1999 Jeep Wrangler 2.2L Kubota diesel swap

crash0099

New member
Hey Red this is a great thread.

Red, I saw a guy put an engine similar to this in a little kit car and he gets around 100mph so ever since then I have had something like this in the back of my mind. This is a great post, no matter what kind of negative comments you get. I have just bought my jeep in the last couple of months and decided to see if anyone had put a Kubota motor in a jeep.... Low and behold. I happen to be in a wheelchair and will have to use an automatic tranny if I ever do this. I really like all the info you have put on here. My jeep happens to have a Chevy V-8 in it and I have some work to do to it. It is an 89 YJ and is only 2 wheel drive due to some crazy work but I am looking to put a new tranny and Transfer case in it so I can use it all. May I ask how much this has cost you so far. I know you can't measure your time, but this is an interesting post so I may start looking for another Jeep to do this to. I am looking forward to you working out the kinks in your new turbo setup too. Do you think this will hurt or help your mileage? Keep this going I am really enjoying this and best of luck with it. I happen to believe in torque over HP when it comes to a jeep. It seems to me a diesel makes more sense any way in a jeep for everything but racing. Well even with the new technoligies they have developed, such as Audi in the LeMans racing. It may make more sense for a jeep down the road for anything.
Craig
 

k9lestat

Expedition Leader
i wonder if something like this could be done in a full size van. maybe with a hi/lo range manual transmission
 

redveloce

Adventurer
I did some playing with it last night, and I think I have it in the ballpark of where I want it tuned.

I've found that it likes the small turbo to stay engaged, so I basically have the wastegate actuator shut off for that one. I left it in, so it can open if the drive pressure gets too high though. It must have been cracking pretty early, because it's helped the bottom end performance a good bit, but it also got back the top end surge of power that it was losing from the gate dumping as soon as the big turbo came online. Now I can't get it to break 1000 degrees EGT, and it does a lot better on the freeway. The only issue left with that is that the wastegate line for the big turbo is pinched between the engine and the compressor, and I can make it spike to 18 PSI if I push it really hard. I'm going to try and get it pulled out of there tonight, then adjust the boost controller to limit it to 16 PSI. I've seen it peak at 18 before with the single turbo, but I'm just worried about stressing the engine too much since the normal operating boost level is so much higher now.

I also have the water/methanol injection ready to come online as soon as I pick up a manual on/off switch so I can disarm the system from the drivers seat. It helps add a little power, but I mainly want it as a safety feature during higher boost levels. If I see EGTs rise instead of drop, I'll cut the methanol out of the mix and just run straight water.

May I ask how much this has cost you so far. I know you can't measure your time, but this is an interesting post so I may start looking for another Jeep to do this to.
It's really hard to estimate since I stopped keeping track after the first engine melted down. At that point I had probably $4500 into it. If I had to guess, I'd say I'm at close to $6000 now, but I would say it could probably be done for about half of that cost.

I've spent a lot of money on tools and fabrication equipment, etc. I've also ended up spending a lot of money on false starts, trial and error, and things that just plain didn't work. A lot of things look good on paper, then work horribly in practice. One thing I've learned is that when a solution starts to look and feel half assed and cludged, it's just not going to work. Another is that temporary solutions due to budget constraints end up costing a lot more money than doing it right in the first place. I think I've mentioned my brakes before, but that's one good example. I probably spent more money and a ridiculous amount of time on the vacuum pump, and all of my attempts to get it to work right than it would have cost to just do hydroboost. I went with the vacuum setup because I didn't think I could spare the budget for hydroboost, but I should have just gone with the hydroboost to begin with.

Do you think this will hurt or help your mileage? Keep this going I am really enjoying this and best of luck with it. I happen to believe in torque over HP when it comes to a jeep. It seems to me a diesel makes more sense any way in a jeep for everything but racing. Well even with the new technoligies they have developed, such as Audi in the LeMans racing. It may make more sense for a jeep down the road for anything.
Craig
I would be extremely surprised if it doesn't help mileage considerably. It was wasting a lot of fuel waiting for the big turbo to spool up, and now it's just effortless.


i wonder if something like this could be done in a full size van. maybe with a hi/lo range manual transmission
I'm not sure if it would be able to push highway speeds. That has been where I've had my biggest challenge. It has no trouble accelerating or driving around town, but after about 45mph the Jeep's barn door aerodynamics start making it work a lot harder. The challenge has been to keep temps down with the fuel needed to maintain speed without having to wind it out to keep the turbo spooled. I pretty much have it dialed in now, but I'd be worried about it with a bigger and heavier vehicle that also has horrible aerodynamics. For one of those I'd probably lean towards the Cummins 4bt or Isuzu 4bd. A Cummins B3.3 may be another possibility, but they generally cost a lot more to acquire than any of the other engines. Then again, if it was a GM van, I'd probably just drop a 6.2 or 6.5 in it. They have their own problems, but they're well tested, and can be bought for a lot less money than even my Kubota!
 

Funrover

Expedition Leader
This is a sweet build! Having a 71 Mercedes 220D (2.2 Diesel) as a daily driver I really think this is great!
 

redveloce

Adventurer
I took it over Stevens Pass on HWY 2 this weekend.

It did pretty well, holding 50mph in 4th gear at about 2000RPM going up both sides without any EGT issues. I could push higher RPM, but it wouldn't pull 5th gear, which takes it down to about 1500RPM when you shift at the governor in 4th, so I just tried to keep it in the happy zone.

I have it limited to 16PSI boost, and have gone as high as 19, but I've noticed that there isn't much, if any, noticeable gain over 14psi. I suspect I'm running into exhaust flow restriction and offsetting the boost increase with drive pressure.

I originally plumbed the wastegates following the advice on a long topic from another forum. The big turbo wastegate is fed from the full pressure tubing between the small turbo and the intercooler, and the small turbo wastegate was fed from the charge tube between the turbos. The idea is that the small turbo will 'hand off' to the big turbo when the big turbo gets up to speed. That works fine for a high hp, high boost setup, but mine is relatively low boost, configured for efficiency. The engine doesn't flow enough for a complete handoff. The wastegate on the small turbo opens at 6.5 PSI, so I'd see a total of about 12lbs of boost when the big turbo reached that level and the small one started wasting. At that point the big turbo wasn't accelerating quickly enough and it would fall on its face and EGTs would start rising.

I disabled the wastegate line to the small turbo while I wait for a boost controller to arrive, which solved the issue with it falling on its face and climbing EGTs.

I think when the boost controller gets here I'll move the small turbo wastegate feed to the high pressure fitting, and set it somewhere around where I feel the engine choking. The idea is that it will hold that level and start bypassing more exhaust to the big turbo. I'm not sure if the big turbo will make enough to build the boost any higher than that, but it should at least increase efficiency by moving the load to the appropriate turbine.

It's a similar idea to the original setup, except that the small turbo will maintain the target boost instead of dropping off completely as soon as the big turbo comes up.
 

redveloce

Adventurer
On the way over we stopped at a place where we camp regularly during the summer and took the back way, which is an old logging road, out of the campsite. I wish I would have kept filming, because we got to chew through some relatively deep snow shortly after I stopped the camera. I usually use the GoPro app on my phone, but it was acting up and I couldn't tell if it was actually filming. The spot where I stopped is where we usually go if we need to send or receive text messages or calls while we're camping, as you can probably tell by my phone alerting right when I grab the camera.

 

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redveloce

Adventurer
Amazingly quiet little guy. Beautiful scenery too!
I wasn't sure how quiet it is was going to come through on the video. Quiet was on my list of 'musts' when I was planning the project, and I've put a lot of work into making sure it turned out that way! How am I supposed to sneak up on Bigfoot if it's loud? :D

Sent from my Nexus 7 using Tapatalk HD
 

redveloce

Adventurer
My second boost controller arrived yesterday, and I got it installed and set the small turbo to waste at around 14PSI. Cracking pressure will be a lot lower depending on back pressure, so it starts transitioning before that. HUGE difference! EGTs on the top end dropped by a few hundred more degrees and it revs much more easily. There must have been a lot of drive pressure! I was able to turn up the fuel, and it goes like an SOB now!

I'm not sure if I've turned it up too much or not, I'll have to do some tests to see how the EGTs go. It will hold or accelerate on any of the big hills on my commute, and I can't get EGT to touch 1000 degrees. The mountain pass I drive over to visit family is a completely different scale though, so I'll just have to see. It doesn't smoke at all when driving normally, taking off fast, or pulling hard. It will roll a bunch of black smoke though if I let it bog down well below the RPM where I should be driving, and floor it. It's not going anywhere when you do that, so it's not a common situation to get into. Handy for tailgaters though! :sombrero:
 

K2ZJ

Explorer
My second boost controller arrived yesterday, and I got it installed and set the small turbo to waste at around 14PSI. Cracking pressure will be a lot lower depending on back pressure, so it starts transitioning before that. HUGE difference! EGTs on the top end dropped by a few hundred more degrees and it revs much more easily. There must have been a lot of drive pressure! I was able to turn up the fuel, and it goes like an SOB now!

I'm not sure if I've turned it up too much or not, I'll have to do some tests to see how the EGTs go. It will hold or accelerate on any of the big hills on my commute, and I can't get EGT to touch 1000 degrees. The mountain pass I drive over to visit family is a completely different scale though, so I'll just have to see. It doesn't smoke at all when driving normally, taking off fast, or pulling hard. It will roll a bunch of black smoke though if I let it bog down well below the RPM where I should be driving, and floor it. It's not going anywhere when you do that, so it's not a common situation to get into. Handy for tailgaters though! :sombrero:
SWEET! Doughnut time!
 

redveloce

Adventurer
Here's a few videos from yesterday. Nothing too exciting, just more dash cam on my commute. The sunroof part of the soft top was open during all of these videos.

Noise comparison at about 45mph next to a Ferrari

This is a hill that I regularly use to test modifications. It's not fast, only about 35mph, but it's relatively long so I can load it up. Not testing anything in this video, just driving.

Just another 35mph part of my commute.

I'll try to get some videos of it driving from outside soon.
 

Ristin

New member
Wow, that little engine gets you down the road; looks quite peppy in the video. It's a little to quiet for my tastes and I don't hear any turbo whine. Just kidding, I love it! Awesome job,
 

Dan Grec

Expedition Leader
Pffft. That thing will never have enough power to move a Jeep ! :Wow1:

(Funny how we don't see comments from those people anymore.....)

Awesome, awesome build. An inspiration for those of us that dream of a diesel jeep.

-Dan
 
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