Building a diesel powered RHD TJ Wrangler (Picture Heavy)

[RustyAutoholicGuy]

Just curious, what do you think the top speed of this motor is going to be on your jeep. Not looking for racing but wondering about if it has the ability to go on the highway or interstate going 70-75 mph. If so this sounds like the perfect engine to swap! Increased torque, I think you said it was lighter as well, muuuuucchhh better fuel economy, can still be used on the highway, and best of all it is one of the cheaper swaps out there.

Great question! So with my current planned setup I should, if needed, be able to do 80mph which would have me spinning the Kubota at 2600rpm but I have no desire to spin the little diesel that hard. Also I've never done 80mph in a Wrangler and I have no desire to try either!

I know from doing all my research the engine has a happy sweet spot between like 1800~2250rpm for fuel economy which is kind of where all my highway speeds are going to land. 55mph is going to be at 1789rpm, 65mph is going to be at 2114rpm and 70mph is going to be at 2277rpm.

75mph should push the engine to like 2439mph so I'll be able to pass people on the highway if I need to but mostly I'll be keeping myself in the slow lane and cruising at the speed limit getting fantastic fuel economy!

Yeah the weight is surprising, at only 425ish pounds it's a light motor which is nice, it means I don't have to worry about my suspension for the time being, I can just focus on getting the swap figured out!!!

Thanks
-Grant

 

[Calvin.8]

Great question! So with my current planned setup I should, if needed, be able to do 80mph which would have me spinning the Kubota at 2600rpm but I have no desire to spin the little diesel that hard. Also I've never done 80mph in a Wrangler and I have no desire to try either!

I know from doing all my research the engine has a happy sweet spot between like 1800~2250rpm for fuel economy which is kind of where all my highway speeds are going to land. 55mph is going to be at 1789rpm, 65mph is going to be at 2114rpm and 70mph is going to be at 2277rpm.

75mph should push the engine to like 2439mph so I'll be able to pass people on the highway if I need to but mostly I'll be keeping myself in the slow lane and cruising at the speed limit getting fantastic fuel economy!

Yeah the weight is surprising, at only 425ish pounds it's a light motor which is nice, it means I don't have to worry about my suspension for the time being, I can just focus on getting the swap figured out!!!

Thanks
-Grant

Wow that's awesome! I was looking around for the engine last night to see what the pricing was like and if I am correct, it seems like there is multiple versions of the V2403?

 

[RustyAutoholicGuy]

Wow that's awesome! I was looking around for the engine last night to see what the pricing was like and if I am correct, it seems like there is multiple versions of the V2403?

Yes thee are so here is the breakdown of how the Kubota labeling system works, I'll use the V2403 to show!

The V stands for the number of cylinders the engine has. The most common I have found are D, V, and F. D is a 3 cylinder, V is the 4 cylinder and F is the 5 cylinder.

The 24 stands for displacement. So my Kubota engine is a 2.4l because it's a V2403. I also have a V1903 which means it's a 1.9l.

Finally the last two numbers at the engine series from Kubota. So in this case it's the 03 series of engines. That is almost more important than anything else when looking for an engine to do this swap because all the adapters I have ever found for Kubota engines are for the 03 series of engines!!!

Here are all the 03 series of 4 cylinder engines that I know about and I have seen. You have the V1903, V2003, V2203 and the V2403. I got extremely lucky when I found my V2403, it was the right price and I just completely lucked out!

The most common engine you will find is the V2203 and I would say the next most common engine would be the V2003. I somehow found the oddball motors with the V1903 and V2403!

Now that being said there is also an F2503 and F2803. A 2.5l and 2.8l 5 cylinder diesel engine! I've only ever seen one for sale, the 2.8l and I just didn't have the funds at the time to pick it up. They are extremely expensive from what I've been able to tell.

The other thing you need to know is there are two types of these diesel engines, an IDI and a DI. IDI stands for Indirect Injection and DI stands for Direct Injection. A DI motor makes 15% more horsepower and torque than an IDI motor. Both of my Kubota engines are IDI which is fine. I think a V2203 DI would make more horsepower and torque than my V2403 when turbo charged and tuned.

So in a perfect world I would find a V2203 DI motor. You have to look at the label on the top of the valve cover and search for the model number which is like V2203-EQ3 (I made up the last part just FYI) to see if it's an IDI or DI. There is a way to tell by looking at how the injectors are held down to the head of the engine but I can never remember what it is honestly.

In terms of price I wouldn't pay more than about $1300 for an IDI motor and no more than $2000 for a DI motor but that's a personal preference. Ebay always has the engines but they are higher in price. I've found my two engines on Craigslist and Facebook. I bought my V1903 for $800 and my V2403 with shipping was right around $1500.

Hope this helps and let me know if you have anymore questions!

Thanks
Grant

 

[Calvin.8]

Yes thee are so here is the breakdown of how the Kubota labeling system works, I'll use the V2403 to show!

The V stands for the number of cylinders the engine has. The most common I have found are D, V, and F. D is a 3 cylinder, V is the 4 cylinder and F is the 5 cylinder.

The 24 stands for displacement. So my Kubota engine is a 2.4l because it's a V2403. I also have a V1903 which means it's a 1.9l.

Finally the last two numbers at the engine series from Kubota. So in this case it's the 03 series of engines. That is almost more important than anything else when looking for an engine to do this swap because all the adapters I have ever found for Kubota engines are for the 03 series of engines!!!

Here are all the 03 series of 4 cylinder engines that I know about and I have seen. You have the V1903, V2003, V2203 and the V2403. I got extremely lucky when I found my V2403, it was the right price and I just completely lucked out!

The most common engine you will find is the V2203 and I would say the next most common engine would be the V2003. I somehow found the oddball motors with the V1903 and V2403!

Now that being said there is also an F2503 and F2803. A 2.5l and 2.8l 5 cylinder diesel engine! I've only ever seen one for sale, the 2.8l and I just didn't have the funds at the time to pick it up. They are extremely expensive from what I've been able to tell.

The other thing you need to know is there are two types of these diesel engines, an IDI and a DI. IDI stands for Indirect Injection and DI stands for Direct Injection. A DI motor makes 15% more horsepower and torque than an IDI motor. Both of my Kubota engines are IDI which is fine. I think a V2203 DI would make more horsepower and torque than my V2403 when turbo charged and tuned.

So in a perfect world I would find a V2203 DI motor. You have to look at the label on the top of the valve cover and search for the model number which is like V2203-EQ3 (I made up the last part just FYI) to see if it's an IDI or DI. There is a way to tell by looking at how the injectors are held down to the head of the engine but I can never remember what it is honestly.

In terms of price I wouldn't pay more than about $1300 for an IDI motor and no more than $2000 for a DI motor but that's a personal preference. Ebay always has the engines but they are higher in price. I've found my two engines on Craigslist and Facebook. I bought my V1903 for $800 and my V2403 with shipping was right around $1500.

Hope this helps and let me know if you have anymore questions!

Thanks
Grant

Yes, this helps a lot!!! A diesel swap may be coming sooner than I thought now knowing I don't have to drop 10 grand on a Cummins R2.8

 

[RustyAutoholicGuy]

Yes, this helps a lot!!! A diesel swap may be coming sooner than I thought now knowing I don't have to drop 10 grand on a Cummins R2.8

I really like the Cummins R2.8l ESPECIALlY for people that live in California or other emissions strict areas. Yes it's expensive and I kind of keep hoping the price will come down a bit, but I understand the price tag! At least there is now a 100% legal diesel engine swap for all Jeep owners and for that I really like the engine!

 

[Chris]

This is such a better option than the 4BT swap. I always hear people saying, "I want to swap a 4BT in my TJ", and I'm always trying to steer them away from it. That engine is loud as hell, it's heavy as hell, and IMHO it doesn't belong in a Jeep. It's not a bad engine, I just don't think that it's an ideal engine for a Wrangler is all.

This Kubota or the Cummins R2.8 are the better choices by far.

 

[RustyAutoholicGuy]

This is such a better option than the 4BT swap. I always hear people saying, "I want to swap a 4BT in my TJ", and I'm always trying to steer them away from it. That engine is loud as hell, it's heavy as hell, and IMHO it doesn't belong in a Jeep. It's not a bad engine, I just don't think that it's an ideal engine for a Wrangler is all.

This Kubota or the Cummins R2.8 are the better choices by far.

Admittedly at one time I wanted a 4BT until I realized just how massive of an engine it is!

On another note we got snow here in Virginia!!! On the plus side been having a great time with my kids!!! On the down side I was suppose to have a TON of parts coming today . . . oh well.

-Grant

 

[Calvin.8]

I'm still a ways away from being able to afford a swap. And I have other projects I want to do to my jeep first anyway (I'm still in high school playing sports so money is not coming quickly). So by the time I'm ready to do a diesel swap, I'll probably make my decision of either the R2.8 or the Kubota based on my budget at the time. Because if I can afford the R2.8 that would be awesome to have. It's just nice to know if I can't afford that, there are more affordable paths to take.

 

[RustyAutoholicGuy]

I'm still a ways away from being able to afford a swap. And I have other projects I want to do to my jeep first anyway (I'm still in high school playing sports so money is not coming quickly). So by the time I'm ready to do a diesel swap, I'll probably make my decision of either the R2.8 or the Kubota based on my budget at the time. Because if I can afford the R2.8 that would be awesome to have. It's just nice to know if I can't afford that, there are more affordable paths to take.

Agreed with everything! In a way I wish I had gotten my first Wrangler in high school or college, I would have not bought nearly all the vehicles that I have over the past 13 years!!!

 

[StG58]

So, the wife wanted to go Christmas shopping yesterday and I used that as an opportunity to play around with real life engine RPM vs. speed. I didn't take notes on exact RPM though I wish I had now. With my SE and 31 inch tires, it was easy to keep the RPM under 2,800 - 3,000 RPM with the AX-5 all the way up to 70 mph. That's with stock 4.10 gears. (My 2.5 hated it) so, I'm in the ballpark with gearing and tire size.

Started checking into the availability of parts and maintenance supplies. There are more local vendors within 25 miles for Kubota parts than there are liquor stores, and almost more than bars. They seem to use these things in everything around here. But, it's an agricultural area, so go figure.

Next up is to check the gear ratios on the six speed manual, to see if that will buy me a better match to the Kubota power band.

This is very cool!

 

[Calvin.8]

Agreed with everything! In a way I wish I had gotten my first Wrangler in high school or college, I would have not bought nearly all the vehicles that I have over the past 13 years!!!

Yes, it has been very fun to have!! But now I can't wait to get out of school that way I can get a job to pay for Jeep parts haha.

 

[RustyAutoholicGuy]

So, the wife wanted to go Christmas shopping yesterday and I used that as an opportunity to play around with real life engine RPM vs. speed. I didn't take notes on exact RPM though I wish I had now. With my SE and 31 inch tires, it was easy to keep the RPM under 2,800 - 3,000 RPM with the AX-5 all the way up to 70 mph. That's with stock 4.10 gears. (My 2.5 hated it) so, I'm in the ballpark with gearing and tire size.

Started checking into the availability of parts and maintenance supplies. There are more local vendors within 25 miles for Kubota parts than there are liquor stores, and almost more than bars. They seem to use these things in everything around here. But, it's an agricultural area, so go figure.

Next up is to check the gear ratios on the six speed manual, to see if that will buy me a better match to the Kubota power band.

This is very cool!

So looking at the NVG3750 the final gear is either .85 or .83 so that won't really affect your highway/interstate speed too much.

Honestly your Axles Gear Ratio/Tire size is more important because that really affects how your engine and transmission translate their power to the axles.

See for me personally I wouldn't be going to 4.10 gears until I get at least 31 inch tires but only until I went to 33 inch tires.

My end goal is actually 35" tires on my Wrangler so in terms of axle gearing a 4.56 gear set would be best for my setup!

Yes, it has been very fun to have!! But now I can't wait to get out of school that way I can get a job to pay for Jeep parts haha.

Don't make the mistake I made which was I have a better paying job so I'll own more Jeeps!!! At one point last year I had 13 Jeeps on my property!!!

-Grant

 

[StG58]

Ok Grant, this almost looks like a marriage made in heaven.
NSG370 six speed
Rated input torque = 272 ft-lbs. (Turbo IDI engine?)
Rated output torque = 11 - 1300 ft-lbs.
1st = 4.46 : 1
2nd = 2.26 :1
3rd = 1.72 : 1
4th = 1.25 : 1
5th = 1.0 : 1
6th = 0.84 : 1 (overdrive)

4.10 gears and 32-33 inch tall tires look perfect!

 

[Calvin.8]

Don't make the mistake I made which was I have a better paying job so I'll own more Jeeps!!! At one point last year I had 13 Jeeps on my property!!!

-Grant

13! My goodness. My hope is to have 2 jeeps when I get older. My current one for more extreme offroading and get a newer 4 door as more of an overland style jeep. And I've been thinking a lot about careers lately, what do you do?

 

[RustyAutoholicGuy]

Ok Grant, this almost looks like a marriage made in heaven.
NSG370 six speed
Rated input torque = 272 ft-lbs. (Turbo IDI engine?)
Rated output torque = 11 - 1300 ft-lbs.
1st = 4.46 : 1
2nd = 2.26 :1
3rd = 1.72 : 1
4th = 1.25 : 1
5th = 1.0 : 1
6th = 0.84 : 1 (overdrive)

4.10 gears and 32-33 inch tall tires look perfect!

There is a known issue with reverse gear popping out but there is also a fix for it as well so just install it if you are going with the nvg3750!

Also that deep first gear is going to be great off-road. I think you should be pretty happy with your RPM drops between gears with the Kubota Diesel!

Let me ask this first have you ever driven a diesel before?

-Grant

 

[Calvin.8]

So does going to diesel affect the gear ratio you would choose?

 

[StG58]

There is a known issue with reverse gear popping out but there is also a fix for it as well so just install it if you are going with the nvg3750!

Also that deep first gear is going to be great off-road. I think you should be pretty happy with your RPM drops between gears with the Kubota Diesel!

Let me ask this first have you ever driven a diesel before?

-Grant

Only in trucks... We have a Peterbuilt Box van with an Allison automatic in it, and we had an old beater bobtail in the shipyard we used to move steel with. So no, not really. What am I looking at?

 

[Calvin.8]

13! My goodness. My hope is to have 2 jeeps when I get older. My current one for more extreme offroading and get a newer 4 door as more of an overland style jeep. And I've been thinking a lot about careers lately, what do you do?

If you dont mind me asking

 

[RustyAutoholicGuy]

13! My goodness. My hope is to have 2 jeeps when I get older. My current one for more extreme offroading and get a newer 4 door as more of an overland style jeep. And I've been thinking a lot about careers lately, what do you do?

So I'm a Senior QA Automation Engineer. I program automation to test software essential. Nice paying job, I work from home but at the end of the day I don't want to be on a computer anymore.

I'm looking at 3 Jeeps in total and I'm spoiling my next two major projects but I'll go ahead and tell !

So obviously I have my 2006 RHD TJ, this will be my around town Jeep running errand by myself.

My next build is going to be my 1947 CJ-2A. I'm building a frame from scratch and it's looking to be a completely unique off the wall build!

My next build is going to be a Wrangler JKU. I don't own one, but with two kids, and three huskies, a 4 door Wrangler is going to have to be in my future. My kids are small but they are growing VERY quickly so I'm going to need more space sooner rather than later! Also this would be built so I could haul my CJ-2A.

All of these builds will be diesel!

-Grant

 

[RustyAutoholicGuy]

So does going to diesel affect the gear ratio you would choose?

Yes absolutely! Diesels do not have the same RPM or Revving ability that a gasoline engine has. The Kubota has a maximum RPM of like 3100~3300 rpm but I wouldn't spin it faster than 2800rpm personally.

My 2006 Liberty CRD has a redline of 4500rpm but honestly I never take it past 3000rpm, there just isn't a point, let the transmission shift and use the torque to accelerate with the turbo!

Only in trucks... We have a Peterbuilt Box van with an Allison automatic in it, and we had an old beater bobtail in the shipyard we used to move steel with. So no, not really. What am I looking at?

Just that where your 2.5l was struggling, that 2.2l V2203 Kubota engine would excel at and you won't have to spin the engine as hard either! You are going to have so much torque below 2000rpm you aren't going to have to rev the engine hard to make your Wrangler accelerate!

-Grant