Anyone seriously considering the R2.8? (Cummins)

[Chris]

Oh and I can second how quiet the turbo diesels are.

But that's not all turbo diesels. I took a ride in a TJ with a 4BT in it, and that thing was do friggin' loud with the top and doors off that I think I got a headache!

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:

View attachment 63565

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:
View attachment 63566

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

I think my only issue I would face at this point is I would want to adapt it to a 4L60E GM transmission most likely (I prefer an automatic), and I'm not 100% sure they make an adapter for this.

The other issue is wiring. Does this engine have a ECU? If so, how do you get it to talk to the Jeep PCM? In addition, is it possible for it to work with the factory gauge cluster, or is that something that hasn't been figured out yet?

 

[RustyAutoholicGuy]

But that's not all turbo diesels. I took a ride in a TJ with a 4BT in it, and that thing was do friggin' loud with the top and doors off that I think I got a headache!



I think my only issue I would face at this point is I would want to adapt it to a 4L60E GM transmission most likely (I prefer an automatic), and I'm not 100% sure they make an adapter for this.

The other issue is wiring. Does this engine have a ECU? If so, how do you get it to talk to the Jeep PCM? In addition, is it possible for it to work with the factory gauge cluster, or is that something that hasn't been figured out yet?

Heheheh wrong again, Ken from KubotaSwappers makes a Small Block Chevy and Small Block Ford adapter. Basically his kits makes the Kubota engines look like the adapter he sells. So the kit I have makes my Kubota look like a 4.0L in terms of the crankshaft and bellhousing bolts. His Small Block Chevy and Ford kits make the Kubotas look like a Chevy or Ford V8.

No ECU on the wiring at all, it's completely mechanical. I'm running a Cherokee XJ AW4 4 speed automatic though I just sent USShift a question about their Quick 4 Stand-alone Transmission Controller, I would like to keep the 42RLE for the lower overdrive gear and the Rubi-Crawler you can add to it between the the transmission and transfer case.

So yeah Ken makes adapters I believe for Jeep, Toyota, Chevy and Ford, and he's probably working on others if I had to guess.

Also the 4BT is a monster of an engine, and it's 80s diesel technology, the Kubota engines are 2000s tech and the R2.8 Cummins is even newer! I wouldn't want to run a 4BT or a Mercedes engine in my TJ. I would run a Mercedes Diesel in a CJ-7 or CJ-8 Scrambler but mostly because the same technology is being used in both, but I'm weird like that!

-Grant

 

[BugoutJeep]

Sorry Chris, I meant the modern turbo diesels are typically much more quiet. That being said I was around some equipment in a plant with a 4BT in it and it was pretty mild mannered and propane fork lifts stunk more than this thing, until the hydraulics started leaking and it wasn't as mild mannered.

 

[Chris]

Heheheh wrong again, Ken from KubotaSwappers makes a Small Block Chevy and Small Block Ford adapter. Basically his kits makes the Kubota engines look like the adapter he sells. So the kit I have makes my Kubota look like a 4.0L in terms of the crankshaft and bellhousing bolts. His Small Block Chevy and Ford kits make the Kubotas look like a Chevy or Ford V8.

No ECU on the wiring at all, it's completely mechanical. I'm running a Cherokee XJ AW4 4 speed automatic though I just sent USShift a question about their Quick 4 Stand-alone Transmission Controller, I would like to keep the 42RLE for the lower overdrive gear and the Rubi-Crawler you can add to it between the the transmission and transfer case.

So yeah Ken makes adapters I believe for Jeep, Toyota, Chevy and Ford, and he's probably working on others if I had to guess.

Also the 4BT is a monster of an engine, and it's 80s diesel technology, the Kubota engines are 2000s tech and the R2.8 Cummins is even newer! I wouldn't want to run a 4BT or a Mercedes engine in my TJ. I would run a Mercedes Diesel in a CJ-7 or CJ-8 Scrambler but mostly because the same technology is being used in both, but I'm weird like that!

-Grant

Do you think you could actually get a 42RLE to work with it, being as though the 42RLE is controlled by the PCM?

So I take it you can't use the factory gauge cluster in that case then, right?

I just looked at the site, and you're right, he does have an adapter for those GM transmissions, so that's pretty cool!

 

[RustyAutoholicGuy]

Do you think you could actually get a 42RLE to work with it, being as though the 42RLE is controlled by the PCM?

So I take it you can't use the factory gauge cluster in that case then, right?

I just looked at the site, and you're right, he does have an adapter for those GM transmissions, so that's pretty cool!

I think if you get a 2004 TCM before Jeep integrated it in 2005 you could probably get it to work. However I'm still waiting to hear back from USShift to see if their control could be made to work with the 42RLE transmission. I would much rather go with an aftermarket transmission controller than try to splice into a factory one, especially for the upshift and downshift logic around the RPM limits of the diesel engines.

As for gauges I think you could make them work honestly, but I opted to go with Intellitronix digital gauges and Autometer's Gauge Mounting Solution for TJs.

-Grant

 

[BugoutJeep]

Well I'm really interested to see a fairly modern mechanical diesel, but I want to see some others find the pitfalls and the solutions first. In a few years maybe I can truly finish up my Jeep how I want it.

The R2.8 Cummins is a nice engine, but from an engineering perspective that's not an engine designer, I'm not sure there's been any improvements since the early 2000's except for emissions related equipment, at least for the typical end user. Plastics are probably better and routing wiring is probably a bit better. It might be easier for me to go to Cummins though and have them diagnose problems, but I'm not sure.

That being said, I'm not sure there's a more attainable common-rail diesel in the US for the average gear head with basic tools. CRD is probably the key phrase there, but they're a bit more flexible than any mechanical diesel I've seen. They have good RPM range, pretty good efficiency throughout the RPM range, and I'm going to guess that maybe cold starts are easier, but I don't know.

I feel like maybe we're hi-jacking this thread though, but I'm kinda new to forums.

 

[RustyAutoholicGuy]

Well I'm really interested to see a fairly modern mechanical diesel, but I want to see some others find the pitfalls and the solutions first. In a few years maybe I can truly finish up my Jeep how I want it.

The R2.8 Cummins is a nice engine, but from an engineering perspective that's not an engine designer, I'm not sure there's been any improvements since the early 2000's except for emissions related equipment, at least for the typical end user. Plastics are probably better and routing wiring is probably a bit better. It might be easier for me to go to Cummins though and have them diagnose problems, but I'm not sure.

That being said, I'm not sure there's a more attainable common-rail diesel in the US for the average gear head with basic tools. CRD is probably the key phrase there, but they're a bit more flexible than any mechanical diesel I've seen. They have good RPM range, pretty good efficiency throughout the RPM range, and I'm going to guess that maybe cold starts are easier, but I don't know.

I feel like maybe we're hi-jacking this thread though, but I'm kinda new to forums.

Hehehehe I'm new here as well, but I think our discussion is valid.

I love my CRD in my Liberty but I get nervous every-time I go to work on it. The timing belt system could have been made so much better without the need for a $600 tool to hold the gears in place. I will never understand why they didn't key the cam gears on the CRD.

Cold starts are pretty good, I've never not had it start, and yes the RPM range is good and for how heavy the Liberty is, I think mine is like 4500lbs, it does great to average around 28.5 ~ 30.5 mpg.

I'm looking forward to seeing what the driving differences are between the my CRD and the Kubota!

Hey @DieselJeep maybe once I get my project done and on the road we can meet up sometime on a trail and check each other rigs out! I imagine they are going to be vastly different from each other!

-Grant

 

[BugoutJeep]

Hehehehe I'm new here as well, but I think our discussion is valid.

I love my CRD in my Liberty but I get nervous every-time I go to work on it. The timing belt system could have been made so much better without the need for a $600 tool to hold the gears in place. I will never understand why they didn't key the cam gears on the CRD.

Cold starts are pretty good, I've never not had it start, and yes the RPM range is good and for how heavy the Liberty is, I think mine is like 4500lbs, it does great to average around 28.5 ~ 30.5 mpg.

I'm looking forward to seeing what the driving differences are between the my CRD and the Kubota!

Hey @DieselJeep maybe once I get my project done and on the road we can meet up sometime on a trail and check each other rigs out! I imagine they are going to be vastly different from each other!

-Grant

Is the CRD a timing belt? How's the timing done on the Kubota?

When it's time for the Cummins timing chain to be done, I'm taking the engine to Cummins for a full rebuild. Timing chain is not easy to replace on the Cummins. The real question and the simple answer is that timing gears should be used, but those few hundred dollar more parts from the factory and the incredible engine life vs the other components as a result is likely the answer.

I believe the Cummins 3.8 does have geared timing, but Cummins is so plastic happy that there's some issues with those motors from what I've heard.

Yeah I'd love to see your project. I need to find some nice trails within a few hours drive time. Of course I don't like to do much that could result in a tow truck home either. I like rock climbing, but not in my vehicle.

 

[RustyAutoholicGuy]

Is the CRD a timing belt? How's the timing done on the Kubota?

When it's time for the Cummins timing chain to be done, I'm taking the engine to Cummins for a full rebuild. Timing chain is not easy to replace on the Cummins. The real question and the simple answer is that timing gears should be used, but those few hundred dollar more parts from the factory and the incredible engine life vs the other components as a result is likely the answer.

I believe the Cummins 3.8 does have geared timing, but Cummins is so plastic happy that there's some issues with those motors from what I've heard.

Yeah I'd love to see your project. I need to find some nice trails within a few hours drive time. Of course I don't like to do much that could result in a tow truck home either. I like rock climbing, but not in my vehicle.

Yeah the CRD is a timing belt, I've had to change mine twice now on my Liberty and it's a pain. The Kubota is a gear driven which means once I get my Wrangler on the road I'm going to drive it way more than my Liberty to delay doing the timing belt for a 3rd time!

Honestly I'd be happy with a chain if I could get a chain on the CRD, belts just scare me, you snap a belt and then you are having to replace all the rocker arms which are designed to fail if the timing belt fails, but that's another $800 in parts to fix!

Agreed on the light trails! I'd just want to see how the two TJs with different diesels handle everything!

-Grant

 

[BugoutJeep]

Grant,

What intercooler are you looking to run for the Kubota?

I'm interested in sizing as well. I read a book more than a decade ago on turbo systems, but don't remember too much. I want to say on the R2.8 a big need for the intercooler (CAC) is for the emissions equipment.

My current intercooler, I would think is massive and before the update from Cummins I felt like maybe when shifting certain gears, that maybe I didn't have the boost pressure. It could just be how I'm more used to my 5.9 Cummins and not a smaller turbo diesel.

 

[RustyAutoholicGuy]

Grant,

What intercooler are you looking to run for the Kubota?

I'm interested in sizing as well. I read a book more than a decade ago on turbo systems, but don't remember too much. I want to say on the R2.8 a big need for the intercooler (CAC) is for the emissions equipment.

My current intercooler, I would think is massive and before the update from Cummins I felt like maybe when shifting certain gears, that maybe I didn't have the boost pressure. It could just be how I'm more used to my 5.9 Cummins and not a smaller turbo diesel.

So the intercooler I'm going to be running is a 3" inlet/outlet that I got off eBay years ago for another project that I ended up never doing. I want to say it's 18X12X3 for the dimensions. Last time I checked it should just about fit perfectly inside the grill once I remove the aftermarket transmission cooler.

The RPM and boost drop has been a bit of a concern on my end as well but I'm running the turbo setup that KubotaSwappers recommends, a Borg Warner K03, so it should spool with almost no lag. Oddly enough I know some guys are running compound turbo setups on these 03 series diesel engines, I'd like to stay away from that level of complexity at all possible, especially for a first diesel build/swap but down the road if I'm not happy with the low end power, I could see myself going to a compound setup.

I fully expect to get the Kubota in the Wrangler and drive it around knowing I'm going to have to change things to get it to behave the way I want it to!

-Grant

 

[BugoutJeep]

I really don't mind belts, but it's about the design. I have read from some stuff from New Zealand, South Africa, or something and some of those guys were saying that the newish Toyota diesel motors were designed to swap the belts in like 30 minutes to an hour or something.

On the 2.8, I've had to take off a couple of components and I must say those parts have been designed well and everything has had o-rings and o-ring grooves. However, you have to pull the engine to do the timing chain. At least it has great lifting lugs.

 

[BugoutJeep]

Did you do anything to the engines you got? Any freshening up of the internal components/head studs, etc?

 

[RustyAutoholicGuy]

I really don't mind belts, but it's about the design. I have read from some stuff from New Zealand, South Africa, or something and some of those guys were saying that the newish Toyota diesel motors were designed to swap the belts in like 30 minutes to an hour or something.

On the 2.8, I've had to take off a couple of components and I must say those parts have been designed well and everything has had o-rings and o-ring grooves. However, you have to pull the engine to do the timing chain. At least it has great lifting lugs.

WOW an hour to do a belt swap would be amazing! You can do the CRD in a day but it's going to be like 10 hours. You have to remove the radiator, clutch fan (I now have an electric fan which makes it easier), and pretty much all the accessories minus the AC compressor. I honestly don't mind doing all that though, it's the fact that there are not timing marks on the engine and also the cam gears are torque press to the cams, so if you let them turn or loose your marks for putting the cam gears back on, it's basically an engine tear down to get your base timing back again.

Did you do anything to the engines you got? Any freshening up of the internal components/head studs, etc?

Some other guys that are doing massive boost do head studs but other than that no, pretty much just running the factory components. I've replaced a couple of small things but nothing major. I thought about replacing the head studs with ARP, but when I ran my compression check on each cylinder it was within 2 ~ 4 psi of what the manual said was brand new so I didn't want to take it apart.

-Grant

 

[BugoutJeep]

I've never really done any motor work on a diesel. Ancillary type stuff only and luckily everything I've had and family has had has been fine.

It is scary for those guys I know that have had issues. Most people that have issues with newer stuff are trying to blow them up though, so what do you expect. One buddy did get a skid steer and after running it for a month realized the block was cracked. That sucked, but so far the weld has held. The engine or the block was some kind of ridiculous price.

Yeah some of these companies suck when it comes to timing work. I guess they realize it won't typically happen during warranty so they just make more money the longer it takes and the more specialty tools that are required. A buddy of mine does the TDI belt swaps all the time and made a bunch of tools for it and some of the injection stuff, but it sounds like a pain.

I actually briefly looked at getting one of the modern Toyota turbo diesels for my swap. The problem was that you'd pretty much need a vehicle half to do it from my understanding so the initial price on a used setup was very high and then you're still fabricating everything to fit. I do like the CAC overhead on the engine. I think this would look cool as well with a hood scoop. This may have a lot of advantages for a swap as well if maybe you could keep the routing away from the grill area and try to keep that more stock. Just a thought.

 

[RustyAutoholicGuy]

I've never really done any motor work on a diesel. Ancillary type stuff only and luckily everything I've had and family has had has been fine.

It is scary for those guys I know that have had issues. Most people that have issues with newer stuff are trying to blow them up though, so what do you expect. One buddy did get a skid steer and after running it for a month realized the block was cracked. That sucked, but so far the weld has held. The engine or the block was some kind of ridiculous price.

Yeah some of these companies suck when it comes to timing work. I guess they realize it won't typically happen during warranty so they just make more money the longer it takes and the more specialty tools that are required. A buddy of mine does the TDI belt swaps all the time and made a bunch of tools for it and some of the injection stuff, but it sounds like a pain.

I actually briefly looked at getting one of the modern Toyota turbo diesels for my swap. The problem was that you'd pretty much need a vehicle half to do it from my understanding so the initial price on a used setup was very high and then you're still fabricating everything to fit. I do like the CAC overhead on the engine. I think this would look cool as well with a hood scoop. This may have a lot of advantages for a swap as well if maybe you could keep the routing away from the grill area and try to keep that more stock. Just a thought.

Hadn't thought about a hood scope honestly. I liked the grill options just for the amount of fresh air hitting the intercooler to cool down the charged air. I had really considered going with a water to air setup, but it was going to add so much cost to the build that I just didn't want to spend right now.

-Grant

 

[BugoutJeep]

Depending on the engine height, overhead gives some advantage with routing CAC tubing. You won't get good airflow off-road, but it's supposed to be fine on-road. Typically this isn't much of an issue for TJs, since they were designed with an inline 6 as the stock motor and large mechanical fan. But say you wanted a longer engine like the 5 cylinder engines and wanted AC, Auto, etc, maybe this would be handy.

In any case it's probably just from Toyota trying shove so much stuff under their hoods as the only reason you'd consider it.

 

[RustyAutoholicGuy]

Depending on the engine height, overhead gives some advantage with routing CAC tubing. You won't get good airflow off-road, but it's supposed to be fine on-road. Typically this isn't much of an issue for TJs, since they were designed with an inline 6 as the stock motor and large mechanical fan. But say you wanted a longer engine like the 5 cylinder engines and wanted AC, Auto, etc, maybe this would be handy.

In any case it's probably just from Toyota trying shove so much stuff under their hoods as the only reason you'd consider it.

Yeah I think I have room, I won't know until later this weekend honestly. I'm working on getting the engine/transmission/transfer case out today and I'm looking to mock up where the the V2403/AW4 and NP231 will be when I go to put them in. I know the F2503 and F2803 are shorter than the 4.0l so you would still have some room on the front, I just can't wrap my head around a hood scope I guess.

Also I think that going to a water to air setup in the future would be great for off-road as well because you could have a pusher or puller fan on the water to air radiator which would help immensely.

-Grant

 

[BugoutJeep]

I wouldn't be worrying about emulating the Toyota. As far as engine length, my radiator is probably an inch or thicker more than OEM, and then add a 3in thick intercooler and there's still plenty of room, but side to side is a different story. Vertically and in the front is where the room is, but most diesels are probably taller than the 4.0.

I think some people making custom adapters are moving the trans and everything forward. On the r2.8 the biggest issue is the stock placement of the DOC as it wants to hit one of the control arms. The DOC and egr are basically what force most r2.8s in their positions. Probably eliminating those would make routing a bit easier if I were to guess. Now that my mounts are welded and I'm using stock trans mount the only thing in the way is the EGR. It's like duct taping a battery to the head. And every wire and hose back there is pretty close to the turbo.

Hence when warranty is up, it's going away and I'll finalize wiring. I don't mind the DOC but I suspect rock crawlers will have to address it.
And added bonus could be a 10% increase in efficiency once tuned out, better engine life, more room, less weight, less cooling needed, etc. I tried to find technical articles as well to support the efficiency loss and added logistics to attain that additional resource vs the decrease in emissions and really haven't found anything to support that egr is that useful on ulsd diesel applications in reducing overall emissions NET. Maybe it does but I can't seem to find it. I typically only find articles to the contrary. Sorry about the rant, just don't want someone to think I'm going to take something out of the system without trying to find the consequences.

 

[mine]

I'm curious to see if anyone is seriously considering doing this. At the end of my build I have full intentions of doing something to my engine and considering all options. It seems like it would be a smart switch for fuel economy but a poor switch for power. I'd love to see someone do a build thread of one on here!

only on days when i have nothing else to do and think about when I might have $9k to waste - when the math is done and it is one of 2 scenarios - wither my powertrain is done and needs overhaul or I just want to blow some she money - - so if my engine is done for and I need newer - the cost diff between repairs, new gas vs new diesel (2.8) labor and xtra parts being equal - the mpg savings is about 5-8 per gallon - so when looking at diesels - that means I would have to drive 62K miles to break even - and 3 yrs if my daily driver - maybe I say yes - if not a daily driver and just weekends - that break even goes to 8-10 yrs -
but this is just me - spreadsheet says no - but that really isn't why i have a jeep is it - living true to "Just Empty Every Pocket".....I started my 2.8 acct 1 yr ago and am 1K deep - so 7k more then my baby will get a Diesel - just bc I have the money to burn and the long 2 weekends to pull and stab - and my 6 is still humming so I will do it just bc I want to - maybe - I am on the fence ........don't need it but maybe just maybe they will go on sale