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Discussion Starter #1
Okay so I'm new to the forum so I haven't explored every nook and cranny yet... But I would like to know if anyone has done a 4bt engine swap that didn't cost 20k, love the sound of a diesel but I don't like the 20k cost to get my cluster to operate and make the computer happy, also considering bypassing computer and all, just making a new cluster 4bt friendly but I've never tackled anything like this, many thanks!!
 

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It's not required but introducing yourself
and your rig on our Welcome Page thread
is sage etiquette, fwiw.
It's good to be acquainted to people when
asking them for help.

It's also cool to include what
references and/or Google searches
yielded no results for you so possible responders
know you've exhausted all data sources for
already documented modifications ...

I'm not policing ; just trying to get ya pointed
in right direction :wink_animate:




 

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Is this for off road only or do you plan to run down the highway? Emissions in your area? Pretty much anything electrical will run thru the ECU so if you want to ditch the computer everything you want will need to be rewired. I would just pull the dash and do aluminum with the gauges you want.
 

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you can go piss up a rope
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OP's quest is hopeless and sounds like the typical "all hat and no cattle" medium-duty diesel pickup truck owner that whines that diesel costs $4/gal.

Welcome to JKO.
 

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I have never done it, but I looked into it for a bit. The easiest way would be to scrap every wire, every computer that Chrysler put in the Jeep, right down the the turn signals, windshield wipers and even the heat and A/C. Then start from scratch with analog gauges, and a custom dash. This is because the PCM and the TIPM control everything that your JK does, and they quite often need to talk to each other. The fact that this is a 100% mechanical engine is your problem. The JK relies on electronic everything to know what is happening, and you can’t get that with a mechanical engine.

If you are dead set on a diesel the Cummins R2.8 would likely play nicer with the JK, but will be way more money as it is a new crate engine, plus it is electronically controlled.

In my opinion an LS 6.2L truck motor will have more torque at and just off idle than a diesel as the LS torque curve is fairly flat but peaks later, and a diesel is steeper, but peaked early. Plus the diesel doesn’t have much power untill the turbo spools up where as an N/A LS will have power as soon as you hit the throttle. Plus there are several venders on here that specialize in LS swaps like Motec and RPM Extreme and can make everything work like normal.

We haven’t even begun to scratch the surface on being emissions legal. You will need to be legal for the year of the engine or vehicle (whichever is newer) is now I believe it works in most jurisdictions. With a 4BT that will be your JK. This means you will need an EVAP system, which is computer controlled. That is just the start of the hassle for emissions.

If this Jeep isn’t going to be licenced for the road, you have less to worry about and can just giv ‘er shit and rip all the Chrysler bullshit out and not look back, while having a cool JK buggy. If that is the case start a build thread here as we will want to see the progress.
 

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I know a guy that did a 4bt swap in a Jeep TJ. It never performed even as good as the stock 4.0. It was fun and unique, but ultimately he LS swapped it.

My opinion, based on that experience, is to skip the 4BT. If you’re set on diesel move up to a 6BT or go to LS.
 

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Conquistador brings up another good point about the 4BT in that it is a dog. They came with 105hp for pre ‘98 and 170hp after ‘98 with 268 and 420 ft/lbs respectively.

Another con to them is the weight of them. They can weigh 750-800lbs wet and a 6bt is about 1100lbs, where as an iron block V8 5.3L LS is about 500 lbs.

At the end of the day it is your Jeep and you are free to build it the way you want to.
 

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Discussion Starter #10
Awesome all of you guys, I'd like it to be on-road, as far as emmisions I don't have the yearly checkup in the county I live in but I didn't know if anyone had a kit or a way they did under 20k, for the 6bt wouldn't I have to have a beefier frame? And I hate electronics, old-school like that 😎 for ls swap I have access to an '01 Silverado 4x4 with a 5.3 and a 2wd '05 6.0 from a Silverado, I'm not too keen on this 3.8 with the 4 speed eclipse tranny lol, definitely want a manual or a beefy auto, also for the 6bt is there room? And I thought the 4bts could be tuned way up, something else I thought of was leave Chrysler computer, and run a solenoid to the keyswitch power the diesel system so I have the creature comforts but mechanical engine in case of alternator failure, all for reliability and I haven't heard as much good from the r2.8 as I have the 4bt, but all input is welcome!
 

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If your goal is to have power under 20 grand, that’s very doable if you’re capable of doing the work. I’ll have less than 20k wrapped up in my L86/8L90/atlas swap. Now if you add in axles, tires, suspension- it gets pretty crazy very quick.
 

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Discussion Starter #12
If your goal is to have power under 20 grand, that’s very doable if you’re capable of doing the work. I’ll have less than 20k wrapped up in my L86/8L90/atlas swap. Now if you add in axles, tires, suspension- it gets pretty crazy very quick.
that was going to be my next question, just for driveability will the stock Dana 44/30 combo hold up to the 4bt or ls swaps? And I'm going to do this one for driveability but I'm going to do a beast one for toying, probably just take a short 1ton truck and put a lift and jk tub on it but no idea how it'll line up, or put a 4bt or 6bt or 6.6 something that'll pull a house down on 44x16s into a good ol to with a beefy frame and axles
 

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Discussion Starter #13
If your goal is to have power under 20 grand, that’s very doable if you’re capable of doing the work. I’ll have less than 20k wrapped up in my L86/8L90/atlas swap. Now if you add in axles, tires, suspension- it gets pretty crazy very quick.
also I'm definitely capable, I just don't have the know how, and of course, 5+ heads are better than one, alot of you guys have done it or something similar or scour the internet for answers to make things run beautifully, so much respect
 

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Discussion Starter #14
OP's quest is hopeless and sounds like the typical "all hat and no cattle" medium-duty diesel pickup truck owner that whines that diesel costs $4/gal.

Welcome to JKO.
I thank your welcome, where I live it's about $3 a gallon but I love mechanical things, much more reliable than 529,484 different sensors that could maybe possibly be due to something obscure
 

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If I was doing it on a budget, I would look for a LS 5.3/6l80, do the Motech Kit keep the original transfer case and axles and enjoy.

But as with most things, one thing leads to another, yada yada yada, atlas, coilovers, bypass, 60’s and 40’s. Then you’ll need a cage. Then you’re going to want seats, then...
 

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Discussion Starter #16
It's not required but introducing yourself
and your rig on our Welcome Page thread
is sage etiquette, fwiw.
It's good to be acquainted to people when
asking them for help.

It's also cool to include what
references and/or Google searches
yielded no results for you so possible responders
know you've exhausted all data sources for
already documented modifications ...

I'm not policing ; just trying to get ya pointed
in right direction <a href="http://www.jkowners.com/forum/images/smilies/wink_animate.gif" border="0" alt="" title="Wink Animate" >:)</a>
Absolutely, I'll get a good picture up on there tomorrow, love the community feel already, I honestly didn't expect this quick of a response let alone as many as I have, absolutely love it
 

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Discussion Starter #17
If I was doing it on a budget, I would look for a LS 5.3/6l80, do the Motech Kit keep the original transfer case and axles and enjoy.

But as with most things, one thing leads to another, yada yada yada, atlas, coilovers, bypass, 60’s and 40’s. Then you’ll need a cage. Then you’re going to want seats, then...
Hahaha, well of course, always moving foward
 

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If I was doing it on a budget, I would look for a LS 5.3/6l80, do the Motech Kit keep the original transfer case and axles and enjoy.

But as with most things, one thing leads to another, yada yada yada, atlas, coilovers, bypass, 60’s and 40’s. Then you’ll need a cage. Then you’re going to want seats, then...
Yep, that’s what happened to me. Started with the least expensive LS I could find (used 5.3) and ended up going 6.2 L94, 6L80, new transfer case, Camaro SS fan, D60’s, 1350’s, 40’s, beadlocks (because I needed new wheels). It’s never ending.
 

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I’m sure you are familiar with Rattletrap, the 6bt JK built by MBRP. That one used the JK frame. Here is the build thread on pirate https://www.pirate4x4.com/forum/jeep-hardcore-tech/946856-mbrp-diesel-jeep-4-door-jk-truck.html.

Peterson’s offroad magazine put a JK tub on a ram frame for their ultimate adventure when I was in high school. That was in 07-08ish. You might be able to check their archives for those articles.

As far as an LS, a gen 4 (07-13) with a 6 speed tranny will be your best bet. More power and the 6 speed is 10 times better than the 4L60.

Personally my dream engine is the new gen 5 6.2L truck motor the L86 since the torque curve is nearly flat and around 400 ft/lbs. It is also a direct injection engine. The speed transmission that goes with it is also pretty awesome from what I heard. So basically what Conquistador is doing right now.
 
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