Cummins R2.8 swap?

jcslax17

jcslax17

Member
The second 3.8 in my Jeep is starting to show signs of being on its way out. The engine is still under warranty but instead of just swapping in a new engine and having to eventually go through this process again down the road I was looking into other options. The option I’ve been leaning towards is swapping in the new r2.8 Cummins crate motor. Does anyone here have any experience with this motor? I’d be keeping the 6spd in the swap, if I was to do a Hemi swap I’d also want to keep a manual transmission as well.


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J

JKDream

Guest
jcslax17 said:
The second 3.8 in my Jeep is starting to show signs of being on its way out. The engine is still under warranty but instead of just swapping in a new engine and having to eventually go through this process again down the road I was looking into other options. The option I’ve been leaning towards is swapping in the new r2.8 Cummins crate motor. Does anyone here have any experience with this motor? I’d be keeping the 6spd in the swap, if I was to do a Hemi swap I’d also want to keep a manual transmission as well.


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It's not a viable swap. It makes similar power to the 3.8 - and significantly less than the 3.6.
Go with a V8 whether it be the Hemi - or an LS.
 
jcslax17

jcslax17

Member
JKDream said:
It's not a viable swap. It makes similar power to the 3.8 - and significantly less than the 3.6.
Go with a V8 whether it be the Hemi - or an LS.
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Im looking at the torque more so than the hp numbers, as well as the fuel economy. The latest factory tune from Cummins bumped the power up to 161hp and 310ft-lbs. there’s also other tunes out that that have boosted the torque to 450ft-lbs. would it be any more of a dog than my 3.8 on 37s even with 5.38s?


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Ddays

Ddays

Hooked
jcslax17 said:
The second 3.8 in my Jeep is starting to show signs of being on its way out. The engine is still under warranty but instead of just swapping in a new engine and having to eventually go through this process again down the road I was looking into other options. The option I’ve been leaning towards is swapping in the new r2.8 Cummins crate motor. Does anyone here have any experience with this motor? I’d be keeping the 6spd in the swap, if I was to do a Hemi swap I’d also want to keep a manual transmission as well.


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Click to expand...

This looks like one big ass migraine in waiting. I'd drive right on past that Cummins swap doing about 100mph on my way to the LS motor store.
Just think how awesome that beast would sound with a V8 in it. :brows:
 
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Snboarder113

Snboarder113

Hooked
There’s an episode of dirt every day where they put this up against a 4.0 and v8 all in similar tj’s. It’s a good watch, very informative. I would like to do it for the cool factor. But then they announced the price for the full kit motor once the r&d was done and not a chance. Thats motech money.


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Bierpower

Bierpower

Hooked
This is what I was looking into a few years ago. The biggest reason for going with the LS was that the diesel was not emissions compliant and the parts for it we're near impossible to find. While the mileage sounds super cool and the bottom end torque would be great, the engine availability and parts if anything ever broke I wouldn't want to be the one trying to work on it. LS parts are everywhere and way cheaper.

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Exodus 4x4

Exodus 4x4

New member
With the amount of work and money involved, you’re wasting all of it. There’s a reason we don’t touch the diesels.

By the way, you would get lost in the black cloud of smog that 450 ft/lbs of torque would create.


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jdofmemi

jdofmemi

Active Member
I would add that unless you are in mud or sand, it is rare that a lack of power what holds you back off road.

The 160 horsepower would make the trip to get off road a real drag though.

Ever wheeled with someone with a 4 cylinder? They will do ok off road, but headed up the mountain to get there, well, let's just say that part is no fun, and spent in the slow lane.
 
Exodus 4x4

Exodus 4x4

New member
jdofmemi said:
I would add that unless you are in mud or sand, it is rare that a lack of power what holds you back off road.

The 160 horsepower would make the trip to get off road a real drag though.

Ever wheeled with someone with a 4 cylinder? They will do ok off road, but headed up the mountain to get there, well, let's just say that part is no fun, and spent in the slow lane.
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Haha, no shit. Go drive the million dollar highway in Colorado with that and it won’t take long for you to start kicking yourself in the ass.


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Ddays

Ddays

Hooked
Exodus Jeeps said:
By the way, you would get lost in the black cloud of smog that 450 ft/lbs of torque would create.
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^^ This is a big deal if you're gonna wheel that thing a lot with buddies. You'll always be the guy that gets stuck last in line or you're gonna run out of buddies to wheel with. We were on a little run last year at the Bantam Jeep Festival here and got stuck following a piece of shit old CJ5 that hadn't been tuned up since 1982. I was getting sick from the fumes and unburnt gas spewing outta that old fucking junker. :icon_crazy: We stopped in the trail and let him get out of sight before we went ahead. I couldn't imagine following a belching diesel on the trail. No thanks.
 
jcslax17

jcslax17

Member
Ddays said:
This looks like one big ass migraine in waiting. I'd drive right on past that Cummins swap doing about 100mph on my way to the LS motor store.
Just think how awesome that beast would sound with a V8 in it. :brows:
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I do agree it’s hard to argue with the sound of a healthy V8. I was intrigued by the mpg and low end torque of the Cummins as well as being able to keep my transmission and not have to buy another trans as well as a motor, thought it would help keep cost down. That being said i know any swap is going to be a big investment


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jcslax17

jcslax17

Member
Ddays said:
^^ This is a big deal if you're gonna wheel that thing a lot with buddies. You'll always be the guy that gets stuck last in line or you're gonna run out of buddies to wheel with. We were on a little run last year at the Bantam Jeep Festival here and got stuck following a piece of shit old CJ5 that hadn't been tuned up since 1982. I was getting sick from the fumes and unburnt gas spewing outta that old fucking junker. :icon_crazy: We stopped in the trail and let him get out of sight before we went ahead. I couldn't imagine following a belching diesel on the trail. No thanks.
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That and the vibration is something I was worried about. But I figured if I didn’t have it tuned to the max it wouldn’t be a smoker.

I guess I’ll have to look harder into a v8 swap. I really would like to keep it a manual transmission and not make my mpg’s worse than they already are.


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jdofmemi

jdofmemi

Active Member
jcslax17 said:
......

I guess I’ll have to look harder into a v8 swap. I really would like to keep it a manual transmission and not make my mpg’s worse than they already are.


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You are showing your age with that thinking. The modern autos with lock up converters get very near the same mileage on the road, and off road they perform well.
Rock crawling is much easier, and you are able to be easier on the rest of the drivetrain than with a manual. In fact I have a hard time thinking of a place where the auto won't perform as well or better.

I always had manual transmissions, and swore I would never have an auto, but times change, the technology gets better, and I am at a point where easier is better.
 
13_gecko_rubi

13_gecko_rubi

Caught the Bug
jcslax17 said:
That and the vibration is something I was worried about. But I figured if I didn’t have it tuned to the max it wouldn’t be a smoker.

I guess I’ll have to look harder into a v8 swap. I really would like to keep it a manual transmission and not make my mpg’s worse than they already are.


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Just so you know a manual is actually worse on mpg than the modern auto. Look at the JL. The 8 speed is better on mpg than the manual.

If you are hell bent on the 2.8 (I'd also say go V8) look up/call axis industries in Indiana. They did the work on that off road power products conversion (ps it's running an fca 8 speed) and have done several 2.8 JKs. They are great to work with, I got my 8 speed controller from them.

All that aside having driven the 2.8 I would never do one. It doesn't feel powerful at all even in a TJ. Can't imagine in a JK. If you insist on a diesel, save yourself some money and buy a JL diesel when they get released. It will be a modern diesel with plenty of scoot. And I bet it would be cheaper. Otherwise I'm with everyone else, V8 all day!

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jcslax17

jcslax17

Member
jdofmemi said:
You are showing your age with that thinking. The modern autos with lock up converters get very near the same mileage on the road, and off road they perform well.
Rock crawling is much easier, and you are able to be easier on the rest of the drivetrain than with a manual. In fact I have a hard time thinking of a place where the auto won't perform as well or better.

I always had manual transmissions, and swore I would never have an auto, but times change, the technology gets better, and I am at a point where easier is better.
Click to expand...

Im only 25 haha. I know that the autos are just as good if not better but I enjoy driving a manual and enjoy being different from all the other built jks out there.


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jeep_pride

jeep_pride

New member
The R2.8 seems great off the specs - still would agree with some here that an LS or Hemi would be best. More power and likely easier swap as both options have kits available for the jk.


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jdofmemi

jdofmemi

Active Member
jcslax17 said:
Im only 25 haha. I know that the autos are just as good if not better but I enjoy driving a manual and enjoy being different from all the other built jks out there.


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I'm glad to see some of the younger guys willing to do the work to wheel a manual.
Most your age won't even drive one. I'm sure you already know that.

I was like that until just a few years ago, but now I have given in and took the easy way with an automatic

Good luck with whatever you choose.
 
BaddestCross

BaddestCross

Active Member
jdofmemi said:
I'm glad to see some of the younger guys willing to do the work to wheel a manual.
Most your age won't even drive one. I'm sure you already know that.

I was like that until just a few years ago, but now I have given in and took the easy way with an automatic

Good luck with whatever you choose.
Click to expand...
Same here. I put in my time on the stick... Earned the right to be lazy and enjoy my automatic. 🤣

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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
 
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