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4.5 Duramax Diesel Cherokee Retrofit??

KJurasek

NAXJA Forum User
Location
Lafayette, LA
Just for the fun of entertaining an interesting idea, does anyone have any thoughts on the prospect of the GM 4.5 Duramax as a viable retrofit in place of an LS1 in a Cherokee?

I have considered swapping in a 4 BT (too noisy and dirty), then a 3.0 CRD (too few and too expensive) but scrapped the idea.

Now I hear something about GM (or rather Duramax) reviving the 4.5 Duramax. The engine is designed to take up the same amount of room as a LS series engine so it should be able to fit in a Cherokee. The HP output and torque is similar to the 3.0 CRD, but the question is would it cost less to buy and install?

Some interesting questions for thought.


Let me know your thoughts on this
 
The 4.5 was supposed to start production fall of 2009....'talk' of reviving the 4.5 started over 1.5 years ago.....and nothing yet.
 
Hmm.. size of an LS/LQ motor. How about, using an LS/LQ motor. LQ4 FTW!
 
I am looking at a LQ4 6.0 with the 4L60E transmission. I am still going to put in the 4.9 Stroker and see how I like it. I will keep the 4.9 while I build the LQ4. Once the LQ4 is completed, then I will sell the 4.9 (to recoupe some of my costs).

But the thought of a 4.5 Duramax is intriguing.
 
Just a note to those considering a Diesel swap... The gears in your axles are going to be way to short.

T4BT makes it's 105hp at 2,300rpm and the 265ft-lbs of torque at 1,600rpm. The 4.0 makes 190hp at 4,600rpm and 231ft-lbs at 3,000rpm.

Do the math and it makes 3.55:1s and 35s look appealing...
 
T4BT makes it's 105hp at 2,300rpm and the 265ft-lbs of torque at 1,600rpm

Thats interesting. I'd like to see how the rest of it before 1600rpm plays out. This is just from what I have read on Ifsja.org, where they do lots of 4bt swaps, they seem to find that peak torque is the sweet spot for best mpg. Some were finding 1800-1900 rpms to be it, which I'm assuming they were running different turbos. Either way, before that was apparently below the boost curve, getting over 30% less mpg. Pretty substantial.
 
Just a note to those considering a Diesel swap... The gears in your axles are going to be way to short.

T4BT makes it's 105hp at 2,300rpm and the 265ft-lbs of torque at 1,600rpm. The 4.0 makes 190hp at 4,600rpm and 231ft-lbs at 3,000rpm.

Do the math and it makes 3.55:1s and 35s look appealing...


and weighs around 8-900 lbs fully dressed, I love the b series but i'd never put one in a unibody Jeep.
 
This was about the Duramax 4.5, not the 4 BT. I have seen the 4BT in action and I would not consider it a good "road worthy" swap. There are other diesels out there that would be a beautiful retrofit.

3.0 CRD anyone??

I just heard words about Jeep buying the 4.5 Duramax and installing it in one of their vehicles.

A possible solution to the power problems with the JK??

Maybe.
 
How would Jeep buy the Duramax when Duramax is GM, Jeep is Chrysler, and Chrysler already has a diesel that fits a Jeep? A couple actually. And no way would the new 4.5 Duramax (which isn't even in production, nor apparently likely to be seen in America) be cheaper than the existing 3.0CRD, that one, already exists and is real, and two, could be found used?

Before you decide that the 4.9 just isn't enough and you have to swap it out, how about you install it and see how it works? It's not like it takes big beastly motors to move these little things. Realize that your chances of finding a decent diesel at a reasonable price, that would package properly in the Jeep, are pretty slim to non-existent. At least, your chances of finding one that would be an improvement over a 4.9 stroker, powerwise, are non-existent. You could always run a 2.2 Nissan like EcoMike, or a VW 1.9 or 2.5TDI, but you're not likely to see any power out of either of those.

Your earlier thread about swapping the Cummins 6.7 made more sense, even if the idea was impossible. At least that engine is real.;)
 
These are just possibilities Darky. I am just hearing rumors about Jeep buying the rights to 4.5 Duramax. Yes, you are correct about the 2.8 and the 3.0 CRD and why would Jeep need the Duramax. But then again, they do strange things up there in Michigan. They have been talking about the Brute for years and we still have yet to see it come to market. A real interesting concept would be the Brute with a 3.0 CRD or 4.5 Duramax.

These are just things I hear in the wind. Not sure how true they are, but some interesting possibilities.

As for my 4.9, well the downfall is not the engine, but the transmission behind it (AW4 anyone?). I would rather pull the whole f-en mess and just go with something that is just much better, more reliable, more horsepower, and better gas mileage--LQ4 6.0 with the 4L60E. Not to mention all the inexpensive aftermarket parts for the LS series engines.

I feel like I am trying to reinvent the wheel sometimes.
 
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What is making me think about replacing it? Better MPG and horsepower. Plus the sound of a V-8. I think the V-8 will long outlast the 4.9 with less headaches.

I am not fully decided on replacing the stroker yet. I will have to see how I like it. I am putting a good bit of beef on the XJ and wonder if it will outweigh the benefits of the 4.9. I have added full 3/16" bumpers front (with a winch) and back, a 6" + lift with Treks long arm conversion, a HP Dana 44 front, and Dana 60 (35 spline) rear, and frame stiffeners. I know it sounds like a lot, but it is what I decided to go with.

I want to see how far I can push the XJ. With everything above, I think the LQ4 6.0 will be a good match up. I will have to see how the 4.9 handles the load, but with all the added weight I am not sure.
 
Your XJ isn't anything beyond the norm of a well-built XJ. While a V8 is frickin sweet, it's a big hassle that takes way more time and money than you might think. A lot of guys are running the same build as you, but with 1/4" bumpers and a cage, with a stock 4.0. Hell, look at Jeepspeed racers: they push their rigs and engines hard, running super deep gears, in a race environment, with great success. One of them (the name slips my mind, but I think it's the Filarski Brothers...they'll have to chime in and correct me) is pushing 300hp out of their 4.0, no turbo. Definitely wait until you get the stroker in before you make plans to replace it. Goatman runs a 4.7 stroker in his KOH buggy.

For the AW4, you won't hear many complaints about it from people here. Heck, it's the same basic trans run behind twin turbo Supras; it can handle some power. :D

As far as power and mpg, a stroker might not equal a V8 in torque output, but the V8 isn't necessarily going to improve on mpgs, at least not with a 4 speed. Frank Z and John D are both running LS series V8s, and mpg hasn't come up as a bonus. You can probably hit around 17mpg out of your stroker. There are a couple guys running 35s-37s on a stroker and achieving that mileage.
 
Whats wrong with the aw4? If you really want that "sound of a v8" sure do the swap but if you don't want the jeep to sit while you work out the problems of a v8 swap, you can build the 4.9 and bolt it in whenever. A 4.9 should haul balls either way and make the power of a stock 6.0. Plus get better gas mileage. Both trannies have locking torque converters so i cant see one be much more efficient.
 
Frank Z and John D are both running LS series V8s, and mpg hasn't come up as a bonus.

i think i remember both of them saying that if MPG is a reason to justify a V8 swap, you are mistaken. HP =/= MPG.




HP per dollar, most will claim the V8 is a far better value.

as for reliability, i like the idea of a fairly stock motor with easy to find parts over something completely worked. ive seen many smooth running strokers on the net, but ive also seen very few last as long as a stock, plain old, 4.0.
 
i think i remember both of them saying that if MPG is a reason to justify a V8 swap, you are mistaken. HP =/= MPG.




HP per dollar, most will claim the V8 is a far better value.

as for reliability, i like the idea of a fairly stock motor with easy to find parts over something completely worked. ive seen many smooth running strokers on the net, but ive also seen very few last as long as a stock, plain old, 4.0.

From what I understand, the LQ4 (6.0) with the 4L60E behind it is a much more efficient engine than the 4.0 (or 4.9 for that matter). To be honest, I have no real complaints against the 4.0 (aside for relatively poor MPG and weak after market support), but after all the work and expense I put into the 4.9 I realized I might have been better off taking a different route.

Considering as common as the LQ4 is within the GM truck/SUV market, and reading some peoples retro-fits into the XJ, I began to question the 4.9. Why am I putting all this work and expense into the 4.9 when I could go with a LS swap? Consider all the benefits of the LS engine---more reliable (in stock form), better aftermarket support, more power, better MPG?

In short, it takes a lot to modify the 4.0 to even closely match the LQ4 (6.0) in stock form. Not to mention the engine would be stock and with a warranty.

It just has me thinking.

hasta
 
From what I understand, the LQ4 (6.0) with the 4L60E behind it is a much more efficient engine than the 4.0 (or 4.9 for that matter). To be honest, I have no real complaints against the 4.0 (aside for relatively poor MPG and weak after market support), but after all the work and expense I put into the 4.9 I realized I might have been better off taking a different route.

Considering as common as the LQ4 is within the GM truck/SUV market, and reading some peoples retro-fits into the XJ, I began to question the 4.9. Why am I putting all this work and expense into the 4.9 when I could go with a LS swap? Consider all the benefits of the LS engine---more reliable (in stock form), better aftermarket support, more power, better MPG?

In short, it takes a lot to modify the 4.0 to even closely match the LQ4 (6.0) in stock form. Not to mention the engine would be stock and with a warranty.

It just has me thinking.

hasta
Warranty might not apply when installed into an XJ, unless you buy it as a crate engine, and then you're looking at ridiculous money. And again, the people who've done the swap, with 5.3s, no less, are reporting mileage no better, and in some cases worse, than the 4.0. I know of at least a couple with strokers getting around 17 mpg.

Have you read John D's build thread, or Frank Z's? If not, you really should. Both would recommend the swap, but make sure you are going in with reasonable expectations.
 
i think i remember both of them saying that if MPG is a reason to justify a V8 swap, you are mistaken. HP =/= MPG.

Unless you have the diesel, I get 188hp with 335ftlb, AND get 30+mpg on winter fuel.

I just need someone to t-bone the passenger side of my CRD Liberty so I can swap the drive train into my XJ :(
 
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