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Discussion Starter #1
I am planning to start a Jeep Wrangler swap soon. I havent picked up the donor Jeep yet but I have a couple of options. I can use either a YJ or TJ.

I am looking for any advice as to whether using coils or leafs might result in the best ride considering the additional weight of the new engine.

Any comments you may have would be very helpful when I make my final choice. Thanks!
 

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I am planning to start a Jeep Wrangler swap soon. I havent picked up the donor Jeep yet but I have a couple of options. I can use either a YJ or TJ.

I am looking for any advice as to whether using coils or leafs might result in the best ride considering the additional weight of the new engine.

Any comments you may have would be very helpful when I make my final choice. Thanks!
Coils are always going to ride better than leaves.
 

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Leafs are easier to set up, and easier to adjust (add a leaf different springs etc.) due to changes in geometry from the added weight and possible needed lift...

But coils due ride better, but in the jeep factory set up they are more sensitive to changes. You have more of a chance of getting bump steer, death wobble, and wondering when you lift the thing and add weight... JMHO...
 

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My comment is....you need to ask a jeep forum, not a Cummins forum
That's Nice !!!!! That's like telling to to leave because you have a ford!!


Welcome !
In the build section , there a few guys with jeeps that have Cummins ,ask them .

Both spring work well and also depends on what you have plan for the Jeep.
 

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It comes down to what is available and how much money you want to spend. The coil suspension on a TJ is much better both on the road and off. On the other hand there are a lot of good leaf spring lifts out there or you could do a coil conversion. My opinnion: If you have the extra cash or the TJ is not much more than the YJ, buy the TJ. It will pay off in the long run. You can usually find high milage 4 cylinder TJ around here for 3K or less.

I am building a cummins powered CJ8 right now. I built a custom 4 link in the rear with 5.5" Rubicon Express springs in the rear. In the front I am spring over with 1.5" RE springs. When I have some more money, I will be going coil over in the front.

If you have any other Jeep questions, just let me know!

Bill
 

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That's Nice !!!!! That's like telling you to leave because you have a ford!!
I wasn't being rude, just simply stating a fact.
 

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I would say go for coils. The initial cost will be more but you can swap out the coils cheaply to get the ride/height yo want. A "good" pair of custom leaves will set you back $800.... then what happens when you want to change? I am currently putting a coil setup on my 75' Scout II so this is something I've thought alot about. -wingnut13
 

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Welcome to the site BongCAT, sorry for the rude comment LincTex made. He does not reflect the opinion of me or others here.
To answer your question
There are a few pros and cons for both suspensions. The leafs will simplify the setup since there are fewer parts needed. There is some space concerns with link brackets on a TJ. The Coils are much more adjustable and IMO easier to adjust from a spring r/r standpoint. Coils are over all lighter weight. Coil overs is another option as are 1/4 elliptical leafs. But now we are getting into some high dollar stuff. Leaf lifts are pretty cheap to get used, but that depends on your area. I don't think you can go wrong with either YJ or TJ, I do think a CJ is getting pretty old in the tooth and technology has not kept up with them as well as the newer stuff. There are several Jeep guys here that will help out and can relate to the chassis and weight issues you will need to address.
 

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I'm not to familiar with jeeps, but i thought the TJ came stock with coils. Maybe get a hold of a Jeep that already has coils.
 

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That was NOT factual it was your opinion.
Fact: This is a Cummins engine forum
Fact: The question was about Jeep suspensions
Fact: This isn't a Jeep forum
Fact: Not everyone here owns a Jeep
Fact: Perhaps better/more answers could be had by asking other jeep owners

I WAS being factual.

FACT: Just because my answer was brief doesn't mean it was rude. That is just the way you are taking it :)
 

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Fact: This is a Cummins engine forum
Fact: The question was about Jeep suspensions
Fact: This isn't a Jeep forum
Fact: Not everyone here owns a Jeep
Fact: Perhaps better/more answers could be had by asking other jeep owners

I WAS being factual.

FACT: Just because my answer was brief doesn't mean it was rude. That is just the way you are taking it :)
I'm going to have to agree here as well. That was a very, very vague question that has probably been argued up and down many many times, on many many forums in the neverending battle of coils vs leafs :)

Everyone has their own preference. IMO - Coils are for rockcrawlers & a cushy ride, leaves are for mudders and more of a solid/stiff ride. Shocks also play a large part in ride quality regardless of the spring setup.:eek:
 

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Discussion Starter #14
Thanks

Thanks for all of the good information. This helps me make my decision for my up coming build. I also posted a similar question on Jeep forums and got similar responses. This will be more of a daily driver backroad truck so seems like coils is the way to go.

Also the reason I posted here was that I assumed members on this forum would be more knowledgeable about the changes that occur when a heavier engine is installed in a vehicle. And also because there are more Cummins/Jeep owners here than any jeep forum.

Again thanks for the advice.
 

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DarylB I respect your position on this, and I am not trying to argue with you but the question didn't seem vague to me. He asked for advise about Jeep suspensions as they related to, or were effected by the added weight of the swapped in engine. Now I assume the engine to be a 4bt, since this would not be the forum to ask about big block Chevy swaps. He did not ask a simple generic question about coil v/s leafs, if that were the case I would agree a Jeep forum would be better. That was why he was asking here after all a few of us have done the exact swap he is considering. It's the 4bt engine in the Jeep that makes the difference. When I have talked to Jeep enthusiasts either on line or in person about my 4bt TJ they have no idea the weight, etc. that is involved in doing such a swap.
 

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Discussion Starter #16
Ggg;14593 That was why he was asking here after all a few of us have done the exact swap he is considering. It's the 4bt engine in the Jeep that makes the difference. When I have talked to Jeep enthusiasts either on line or in person about my 4bt TJ they have no idea the weight said:
 

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I would use a YJ, because of the reasons stated above. Its much easier to adjust leaf springs to a heavier weight than coils. I have a Cherokee XJ and I would never consider putting a 4bt in it, only because of what happened when I added a good front bumper and 12k winch. I lost 2" in height in the front, so I need stronger springs to compensate. A 4bt will add more weight than my bumper and winch.

I do have to say that the ride of a TJ is a bit better (I have owned both), but not enough to get excited about.

Jim
 
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