness. It's not a big deal if you just do it all together. Some guys go through the trouble of separating the unused stuff from the loom, some don't. And guys out here are putting LS engines into EVERYTHING. LS-powered Jeeps, meh - We got LS-powered Miatas and RX-7s. The first time you see one of those, it gets your attention.
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  6. #6
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    there is no kit currently available to do the swap your talking about, just the ones mentioned previously regarding the hemi swap from AEV or burnsville.

    i happen to own a AEV hemi tj and it is an absolute monster to drive but also very docile around town and has a factory fit and performance to it. never runs over 210 temp no matter how hot it is outside. If your after reliability then AEV is the answer for what your looking for. Their harness is OEM quality and was actually built off one of Chrysler's peg boards. For the JK the programmer that comes with the kit lets you calibrate for tire size and gear ratio change which is a important function.

    If you are interested the VVT is the choice to go with, much better power and torque curve and better gas mileage to boot. with the VVT you'll be around 380-400 hp at the motor depending on what year motor you use and out of what vehicle.

    drop me a pm if you have any questions.
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  7. #7
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    I know jeepspeedshop dot com is working on the LS conversion. I've driven a 5.7 VVT and 6.4 VVT hemi and those things are the bomb. Tire smokin neck jerkin good times! So much so I've got Nemesis Industries (Burnsville Offroad West) working on a 2011 Rubicon 5.7 VVT for me right now. It should be done in a few weeks. They do beautiful work. BOR also does complete kits for the do it yourselfer. The problem now days is the computer is so integrated into the vehicle. Not like the old days of sticking a 350 into a YJ.
    Cheers,
    John

  8. #8
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    Quote Originally Posted by Herbie View Post
    Weird. Maybe it's just because of how the smog laws work here in California (you have to swap EVERYTHING emissions related from the donor to the recipient in order to be legal, including the ECU), but when we do swaps out here, we always just assume you'll swap the ECU and entire wiring harness. It's not a big deal if you just do it all together. Some guys go through the trouble of separating the unused stuff from the loom, some don't. And guys out here are putting LS engines into EVERYTHING. LS-powered Jeeps, meh - We got LS-powered Miatas and RX-7s. The first time you see one of those, it gets your attention.
    It isn't the smog laws, its the basic operation of every feature of the new JK's. Without the Chrysler/Jeep ECU even the radio controls don't work, let alone door locks, ESP (Electronic Stability Program,) antilocks, TPM (Tire Pressure Monitoring,) etc. The Chrysler/Jeep system is incompatable with the GM system, so there is no integration, no add on that works that I have read about, and I look for this stuff.

    Even getting the Hemi to work seemlessly has been a challenge not every would be converter has mastered and that is but one reason picking a good conversion kit is important. For that matter installing some of the lower end lifts can be fraught with ECU challenges, with the dash board lighting up like a Christmas tree, the ECU throwing codes and the ESP kicking on.

    As far as smog laws go, California has the tightest. MD has followed California's lead, but when the tester is plugged into the OBD port the AEV Hemi conversions will pass.

    BTW, federal regs require an engine of the same year or newer be installed for swaps.

    I have a 6.0L powered Suburban. The Hemi is every bit the equal, really more, though .3L smaller. Where GM shines and Chrysler/Jeep doesn't is in auto transmission programing. The auto in my Suburban is always in the correct gear and when it shifts up or down you know why and it does it at the right time. Once in a while the Chrysler transmission programming will leave you wondering why it up or down shifted. But that happens infrequently and it isn't a big deal.

    I love my Jeep with the 5.7 VVT in it and if it was totaled tomorrow I'd be back on the phone with AEV for another 5.7 VVT.

    BTW, I've driven an AEV 6.1 Hemi powered Jeep. All AEV Hemis are autos with the 545rfe and mine runs on 37's with 4.88's, that Jeep was on 35's with 4.88's so you would expect more performance just because of the smaller tires, but the difference was pretty significant. That one had enough to burn the 35's from a dead stop, no wind up just hit the petal, at least until the ESP program caught up and dropped revs.

    On the other hand, the one fellow who I know has had both the 5.7 VVT and the 6.1 hated the 6.1 and loved the 5.7 VVT. AEV recommends the 5.7 VVT and told me that the 6.1 has a flat spot right where you wouldn't want one and didn't produce the torque down low that the 5.7 VVT does. I only drove the 6.1 for maybe fifteen minutes and only on the road but I didn't notice the shortcomings. The 6.4 is also a VVT engine and is supposed to have the same torque and HP curves as the 5.7 VVT but just more, lots more. The 5.7 VVT is plenty enough. {Edit to add that EVERY Hemi has more torque at 1200rpms than the oem 3.8L puts out at max, which is what makes them so fun to drive.}

    My wife has an auto '08 JK Unlimited Rubicon with only a 2.5" BB on it, so the oem 4.10's and 32's along with the 3.8L. The 3.8 power is ok, but the 42rfe four speed is not a good match with too steep a jump from 3rd to 4th. The forthcoming '12+ 3.6L which puts out that 88 extra HP and 60lbs' more torque will be mated to the 545rfe, which has the same 1:1 3rd ratio and nearly the same top O/D ratio as the 42rfe but has its fourth gear right between the 42rfe's third and top gear, which makes highway down shifts drama free - and the Hemi makes them less frequent to begin with. So, with the new five speed and the extra power the 3.6 offers, the 2012 JK's might just make Hemi swaps more rare.

    JPK
    Last edited by JPK; 06-04-2011 at 04:00 AM.

  9. #9
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    Quote Originally Posted by Herbie View Post
    Weird. Maybe it's just because of how the smog laws work here in California (you have to swap EVERYTHING emissions related from the donor to the recipient in order to be legal, including the ECU), but when we do swaps out here, we always just assume you'll swap the ECU and entire wiring harness. It's not a big deal if you just do it all together. Some guys go through the trouble of separating the unused stuff from the loom, some don't. And guys out here are putting LS engines into EVERYTHING. LS-powered Jeeps, meh - We got LS-powered Miatas and RX-7s. The first time you see one of those, it gets your attention.
    ever seen an LS powered S2000? now thats an attention grabber. makings of a rocket. read one thread on a forum for the ls2000 swap and one guy had a stock ls motor, nothing special and he had to sandbag the trunk to keep traction
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  10. #10
    There is a 100+ page thread on Pirate4x4.com in the 'Jeep - Hardcore' section of the bulletin board on 5.3 swaps into jeeps. Lots and lots of info there.

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