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VW TDI into a 99 XJ

sweetjeep

NAXJA Forum User
Location
Massachusetts
Hey folks. Just wondering if there is any interest in a build I am working on.

I have a 99XJ that I have a VW TDI installed into. The project is far from complete, I am just wondering if there is any interest in people following my progress.

There is a TON accomplished but I am going to have to start begging for help soon.

Anyone curious?
 
I only have one right this moment. I'll try to figure out how to post pics in a moment.

For the rest of the story:

I am a Jeep guy from WAAY back. ;) I joined NAXJA in about 2002 but have been quiet for the last couple years as I haven't been driving my XJ waiting to do this swap. Sadly, it appears that I have forgotten a LOT.

Though I am also currently rebuilding a 51 M38 (military CJ3a).

As for the build...

Basically it's a 99 Xj with a 1.9 TDI out of a Jetta. I have been itching to do this for years and I was able to buy a partly finished project that happened to be identical to what I want to do. The hard work was already done. So I am going to strip out the XJ I bought and do a "better" job installing all the bits and pieces into my 99. The guy I bought the truck from did a pretty solid "first try" and I am beyond excited about what I got. Plus, I bought it for roughly the cost of parts.

That said the "old" truck runs and drives at this point. It's about 100hp but motivates reasonably well right now. My goal is 200 hp and that will generate about 400 ft/lbs which should emulate the 4.0 nicely.

The weight of the Cherokee and a Jetta is shockingly close so that's a non issue. Trans ratios are close enough so as to call it the same. The Cherokee trans ratios are actually a little better I feel. The Jetta is geared for an overweight underpowered car. I'll obviously be taking care of the underpowered bit.

I'll post pics as soon as I can. I have one with me, but it appears that I have to have them hosted externally, so I'll have to do that.
 
A v-dub TDI in an XJ? Sounds like a major project. Keep us up to date.
 
subscribed! This sounds pretty cool.
 
So, I'm confused. You found someone else attempting this swap that sold you the project?

Yes. Similar swaps are done (or at least attempted) all the time. I know of a couple Rangers, a Tacoma, a Liberty, I have seen some Wranglers of older vintage. But this is the first XJ/MJ I know of.

The guy lost his garage space and decided he needed a proper car "right now".
 
2.1 diesel to TDI.
http://www.naxja.org/forum/showthread.php?t=1058224

I think there's a company that is working on a TDI swap kit, but for the Wranglers. Not sure how different it would be for an XJ, but the more unusual a project is, the more interesting a lot of us will find it.

Cool! But I am not sure why you would do that. In Europe you can get diesel XJs all day long! :)

HPI is the company making a kit. They are not doing the Cherokee kit now/yet. They make a kit for YJs and TJs. There are some significant differences in mounting and they are currently unwilling to make an XJ kit. Trust me, I pushed as hard as I could. I intended to buy their adapters to make my setup work, but didn't have to at the last minute.

They also leave you to fend for yourself in regards to the electronics. In the YJ it isn't a big deal.
 
They also leave you to fend for yourself in regards to the electronics. In the YJ it isn't a big deal.
It's also not that big a deal on a 95 or earlier XJ, really... even a 96 wouldn't be too bad, assuming you live in a state that doesn't require plug-in OBD2 for emissions inpection, or use an OBD2 based TDI setup (were there any TDIs earlier than 96? I don't know much about VWs.)

The real complexity comes if you try and integrate a stock 97 and later interior + instrument cluster with the VW setup... wiring becomes somewhat confusing at that point

The 96 and earlier cluster is very easily interfaced to almost anything, the only gauge you'd really have an issue getting to work would be the tach, which on a 91-96 displays 30rpm per Hz of input signal (i.e. 1000rpm = 33.3Hz, 2000rpm = 66.7Hz, etc) which works out to 2 pulses per revolution of the crankshaft. So you could put two diametrically opposed magnets on the harmonic balancer and then use a reed switch, a logic voltage supply (not sure if the tach takes 12v or 5v pulse signal) and a resistor to feed the tach input on the cluster quite easily.

The rest of the gauges are simple - oil pressure and water temp have senders you can screw into any adapter, fuel/speedo are built into the trans and fuel tank so no worries about those.


Aside from the instruments, you pretty much have to run the starter, feed the computer power during start/run + run, and maybe wire up some stuff for the AC, power steering, and emissions. Aside from that there likely isn't much to do other than trim extra wires and junk out of the factory TDI harness.
 
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