Exhaust Gas Recirculator - basically pumps some exhaust back into your intake charge - supposed to lower combustion temps which lowers NOx emissions. Gas engines have had them for a while. They are becoming more popular to control diesel emissions now too (though GM had them on the old 6.2 many years ago).
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Diesel XJ - I'm all searched out!
- Thread starter Spaz_Soldier
- Start date
Exhaust Gas Recirculator - basically pumps some exhaust back into your intake charge - supposed to lower combustion temps which lowers NOx emissions. Gas engines have had them for a while. They are becoming more popular to control diesel emissions now too (though GM had them on the old 6.2 many years ago).
As an aside, do you happen to have links to the conversion on either your SJ or that guy's ZJ? I'm squirreling away ideas for a future swap.
Lost my old photobucket account that had all the pics. Need to repost them again.
ZJ swap was somewhere up here - http://www.thedieselpageforums.com/tdpforum/
Spaz_Soldier
NAXJA Forum User
- Location
- Winchester, VA
That sounds like a stupid idea...
raisersedge
NAXJA Forum User
- Location
- oregon
I would go with a vw tdi. With nozzles and a good burn on the computer. You should be able to pull 170 hp and close to 300 torque that should run with the 4.0. It should not be hard to build an adapter plate and motor mounts. When you get the computer done you can also have the immobilizer removed and the wiring harness cleaned up. The motor and essentials should run you around $2500. I have seen whole running driving cars go for $3500. We installed one in a toyota extra cab on 33s with 4.10 gears. Which seemed to be a good rpm range. We averaged low to mid 30s for a mpg. Ar that truck is easily 1000 lbs heavier than a cherokee you should get even better mileage. The power was every bit of what the v6 we took out. It did not struggle up the hills like the v6 did. If you dont have any experience with the TDI I woul;d look at before you say it is to small and to weak. The other good thing is that with a TDI you would lose 150 lbs and alot smaller engine more room for other mods.
jcshaney
NAXJA Forum User
- Location
- portland IN
There is a Canadian company doing tdi swaps for yj's and they are working on one for a tj. As of right now all they adapt to is a ax 5. May be you could hit them up for a adapter plate and info for the electronics there sit says some thing about flash to 187 hp and 287 for tq and eliminating the immobilizer
http://www.hpamotorsports.com/tdijeep.htm - are these the folks you're thinking of?
Personally, I'm not completely convinced that the TDi is necessarily the best choice: my main concern is that given its relatively low displacement the turbo's going to be seeing a lot of runtime, and in an engine that has been modified to put out substantially more power than stock this could be problematic.
Then again, I'm not terribly familiar with the TDi, so could be off on this. Part of what has me thinking this way is that I've yet to see solid figures regarding its performance characteristics in the sorts of vehicles we're talking about here, so numbers and experiences would go a long way to alleviate that.
raisersedge
NAXJA Forum User
- Location
- oregon
I ahve had several some fairly built bigger turbos nazzles burns you name it. They all lived past 250000 miles some boosting and sustaining in the high teens. The cars weigh more than a cherokee and flat get it. Makes a ricer look stupid. I have put one in a toyota pick up and have seen them in others. Go to tdiclub.com and look at their conversions. I think a lot better swap than anything else on the market.
Goat
NAXJA Forum User
- Location
- Merrimack, NH
This is what a 4BT in an '89 looks like.
zluster
NAXJA Forum User
- Location
- Colorado Baby!
Have you ever driven a KJ CRD? Mine SPANKS THE PISS out of my XJ. Everytime I get back into the XJ I go, "man this thing sure is slow". The power may be lower, but you would never know it driving the CRD, the CRD just about never downshifts while driving in the hills, and will cruise up I70 in the colorado rockies at basically a high idle doing 75-80mph, my XJ struggles to go up the same passes at 60mph.
My CRD KJ has 245/75/16 tires with 3.73's.
My XJ has 245/70/16 tires with 3.55's.
The KJ CRD motor is also very tall! Requires shoving the motor WAY back against the firewall and pushing the front axle forward some to clear the oil pan. Even then a custom modded oil pan would be preferable.
For the record the same oil pan problems arise when trying to use a US CRD engine in a new JK.
I got my complete rolled CRD limited for my XJ swap for less than 4 grand, I sold off a butt-ton of stuff and now I'm at the figure of less than 3K for the parts vehicle right now.
this parts CRD sold for $850 in denver yesterday:
http://auc2.traauctions.com/kws/napplications/display_pics.aspx?Stockid=977238&Exit=Close
The CCV coats the inside of the turbo hoses with oil, causes them to soften, and blow, very common and a poor design from the factory. Jeep now has a newer redsigned hose that has a fluro liner for the passenger side hose. Several years ago I worked with Samco to develope a superior aftermarket hose that would not fail, I still have the original prototype hoses on my KJ and they are doing quite well after 70k miles.
Adding a proper CCV system like a provent or EHM will clean up those issue, you should see how clean my intake is after running like that for the past 70k.
Additionally the EGR puts out so much soot into the system(in an attempt to fight the big bad boogyman NOx) that disabling the EGR by unplugging the MAF is a REALLY good idea. Doing this keeps the intake path clean and the MAP sensor clean as well, I have come across WAY too many CRD's that have been serviced by inept dealer techs who diagnosed blown turbos simply because the MAP sensor was so dirty the Jeep didn't know what to boost too!
yup, lost is a great place, say hi next time your on, I go by SirSam over there.
Yes it is, but works to reduce NOx emissions. I could go on a long diatribe about emissions controls and compromising all sorts of other things, but as a calibration engineer it works to get it to pass emissions)
You can make the 2.8 CRD work with a manual trans, but its a little bit of trouble, I would recommend sticking in the complete 2.8, 545RFE, and NP242(or 231 if you want they interchange easy).
The wiring is not THAT bad once you get it sorted out, but I spent many an hour working through it all, but basically you strip down the KJ harness to the main connector plugs, interface them to the XJ harness, and then tie into the PCI bus for all your other stuff.
Mine has been an ongoing project, its been put on hold for about 1.5 years now while I finished school and am flipping jeeps untill I find a job(can't afford to work on the MJ, need to work on vehicles I can sell to make a profit).
And I know you've already seen it, but for the record here is my Mj build thread:
http://www.naxja.org/forum/showthread.php?t=955062&highlight=project+crd+mj+born
Yes, I have.
*Shrug* maybe it was the KJ I drove (press car), but the best way I could describe the way it felt to me was that it was not as quick off the line as a 4.0 XJ but better on inclines. This I attributed to its weight over an XJ; if you re-read what I said initially, you'll note that I expected the XJ's advantage in that area to help in this regard.
This is the same size I'm running on my XJ, but with 4.10s. I'd say there's a point to be made that this is likely factor in your hill performance in the XJ, but will concede that it will only go so far.
Out of curiosity, is this at stock height or lifted?
So, wait - the KJ's ECU and sensors can drive the XJ's gauges, etc.? If so, that's pretty damned useful.
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Ya, but it has leafs and the shackles are at the wrong end. I'd want to keep the coils.
Please keep us updated on progress though.
zluster
NAXJA Forum User
- Location
- Colorado Baby!
when you touch the gas from a stop the low end torque of the 4L is apparent.
Then 1.5 seconds later when the CRD has fully spooled(thanks to the VGT turbo), the OMG this thing is so freakin fun I'm gonna get a ticket moment kicks in. One of my other vehicles is a 1993 Nissan 300zx Twin turbo with downpipes test pipes a catback and 4.10's. The VGT turbo in the KJ makes it a fair bit quicker off the line than the 300zx. It may not have the same HP, but getting the torque full makes the KJ a good deal quicker.
Even compared to XJ's running 225/70 tires with 3.55's the CRD spanks them with a large margin of spankness.
Both are at stock height.
NO. But they should be able to drive the PCI gauge cluster found in the later TJ's, which is a XJ clone and will bolt in. When you extract the CRD wiring harness to the engine side everything you need to connect to the body goes through 3 plugs. Rip out the XJ EFI stuff and combine. Seems complicated, and it is, but when you start spending some time looking at the wiring diagrams it actually falls into place nicely.
On the XJ the CCD bus is used to carry all the data for the cluster, the same thing happens in the KJ but uses the PCI bus. Therefor you need to use a PCI bus gauge cluster to work with the stock ECU.
There are a few other things - drive by wire(aka the APPS ) just needs to be mounted and wires routed to the plug. My application uses the APPS from a 1997-2001 2.5 TD XJ, this will work with my setup in the MJ since that is using the bosch EDC15 ECU, the 2005+ uses the EDC16 and needs a different APPS(actually one commonly found in other vehicles besides the KJ, ford toyota etc).
The sentry key(if equipped) either needs to be disabled with a new ECU calibration or the transponder needs to be mounted somewhere with a correctly programmed sentry key mounted nearby. The BCM verifies the signal and then transmits an "OK" signal to the ECU via the PCI bus. There are a couple of other functions that are necessary to keep the BCM tied into the PCI bus.
It's complex, at least until you sit down and figure it out chunk by chunk, then it doesn't seem so bad. There are lots of wiring diagrams I made for my reference during my conversion in that build thread, they should give you an inkling of the wiring needed.
Goat
NAXJA Forum User
- Location
- Merrimack, NH
With that much weight up front I wouldn't do a shackle reverse.
I think that engine is lighter than the 4.0...
Did a reversal (correction actually) to my SJ with that big heavy 6.5. Not sure why you think that is bad...
Goat
NAXJA Forum User
- Location
- Merrimack, NH
I don't know about that...dry weight of a long block 4bt is 705lbs, per the factory.
Oops, my bad. Was still thinking CRD.
Actually, that's not totally out of line with my observations. I'm also willing to admit that I was driving a press car, so it was a case of 'one careful owner, ten thousand careless drivers'. That's not to say that it was a dog or undermaintained by any means, but press cars (in my experience) are typically treated as badly as or worse than rental cars by the drivers. End result: this one may not have been typical of CRD KJs.
On the boil, it was pretty good up to around 75mph, at which point it started feeling a little breathless; by 85mph it was noticeably starting to run out of top end, though there was still some in reserve. I put that down to being a standard diesel trait, and in real-world driving (where the XJ rarely goes over 70-75mph) a non-issue. Off the turbo, there was enough pull that start-stop traffic wasn't a big deal and I wasn't noticing whiplash from it coming on at the wrong time in that situation. Overall its flexibility impressed me - particularly on long hills.
This is the standpoint I was making my comparison from; hopefully that clears up why I was looking at it the way I was.
Good to know. Any clearance issues between the engine and firewall with having had to move the engine back? Also, how much of a pain was it to get the 545RFE lined up?
OK, gotcha. So basically it's only using part of the existing wiring harness for transport; you still need the KJ's PCM and TJ instruments and the XJ PCM is basically removed. Understood now (which is what I thought the case was; just wanted to be sure).
Are there any systems outside of just gauges and engine management that are PCM-controlled on the XJ that you've been able (or not) to make work with the KJ's PCM? If I end up doing this, I'm going for 100% functionality, right down to things like the overhead console.
Cool. I had been wondering about this; thanks for clearing that up.
Hm. Hadn't thought of that, but you're right. Would there be anything preventing the KJ PCM from reading the SKIM module? I'm not familiar with the later security systems, so am asking this from a position of zero knowledge.
It really doesn't seem all that horrible when boiled down like this, though the wiring still seems like the big PITA. I'm almost wondering (now that CRD KJs are turning up at insurance auctions) if doing a commercially-produced harness and engine and transmission mounts might not be a bad thing to investigate.
zluster
NAXJA Forum User
- Location
- Colorado Baby!
I still feel like the CRd has plenty of balls from 80-90, keep in mind that drag is exponential the difference between 50 and 60 is nothing like the difference from 80-90.
I've had my CRD up to about 116mph, the last 6 MPH it just barely crawls up there, just too blocky of a vehicle for that much windspeed.
Yes all sorts of issues, I had to persuade the firewall to give it a little bit of clearance to make sure the engine didn't shake or rub.
I guess I don't have a good picture of it, but the rear lip of the firewall was cut in about a 2" section, and then some hammertime occured to make sure we were clear enough for the back of the intake manifold. I also kept the engine as high as I could but still clear the hood.
I am not using the 545rfe, rather I am using a NV3550, the MJ engine is a 2.5 CRD with a 5 speed(2002-2004 KJs are setup this way) the 2002-2004 autos have the 2.8. I would see no problem putting in the 545rfe, there is plenty of space in the tranny tunnel.
This pic kinda shows the firewal clearancing:
Nope, removing the XJ PCM doesn't matter, luckily for us the XJ is an old enough of a design it never used a BCM, if it did this would be somewhat more complicated.
My intention is the same, I want 100% stock functionality, the overhead console is a tricky one, basically your going to have to shove the KJ overhead console guts into the XJ overhead console, just no way that the XJ CCD trip computer will work with the KJ PCI bus.
As far as I can tell the BCM reads the skim module and transmits an OK message on the PCI bus to the bosch ECU. Basically you need to have the KJ BCM hooked up for the SKIM to let the ecu run. the BCM is also needed for the vehicle speed information to be read from the sensor and transmitted on the PCI bus to both the ECU and the guage cluster.
