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My turbo XJ

B

blkbird95

NAXJA Forum User
Location
Plattsburgh
Hi guys,

Just wanted to share a project I did during october. The XJ is a 98 4.0 5 speed. Specs of the main parts are:

Aeromotive DFMU with E150 frame mount fuel pump
Crane HI-6 ignition with 2 bar map and timing control
(free) ebay m12 turbo T3/t4 .63, custom 90 degree outlet
(free) ebay tial style wastegate (I put in a real Tial spring and other mods)
Spearco water injection
AEM wide band gauge controller
Synapse Missing Link
Titlon electric oil pump

The turbo is mounted below the jeep, but remains higher than the crossmember. The Rock Krawler 3 link allows for the room on the passenger side for the turbo's cold side inlet and outlet. I will be building a skid to protect it, but for now I am just having fun with it. I use a Tilton pump to return the oil back to the pan.

Boost is almost instant, which is a rock steady 8 pounds. The jeep has 33's with 4.10s and lunch box lockers. When accelerating hard in 2nd gear @ around 3000 rpms the tires fight for traction on the street. Throttle response is excellent. The bov is from a 05 subaru legacy gt and works perfect.

I did this project just for the experience. My jeep had plenty of power before, but after getting the fuel and timing tuned in for the turbo, I must say that boost is addicting. I have around 200 miles on the setup with just minor bugs to work out.

As for dyno numbers or "real" tuning, not yet. There is still plenty that can be done before that, besides the nearest dyno to me is 1.5-2 hours away and all they could do is give me a power rating. My DFMU, Crane box, and wide band are my tuning tools (not to mention spark plugs and my butt). Please check out the pics on my photobucket page. Sorry if they are really large, once they are uploaded I don't know how to change the size.
http://s460.photobucket.com/albums/qq327/blkbird95/98XJ Turbo/
1027081512.jpg


Questions, comments, flames or what ever is welcomed. Thanks,
Brad
 
Looks pretty good man. Only thing to say: Loom up all those wires! :D
 
Yeah another turbo XJ that is all together different. Looks like we all have done things so differently. I love to see other XJ turbos. Yours looks like a great setup!!!

Nice work.

Get that thing on the dyno!
 
Timing is stock, I adjust the knob on the crane unit until the knock goes away. With that device how would you find that answer? I do not have a knock detector other than my ears.
As for wire looming, I will do that as soon as the tape will stick again. It is only 20-30 degrees right now. I don't have a heated garage (any more).

AFR in boost - I usually shoot for low 13s. With the Aeromotive piece a simple adjustment while driving under load and the AFR can be what ever I want it to be. I am gaining trust in the DFMU (I monitor its function with the fuel pressure gauge).

Thanks for the comments, it was a lot of work, but now it is a lot of fun!
 
You should get some ZJ discs on that 8.25 so you can stop a little quicker too!

Sick XJ man. Just steer clear of those water crossings!
 
You can hook it up to a scanner and run it and you can find the true timing. As for 13's in boost...I would put it in the 12.0 to 11.5 range. Did you step down a heat range or 2 on the plugs?
 
about the scanner, I thought of the same thing after I posted! Plugs are NGK and the electrode is shorter and 1 stage colder. Gap is set at 28. I used plugs that a boosted viper would run, as we use the same stock plug!

I am new to tuning and understand that running richer when FI isn't a problem as it will aid in cooling too. I'll try it at 12 or lower and see what happens. Richer sure won't hurt. Thanks for the help. I am also going to monitor the IAT like you have done and see if that is pegging. I had thought about moving it, just haven't gotten around to checking it.

As for water crossings, no problem. The turbo is sealed and the air filter is in the engine bay. But I won't go deep enough to get water inside the jeep as I have a mint interior in this jeep and would like to keep it that way. My previous 92 XJ was used for deep water explorering and the side effects aren't worth it.
Thanks,
Brad
 
With water crossings, it's not whether the turbo is sealed or not (aren't they all?) but the effects of cold water splashing on very hot components.
 
I read about this regarding STS systems. They showed a toyota truck flogging it in and out of water proving that it won't be a problem. If it does ever happen I would be amazed! I imagine the turbo would have to be glowing hot and then be completely submerged for a period of time. I don't plan on being in that situation! I did think about that when planning the build and considered it a non issue. Water in the turbo inlet was a bigger concern.
 
Water will make your exhaust housing crack due to the quick change of temperatures probably it won't make it crack the very first try but it will eventually...
 
Turbo housings are very durable and react well to temp changes due to the composition. I would be more worried about a log kicked up or a rock I suppose.
 
sweet set ups
 
Rubber bushing is in the frame mount, no real good picture for you to tell though, so here is the axle out of 92 almost ready to go into the 98.

0922081815b.jpg
 
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