So my wife is into biodiesel, and she wants to drive a diesel vehicle of some kind. Now, we're both disappointed about the current state of affairs in the US and how hard diesels are to come by. That, and everyone is always talking about doing diesel swaps into jeeps and just about every other car out there. It seems that you are limited to either tiny VW 1.9 TDI engines, which are expensive and underpowered, but will net you great mileage, or cummins 4bts, which are HUGE, heavy engines that require practically a new entire drivetrain, from the axles to the tranny. There isn't really an in between.

So, my wife loves land rover discoveries, which are very similar to P38 range rovers, which come with a BMW diesel in europe (and a manual tranny, but that's a rant for another day). Now, BMW is making the N57 diesel in newer X5s and 335ds. These engines are roughly the same size at the 4.0, weigh slighly less, just under 500 lbs, and have more than enough power for an XJ - 265 hp and 425 ft-lb. From the little research I've done, the BMW I6 engines all use the same bellhousing bolt pattern, so you could use the ZF S6-53 6 speed manual that was used in 2004-2006 X5s, or whatever auto you want.

That 6 speed was also used in the land rover LR3, so you have a transfer case. I don't know transfer case bolt patterns or input shafts, but the X5 does use the NV125 transfer case, so maybe some other transfer case that has a low range could be bolted up, or you could just use the fancy one from the LR3.

that just leaves the wiring - which I haven't done any research on, except that BMW diesels have very complex electronics. I have no idea what would need to be done there.

I'm not planning on doing this swap, but if someone was crazy enough, it could be done with enough time and money. I think it would be a perfect diesel engine for the XJ. Or you could just get a LR 200 TDI or 300 TDI. They require about as much wiring as a cummins 4bt.

Any thoughts on my little mental project jeep?

 

I like your style and you hit the nail "time and money" with enough anything is possible. My wife wanted a 4x4 SUV that got good gas mileage. After some research we settled on a jeep liberty CRD diesel. We found an 06 4x4 with 45000mi. and the full skid plate package on eBay in Houston for a good price, and holy crap I am impressed. I love that thing, the torque it has is amazing. Since getting it I have dreamed of swapping a CRD diesel into my XJ.

 

i imagine the CRD diesel is a better option - cheaper and already a jeep so the wiring would be easier, but they're so rare.

O yeah, the X5 with diesel gets 26 highway MPG and it weights just over 5000 lbs (!!!). It's slightly more aerodynamic than XJs, but since we weigh nearly an entire ton less, i bet highway MPG would be close to 30. that is radical.

 

The CRD isn't as rare as you might think. I work at a jeep dealer, and we have about 10 or 15 that come in on a regular basis. But those who get a hold of one don't let them go, which makes them harder to find. We looked for ours for about two weeks before we found it. 30 mpg is very tempting and if gas gets anymore expensive I may have to swap and start brewing some biodiesel.

 

There was also a Grand Cherokee that used the same CRD. '05 or thereabouts. I was disappointed, as I sell cars in New York, and we weren't allowed to have them because they wouldn't pass emissions.....

 

Someone posted a CL link on here (cant remember the title) of someone in Michigan(?) that does the BMW swap into XJ's.

Maybe someone can post it?

 

I think its rather stupid they put stricter emissions on diesel cars than anything else. Just to keep the market on gas cars they make less power and use more fuel

 

4bt