Jku Engine Swap options

timsjeep

New member
I did the swap from Motech about 2 years ago. I went with a junk yard L99 (auto version of the LS3) and a 6L80. I am very happy with the jeep but still feel that 4:88's are in my future. Power is not a problem, but the transmission is still not always happy when going up hills. Once it shifts down its off to the races :) but until then its just not totally happy. I think new gears will help that. As for the motor swap, my only regret was not going with a crate motor. Mine had 88k on it when I installed it and now its got 125+k on it and some things have come up in the last few thousand miles. Nothing major, but out in the middle of nowhere, they could be a problem. I have had it on a few overloading trips and just had a few little issues, but nothing I couldn't live with.

That said, if I were to have a 3.6, I would just leave it alone. My 08 JLUR had the 3.8 and around 175k it started having some major issues with burning oil.

Let me know if you have any questions about the swap, I did it in my shop with basic tools. Not too bad, I would do it again for sure.
 

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Buddha.

Lurker
thats how I bought it and I knew it needed it gears when I bought it..............regearing is in the works anyways its still going to be gutless
live ive said Ive driven them with stock tires and its an absolutely terrible experience
Why would you buy a vehicle when best case scenario driving it is a “absolutely terrible experience”?
 

Stroked 550

Adventurer
Why would you buy a vehicle when best case scenario driving it is a “absolutely terrible experience”?
its best case scenario isn't a terrible driving experience ........ its best case scenario is an engine swap so I can actually maintain speed on the freeway
 

Joaquin Suave

OverlandHardware.com
About 10 years ago I pulled the drive line out of my Jeep Scrambler and fitted a Mercedes DE2.9LA innercooled trubocharged Diesel engine from a military special forces "fast attack" Gilindawagon with a wide-range Getrag gearbox mated to an Atlas wide-range T-case. I've put 10's of thousands of perfect fun miles on her (including 4 over month long solo trips into Baja). She was the "bomb" except when I got some bad fuel south of the border a couple of times, and she went into limp mode!
Then I got with my close friends down at DIESEL INJECTION SYSTEMS in Santa Maria (They are the REAL DEAL) and we made a hybrid pure mechanical pump for the motor (they did the calibrating and I 5 axis NC machined all the bits and pieces) !!! It turned out better than my wildest dreams! I netted about 120 more HP and it takes off like a monkey with its tail on fire. It is so fun... It is like driving the cross between a Swiss watch and a farm tractor. :)

With the electronic pump!
before pump.jpg


With the mechanical pump!
after pump.jpg

vestabule.jpg

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Buddha.

Lurker
I’m surprised the Jeep guys are having problems with the 3.6. My new work truck, a ram crew cab has the 3.6l and it’s not any slower than the 3.5l tacoma it replaced.

I would think a supercharger kit would be the easiest way to get more power, and you could remove it and put the Jeep back to stock easier.
 

Stroked 550

Adventurer
After looking into this myself there are very few options I thought were bullet proof and would be long lasting. I looked at doing a Ripp supercharger. However I am kind of a naturally aspirated fan. I looked at doing the 5.7 Hemi with my 6 speed manual and that was what I liked the most. The horsepower increase with the correct tire size and gearing this would be a very good upgrade to the JKU on paper. However the cost is very prohibitive for me. I decided to put my rig on a diet and regear to 4.88. I am not going to win any races but that was not the point of my rig

I was considering the Ripp supercharger as well but from the researched Ive done it seems to kick on in the higher rpms

how early does it start pulling? how much of a difference does it make?
 

NatersXJ6

Explorer
My 3.6 2014 definitely struggles to maintain speed on freeways, especially at altitude or with winds. It is very happy cruising at 55-60, but you notice how much it is suffering if you make run like I-15N from the AZ strip to 70, it is a fight the entire way. Typically this results in long times at higher RPM and shortly after that you get to change an oil cooler or watch the Jeep burn to the ground.

I’ve assumed this is normal for the 3.6 JK but also heard many people say their 3.6 in Charger, Ram 1500, Minivan, is just awesome. I recognize that aerodynamics has significant influence, as does rolling resistance, and maybe subconscious dread of running too high too long and eating another oil cooler, but could there be something wrong?

I’m also considering that my other recent vehicles have been big gas V-8, or Big turbodiesel V-8, and my expectations might be off.

Opinions? Clearly the OP has similar issues to mine.
 

Stroked 550

Adventurer
My 3.6 2014 definitely struggles to maintain speed on freeways, especially at altitude or with winds. It is very happy cruising at 55-60, but you notice how much it is suffering if you make run like I-15N from the AZ strip to 70, it is a fight the entire way. Typically this results in long times at higher RPM and shortly after that you get to change an oil cooler or watch the Jeep burn to the ground.

I’ve assumed this is normal for the 3.6 JK but also heard many people say their 3.6 in Charger, Ram 1500, Minivan, is just awesome. I recognize that aerodynamics has significant influence, as does rolling resistance, and maybe subconscious dread of running too high too long and eating another oil cooler, but could there be something wrong?

I’m also considering that my other recent vehicles have been big gas V-8, or Big turbodiesel V-8, and my expectations might be off.

Opinions? Clearly the OP has similar issues to mine.
I live at altitude imagine how I feel everyday lol .... thats exactly it my engine spends so much time at high rpm struggling to go up the hills I feel bad driving it as its being so overworked

your expectations are not off, jeep just failed to give us well equipped engine options... it took them what 80 years to give us a diesel option thats just silly

Look at what Ford is doing with the Bronco they have multiple engine options with much higher horsepower so you can actually merge onto the freeway...
The new bronco is probably going to wipe out the jeep sales with everything they offer.
 

NatersXJ6

Explorer
I live at altitude imagine how I feel everyday lol .... thats exactly it my engine spends so much time at high rpm struggling to go up the hills I feel bad driving it as its being so overworked

your expectations are not off, jeep just failed to give us well equipped engine options... it took them what 80 years to give us a diesel option thats just silly

Look at what Ford is doing with the Bronco they have multiple engine options with much higher horsepower so you can actually merge onto the freeway...
The new bronco is probably going to wipe out the jeep sales with everything they offer.
My 2018 expedition with the 3.5 turbo spanks the Jeep routinely. I would gladly do that swap if it could be done. Of course, having 5 more speeds in the transmission helps!
 

Stepsride

New member
Being a supercharger typically the power comes in toward the lower end as opposed to a turbo which come in on the higher end. The 3.6 does not start making torque or HP until the upper RPM. The Ripp will definitely get you off the line faster and the power will be in the lower end of the RPM. THere are plenty of Youtube and Ripp videos to show you the specifics. It depends if that is how you want to go. I know 2 people with Ripp Superchargers and they love them. They have driven from Fl to Colorado without any issues. The benefits of the supercharger definitely helps in higher elevations as well. I am trying to keep this basic as can be. Do your research there is plenty out there for and against. You decide
 

Jnich77

Director of Adventure Management Operations
Being a supercharger typically the power comes in toward the lower end as opposed to a turbo which come in on the higher end. The 3.6 does not start making torque or HP until the upper RPM. The Ripp will definitely get you off the line faster and the power will be in the lower end of the RPM. THere are plenty of Youtube and Ripp videos to show you the specifics. It depends if that is how you want to go. I know 2 people with Ripp Superchargers and they love them. They have driven from Fl to Colorado without any issues. The benefits of the supercharger definitely helps in higher elevations as well. I am trying to keep this basic as can be. Do your research there is plenty out there for and against. You decide

Actually, you can set up a turbo to start building boost and making HP at what ever RPM you want and unlike a supercharger you can "adjust on the fly."
 

timsjeep

New member
My brother has a 2014 with the 3.6 and a turbo and I have to say its pretty impressive. I don't like turbo lag, but once that is over its a beast for sure. Gets good gas millage too, of course compared to my 6.2 that's not a surprise.
 

wADVr

Adventurer
if I had a ‘12+ JK I’d play it simple and swap in a 5.7 Hemi using the AEV builders kit. simple, everything fits, reuse the auto tranny That is not a Chrysler tranny.

I am almost finished with my Ram 5.7 with 8 speed swap using the Jeep Speed Shop kit. I do hope it is everything I think it is. The Ram 5.7 puts out a little more usable power and the 8 speed tranny is highly regarded in efficiency and function coupled with its wide gear ratios. I looked into LS swaps and was not satisfied with the modules to integrate the GM drivetrain into the Jeep. That said I ended up with a few aftermarket modules to integrate the tranny as a stand alone unit and a module to run the cooling fan in a much better fashion. my basic requirement for this swap is to have it run like it should have to begin with. The 3.8/42rle auto was terrible and the 3.6/ wag580 or 6 speeds I drove weren’t much better IMO.
 

NatersXJ6

Explorer
This thread is evil because it has me recognizing each and every time I’m underpowered on the freeway. I’m intrigued by the RIPP Supercharger kits. Hopefully the $6k and seeming one-way nature of the installation will be enough to just push me over to the slow lane.
 

slvyj

Observer
I don't know why you want speed in a Wrangler, whenever I go over 65mph, I can literally see the gas gauge move. I have been passed on the German Autobahn by JKUs with the 2.8CRD doing easily 80-85mph.
 
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