Anyone seriously considering the R2.8? (Cummins)

[Clint Rivera]

The 4l60E's 1st gear was low enough for me to run 37's on 3.73 geared axles and use overdrive no problem. I had a hybrid chevy / Jeep NP231 that I mated up to it. It was a pretty cheap swap, not much more than having two axles regeared.

 

[FireJeep]

I am still toying with this idea, I am not really interested in spending 20 or 30 k, to me that is illogical. For example, I don't want after market gauges, the stock ones are fine for me, I would really like the whole thing to appear stock and un modified, until you open the hood of course. But even then, I don't want billet this or chrome that, just a stock appearance. So, to those that have actually done this swap, is $12k an accurate prediction? Just for the parts, I realize this would not include labor, I would be doing all the labor myself. From what I have read other than welding in the motor mounts and figuring out how to space the radiator back to allow for the intercooler and to keep the fan in a shroud everything else is, more or less, bolt on, no?

 

[BugoutJeep]

$12k is possible, but unlikely. With adapters, hoses, clutch, motor mounts to block and frame, intercooler, intercooler piping, some wiring, generally you're going to refresh stuff while it's apart, you'll likely want an electric fan, exhaust, etc.

I definitely spent more than I needed but I'm basically in the low $20k's with my labor only. The radiator/intercooler/fan setup was what really drove up my price for the kit from Axis and I'm not sure if it's necessary, but I didn't want to get bogged down for a long time trying to figure everything out or buying stuff multiple times and having to get a few tows home while I figure stuff out. I added an extended range Genright tank as well, which wasn't cheap, did a bunch of maintenance while I had easy access, and added Dakota Digital gauges. I haven't really sat down and totaled everything up, but it's high.

I didn't necessarily want aftermarket gauges either, but the PCM just kept being in the way. Axis Industries is talking about offering a module to keep the gauges, but you'll have to talk with them to find out how to get it.

The logic to a swap like this is preference. If you go to a car lot and $40k vehicles get you very excited and the leather and automatic everything with a beautiful ride is what you really like, well that's easy. The only vehicle that really interested me new was the Colorado ZR2 with the Duramax. The problem is that where I spend most of my time, the body will get destroyed, parts are probably expensive and it has a bunch of stuff I don't really care about. I'm not a fan of the gearing, it won't fit the trails we have around the local farms. Also I'd ditch the bed and go flat bed, so I'd been probably have been close to $50k and not really have the style I like. And if you include the taxes and insurance, in 10 years you're talking about $70k in the vehicle without any maintenance or fuel.

 

[RustyAutoholicGuy]

So just to throw another idea out there you could do a Kubota Diesel swap which is MUCH cheaper with a massive increase in both torque and mpg. Here is my break down for my build right that I'm doing:

Kubota Diesel 4.0L adapter - $675
Kubota Diesel Engine - $700 ~ $1500
Borg Warner K03 Turbo New - $450
Drive pulley system - $800ish
AW4 Transmission with 90K on it -$75
Total: $3500

First things first the price is subjective on the deals you can find and how much trading and wheeling/dealing you can do. I got a great running AW4 with 90Ks on it for $75 bucks, and if I had used the V1903 I bought my conversion cost would be close to $2700 total but I wanted the V2403 for my rig for the extra hp and torque since I was going to run an automatic transmission. If you have a manual you could run the V1903 with no issues at all.

So the 03 series of Kubota engines can be gotten for under 2K easily, it's a mechanical diesel with no computer that are small and relatively light and quiet, especially compares to a 4BT or Mercedes Diesel.

I originally was going to put my Kubota V1903 into my Wrangler which I bought running off of craigslist for $700. The V1903 is the smallest in the engine family. Here is the list of engines as I know them from Kubota for the 03 Series:

V1903 - 4 cylinder 1.9L
V2003 - 4 cylinder 2.0L
V2203 - 4 cylinder 2.2L
V2403 - 4 cylinder 2.4L
F2503 - 5 cylinder 2.5L
F2803 - 5 cylinder 2.8L

The V2203 is the most common that came out of reefer unit. The V stands for 4 cylinder and the F stands for 5 cylinder. The next two numbers are the displacement and the the last two numbers are the engine series.

I found a steal for a V2403 which with shipping I paid $1500 for, so I could have cut my engine cost in half by staying with the V1903 but I'm going to be using that for another build so I'm not worried about it! There is also a Direct Injection and Indirect Injection on all these motors, I've got the Indirect Injection for both so my power will be down a little.

However with that being said, with the 25ish PSI boost from my turbo going through the intercooler, I'm looking at around 135hp/300ft-lb from my V2403. Also realizing I will have the 300ft-lb of torque from about 1600 rpm through redline.

For fuel economy I'm looking to get somewhere in the mid 30s for MPG. With fine tuning the fuel pump and the turbo using the boost and EGT gauges, I'm hoping to highway around 35+ miles per gallon. I currently have 3.73 gears which are decent for my diesel, but I might be looking at doing a lift or a rear gear in the future to help improve that number.

With that being said, I get around 14 ~ 17 in my Wrangler right now between city and highway so if I could get between 28 ~ 34 with the diesel swap, it will pay for itself very quickly in terms of money saved at the pump.

The only other major factor you need to consider with the Kubota engines are they are low RPM, I believe they are factory governed to 2800rpm, but I've read and I have been told you can up the limiter so it will hit 3000 ~ 3200.

I know my 2006 Liberty CRD will do 4000 rpm, but I really hate pushing the engine past 3000 rpm, just doesn't ever seem to need it, it's better to let her shift and torque through the next gear.

Hope this helps!
-Grant

 

[BugoutJeep]

That's awesome. I really like that setup for sure. I'm going to have to look at your posts.

I haven't seen that many of those in my area, but I want to do some more swaps in the future. I'm not sure in my area if there's any diesel you could get under $2k that isn't a VW TDI weighed down by a Jetta. Typically the issues I saw around here was that you'd find an engine for $3500+ and then you'd need to find a specific transmission and transfer case that everyone wants and there's several codes that some say work and others say don't and different spline lengths and counts, new driveshafts, axles, suspension, tub work, linkage work, etc. And if you rebuilt the engine you'd have another $2-4k if you take it to a shop and then you're custom fabricating stuff for months to years depending on your time constraints.

Now that I have a diesel Jeep, I may likely pursue something like this, but downtime was very critical for this swap, hence a brand new engine that needed nothing and a conversion kit. It didn't work as smoothly as I planned, but it's doable by yourself with minimal skills. It would have likely taken me 1 or 2 years to gather the parts for this swap and then for me it would have been a year to install everything, design and fabricate some brackets that I didn't really know where they'd go until more stuff was in place. So just something to think about when you're contemplating a swap, if it's in a vehicle you really like to drive.

Oh for MPG on the 2.8 Cummins, it will certainly approach those high 20s mpg, but you're going to really have to look at an EGR delete (more $/time), I would think to get solidly in the 30s. Diesels can pretty much all be geared and driven in a way to get crazy high mpgs. My Dodge 2500, if you'll watch the RPMs and speed and keep it unloaded will get mpgs to make crossovers blush.

 

[RustyAutoholicGuy]

That's awesome. I really like that setup for sure. I'm going to have to look at your posts.

I haven't seen that many of those in my area, but I want to do some more swaps in the future. I'm not sure in my area if there's any diesel you could get under $2k that isn't a VW TDI weighed down by a Jetta. Typically the issues I saw around here was that you'd find an engine for $3500+ and then you'd need to find a specific transmission and transfer case that everyone wants and there's several codes that some say work and others say don't and different spline lengths and counts, new driveshafts, axles, suspension, tub work, linkage work, etc. And if you rebuilt the engine you'd have another $2-4k if you take it to a shop and then you're custom fabricating stuff for months to years depending on your time constraints.

Yeah I had really considered the VW TDI swap, I even got a TDI Golf that I thought I might do it with before I ran into major engine failure. The other problem I ran into with the VW TDI though was the Adapters were expensive and the one pulley system I did find was like 5K, and then you had to buy the VW ECU to Jeep ECU adapter to make everything talk, and it all got really complicated and expensive very quickly.

I really looked hard at the Mercedes OM617 swap but after owning a OM617 Swapped Comanche that never ran right I wanted to stay away from the older diesel stuff.

Truthfully I happened upon the Kubota stuff because of my 1947 CJ-2A project and after doing some research on it I found Kubota Swappers and that changed all my projects and plans I had for everything!

My goal is to have my Wrangler back on the road sometime next March hopefully for my birthday!

Thanks
Grant

 

[BugoutJeep]

That's awesome. Good luck with it. I really like the idea of a mechanical diesel, but I have found the common rails to be so easy to live with on a daily basis. However that's probably just due to time. We do have a tractor that's 40+ years old and that engine is incredible, but it's roughly the size of a 6BT, so not really a great Jeep option.

In a few years, I may look at importing some Jeep or Hilux with a mechanical diesel and then trying to restore it. I think 25 years and we can import vehicles built the way they were supposed to be built. In the late 90s I think there's some better mechanical diesel options and early to mid 2000s there's a lot of common rails that are still robust. Just something else to consider.

When I was overseas for work a lot a few years ago, everything looked like the styling from the 90s, but built for hard use and cars and mini-vans were like 40-50 mpg and trucks were all high 20s to 30s and half the cost or more of the options we have brand new. And diesel was cheaper than gas, which was mostly for mopeds. I'm not sure if I saw any vehicle over 4 cylinders, even in their heavy trucks. And the guys I was working with had no idea how to drive an automatic. It's just kinda funny what we spend our money on here. I may add that besides the vehicle selection and occasionally scenery/adventure, the US is so amazing by far.

 

[Chris]

$12k is possible, but unlikely.

This is what I keep trying to tell people.

They keep telling me, "Well you can get a Cummins R2.8" swap for 9k".

I tell them yeah, you can, but that's far from a "complete" swap, and you're going to end up spending around 15k or more to put it in there and do it right, especially if you're paying a shop.

Costs add up quick, that's for sure.

 

[BugoutJeep]

Yep. The key words are right and swap. Conversion may convey what you're trying to accomplish. I do think for Apples to Apples R2.8 vs brand new crate motors, it's a great swap and the extra up front cost will be made up by fuel and trying to leave some stock components intact, but it isn't going to be $9k.

If you're a builder with lots of stuff and parts around and time to search junkyards, you could do it pretty cheap after you have the engine, but that's not most people that are looking to do this conversion.

 

[RustyAutoholicGuy]

That's awesome. Good luck with it. I really like the idea of a mechanical diesel, but I have found the common rails to be so easy to live with on a daily basis. However that's probably just due to time. We do have a tractor that's 40+ years old and that engine is incredible, but it's roughly the size of a 6BT, so not really a great Jeep option.

In a few years, I may look at importing some Jeep or Hilux with a mechanical diesel and then trying to restore it. I think 25 years and we can import vehicles built the way they were supposed to be built. In the late 90s I think there's some better mechanical diesel options and early to mid 2000s there's a lot of common rails that are still robust. Just something else to consider.

When I was overseas for work a lot a few years ago, everything looked like the styling from the 90s, but built for hard use and cars and mini-vans were like 40-50 mpg and trucks were all high 20s to 30s and half the cost or more of the options we have brand new. And diesel was cheaper than gas, which was mostly for mopeds. I'm not sure if I saw any vehicle over 4 cylinders, even in their heavy trucks. And the guys I was working with had no idea how to drive an automatic. It's just kinda funny what we spend our money on here. I may add that besides the vehicle selection and occasionally scenery/adventure, the US is so amazing by far.

Thank you! Also I agree with you about the import as well!!! There were several Wrangler models sold overseas not in the states that I would love to owner. Particularly I would love to own the AIL Storm MK II:

This is what I keep trying to tell people.

They keep telling me, "Well you can get a Cummins R2.8" swap for 9k".

I tell them yeah, you can, but that's far from a "complete" swap, and you're going to end up spending around 15k or more to put it in there and do it right, especially if you're paying a shop.

Costs add up quick, that's for sure.

Yep. The key words are right and swap. Conversion may convey what you're trying to accomplish. I do think for Apples to Apples R2.8 vs brand new crate motors, it's a great swap and the extra up front cost will be made up by fuel and trying to leave some stock components intact, but it isn't going to be $9k.

If you're a builder with lots of stuff and parts around and time to search junkyards, you could do it pretty cheap after you have the engine, but that's not most people that are looking to do this conversion.

Yeah I guess I should add that my $3500 is the bare minimum to get the Kubota Diesel into the Wrangler, but you should barely add another $250 for miscellaneous pieces. My cost is slightly higher because of some other parts that I decided to get, but they are by no means needed nor required for the swap.

Thanks
Grant

 

[Chris]

Thank you! Also I agree with you about the import as well!!! There were several Wrangler models sold overseas not in the states that I would love to owner. Particularly I would love to own the AIL Storm MK II:

View attachment 63543





Yeah I guess I should add that my $3500 is the bare minimum to get the Kubota Diesel into the Wrangler, but you should barely add another $250 for miscellaneous pieces. My cost is slightly higher because of some other parts that I decided to get, but they are by no means needed nor required for the swap.

Thanks
Grant

How loud is that Kubota? Is it one of those rattle your brains out diesels like the 4BT?

 

[RustyAutoholicGuy]

How loud is that Kubota? Is it one of those rattle your brains out diesels like the 4BT?

Honestly it's surprisingly quiet. Here is a video of my testing my V2403:

Project Felicity - 01 - Kubota V2403 Engine Test Run

What really surprised me about it was how quiet the diesel engine was with no exhaust on it at all. Also the longer I ran the motor the smoother the engine got as well. I did run it one more time where I revved the V2403 a couple of times and it really wasn't that loud again no exhaust at all, it didn't seem to hurt my ears at all when I was running it.

I've had V8 and V6 run really quick with no mufflers on them that were louder at idle than this engine was. So I guess I would say it's difficult to say preciously, but I figure once I get the engine in the TJ, and have it connected to a cat and muffler, it's not going to be that loud at all.

It's by no means a 4BT, those engines I believe are 750lbs and the Kubota V2403 is 414lbs, so you have around 350 pounds less running and trying to vibrate.

Another thing to consider is a 4BT was originally made from 1984 to 1998, the Kubota 03 series started production in the early 2000s, my V2403 is from 2007, so you are looking at 20+ years of new diesel technology.

Let me know if you have any more questions!!!!

Thanks
Grant

 

[Chris]

Honestly it's surprisingly quiet. Here is a video of my testing my V2403:

Project Felicity - 01 - Kubota V2403 Engine Test Run

What really surprised me about it was how quiet the diesel engine was with no exhaust on it at all. Also the longer I ran the motor the smoother the engine got as well. I did run it one more time where I revved the V2403 a couple of times and it really wasn't that loud again no exhaust at all, it didn't seem to hurt my ears at all when I was running it.

I've had V8 and V6 run really quick with no mufflers on them that were louder at idle than this engine was. So I guess I would say it's difficult to say preciously, but I figure once I get the engine in the TJ, and have it connected to a cat and muffler, it's not going to be that loud at all.

It's by no means a 4BT, those engines I believe are 750lbs and the Kubota V2403 is 414lbs, so you have around 350 pounds less running and trying to vibrate.

Another thing to consider is a 4BT was originally made from 1984 to 1998, the Kubota 03 series started production in the early 2000s, my V2403 is from 2007, so you are looking at 20+ years of new diesel technology.

Let me know if you have any more questions!!!!

Thanks
Grant

All I can say is that you’re really tempting me with this swap. My only concern would be the low horsepower. One of my biggest issues with the 4.0 is that it has the torque to get there, but it doesn’t have the horsepower to stay there. The 4.0 has 195hp I believe they claim, but it’s more like 135hp at the wheels.

 

[RustyAutoholicGuy]

All I can say is that you’re really tempting me with this swap. My only concern would be the low horsepower. One of my biggest issues with the 4.0 is that it has the torque to get there, but it doesn’t have the horsepower to stay there. The 4.0 has 195hp I believe they claim, but it’s more like 135hp at the wheels.

So I was concerned about that as well, but you have to realize there is a massive difference between the hp and torque curve of our 4.0L and the Kubota V2403 and really between a gas and a diesel engine in general.

Here is the best one I could find for our 4.0l:

Now this was at the wheels so it's a little bit off, but you can clear see below 2000rpm which would be where you would "cruise", a stock 4.0L only has about 50 ~ 60hp and around 155 ~ 160 ft-lb of torque.

Now let's take a look a the Kubota Diesel:

Again this is a stock turbo V2403 which I believe is 4 PSI and I'm going to be pushing around 25 ~ 28 PSI of boost through an intercooler to this engine. First off check out that torque curve. It's in newton meters but even with the bigger turbo, the torque curve is going to basically look the same, just with significantly more torque from 1300 ~ 2800rpm. The HP is going to go through the same pattern as well, you will have more horsepower and torque at EACH RPM level with a Kubota diesel compared to a 4.0L gas engine.

Yes add a Bank's turbo kit to your 4.0L and you will have more PEAK horsepower and probably the same torque. However if you were to compare WHERE the RPMs are when you get that horsepower and torque, the Kubota diesel will have out matched the horsepower and torque at lower RPMs where you would be cruising around.

I notice this EVERYDAY I drive my 2006 Turbo Diesel Jeep Liberty. Once my Liberty hit's 5th gear (overdrive) it's not coming out unless I go below like 48mph because it's using torque to keep me moving, not horsepower (though in all reality it's a mixture of both).

My brother borrowed my Liberty and trailer to move from VA to NC, and when he got back he said it was both weird and awesome how when it hit 5th gear and turned on cruise control, even when climbing steep Virginia hills, the Liberty just stayed in 5th gear and never lost more than 1mph of speed.

I have a hill close to my house where I go up it all the time in low rpm in 5th in my Liberty no issues at all. In my Wrangler it would have to downshift into 3rd to go up the hill. In my wife's 2017 Jeep Renegade that thing has 9 gears and I swear it goes down like 4 gears to go up that hill. *Sidenote* My wife loves her Jeep Renegade and I'm delighted to have her driving a Jeep as her daily!!!!

Didn't mean for this post to be so long, but it took me owning a Turbo Diesel Jeep Liberty to realize the massive difference between Diesel and Gasoline engines. I fully expect once I have this swap done to go up that hill near my house and have it the transmission in 4th gear/overdrive with the torque convert locked and to climb the hill with no issues at all because I'll be at 55mph at around 2100rpm which will be giving me around 300ft-lbs of torque compared to my 4.0l giving me about 155ft-lbs of torque.

Thanks!!!!
Grant

 

[BugoutJeep]

I have 162 hp and get there much faster with 307 fl lbs than the 4.0 and can hold better than my 5.2L V8, though in a ZJ with an Auto. Or a 4.6L V8 in an F150, those V8s have to shift much more to maintain speed and they've got more HP than the 4.0. If you can get them close to the rev limiter they're fine, but nothing like the R2.8 1500-2k RPMs.

 

[BugoutJeep]

Oh and I can second how quiet the turbo diesels are. I have no exhaust except a passive DOC and it's quieter than my 4.0 before I swapped it out, but louder than one with a proper exhaust, but not that a whole lot more. There's a distinctive whine from the turbo that's not quiet, but kinda nice to hear. I was driving around with hearing protection, but after I put my dash back in, a lot of it is tire noise, but certainly not all of it.

 

[RustyAutoholicGuy]

Oh and I can second how quiet the turbo diesels are. I have no exhaust except a passive DOC and it's quieter than my 4.0 before I swapped it out, but louder than one with a proper exhaust, but not that a whole lot more. There's a distinctive whine from the turbo that's not quiet, but kinda nice to hear. I was driving around with hearing protection, but after I put my dash back in, a lot of it is tire noise, but certainly not all of it.

BTW what diesel engine is in your TJ? Just went through the thread and didn't see what you had swapped in!

Thanks
-Grant

 

[BugoutJeep]

I have the R2.8 Cummins with Axis Industries conversion kit.

 

[BugoutJeep]

I assume if you're running mechanical that you also get the benefit of WVO mixtures as well if you want to add in a bonus fuel. Common-rail likes Biodiesel blends, but WVO is likely a bit too thick and filtration could be a bigger issue I guess.

 

[RustyAutoholicGuy]

I have the R2.8 Cummins with Axis Industries conversion kit.

NICE! I really was excited to hear about the Cummins R2.8L but the price tag just really killed it for me. I first got the idea of a diesel swap years ago when I saw a TDI TJ for sale and then I saw the Dirt Every Day episode where they swapped the prototype R2.8. I really wanted one until I saw the price. The cost of it plus the adapters and all the other parts just put it clearly out of my price range at least for this project.

I assume if you're running mechanical that you also get the benefit of WVO mixtures as well if you want to add in a bonus fuel. Common-rail likes Biodiesel blends, but WVO is likely a bit too thick and filtration could be a bigger issue I guess.

I didn't have any plans for WVO honestly, not at this time at least. There are several places near where I live that sell bio-diesel blends which I was considering running as well in my swap.

Thanks
Grant