• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Supercharged LS3 crammed into an XJ

Got the truck oil pan on this will give me quite a bit more clearance over the axle.
f860057472835854d77d7feb833eea9d.jpg


Now the real work begins. Disassembly!
 
76cc51c3ba3f151202ca53f89e97ab97.jpg

Off with the hood!

44dd998e0802e96c2a383235ba17273d.jpg

Bumper

1eaa8eb085b1368fc4886c540c1c4874.jpg

Front grill. The little radiator is a transmission cooler. It worked well for me and I will have some sort of transmission cooler for the new powertrain.

Draining all the fluids now will get back to work in a bit.
 
Out comes the old engine
Really no surprises here other than the difficulty in removing the transfer case shift linkage. To remove it I had to pull back the carpet in the drivers side cab.
ec4a4ce632a8a59cd5918078aa626087.jpg
 
361318dbf2ba630c8753f3eb2395f84d.jpg

70bffc36cbed77cb295895b30818dbc3.jpg

Definitely should have removed the motor mounts firsts. I just pulled the bolt that goes through the bushings in the motor mounts and had to fight them the whole way.
In the background you can see my WK2. That is a 2018 TrailHawk ecodiesel. The independent suspension doesn't flex very well but the air suspension and traction control is really really nice.
 
Last edited:
Over the next week or so I will work on installing the Novak motor mounts and integrating the wiring harnesses. I am still concerned about the intercooler fitment. Between the giant Novak radiator, the AC radiator, a transmission cooler, and a supercharger intercooler, and possibly an oil cooler I am gonna be real tight on room. I really don't want to mount any of the coolers outside of the grill but may be forced to. I also need to have the exhaust hooked up when the engine goes in. I kept the catalytic converters from the camero and will try to use them for this. Gonna be pricey!!$$ But at the end of the project having an XJ with somewhere around 600 horsepower will be pretty damn fun. Solves my towing problems for sure.
 
Looks like progress.

When it comes to towing, make sure you upgrade the brakes to match the pulling power. It would be a shame to send that engine back to the wrecking yard.
 
I'd skip the engine oil cooler myself. I don't think the exhaust manifolds are going to work out, either, but I don't have a set here to try. I have a set of CTS-V manifolds that I think might work. The Trailblazer ones didn't work. I think the Novak ones are a Vette driver side and possibly f-body passenger's. I really don't want to run headers on this.
 
I'd skip the engine oil cooler myself. I don't think the exhaust manifolds are going to work out, either, but I don't have a set here to try. I have a set of CTS-V manifolds that I think might work. The Trailblazer ones didn't work. I think the Novak ones are a Vette driver side and possibly f-body passenger's. I really don't want to run headers on this.


What about a transmission cooler? I can always add coolers later as needed. Also the headers on here are Novak’s, and they should slide right in.
 
Looks like progress.

When it comes to towing, make sure you upgrade the brakes to match the pulling power. It would be a shame to send that engine back to the wrecking yard.


I just put on a VANCO big brake kit last weekend. Made a world of difference, stops like a normal car for the first time in fifteen years.
 
What about a transmission cooler? I can always add coolers later as needed. Also the headers on here are Novak’s, and they should slide right in.


A trans cooler isn't a bad idea if you're stressing things out, but I'd honestly run without one and see how bad it really is. You can get the trans temp with a scanner. Engine oil temp, too.

I thought you were using the Camaro manifolds, my bad. No question the Novaks will work!
 
I am absolutely subbing to this. Awesome job so far. Thank you for sharing

Thanks man. I don't know how helpful it has been for people yet but think that as I get into the wiring, fitment, and plumbing some good lessons learned will become available to the community. I have learned so much from NAXJA and other forums that I couldn't have done this without the help and didn't want to waste an opportunity to contribute.
 
Easy day today. Took advantage of access to my drivers side upper control arm bushing and replaced it. Those things are a pain!
Also removed my transfer case from the Jeep engine so that I can rebuild it and replace the input shaft.
7553036ad0ee5163566d73654cb5d4cb.jpg

130ca683e63d95fc04674708e8aa9ec8.jpg

413299f3cb4fc8038cc821309ac61efc.jpg

828053567ea63646213d4e44dae5b303.jpg
 
Made a bit of proton the last few days. I had to rebuild my transfer case to put in the new input shaft to mate with the Chevy transmit. I had already cut down the output shaft on the transmission but was forced to also cut down the input sleeve by 9/16”. Without a wider adapter between the tcase and transmission there is no other way to do it.

I also started the process of integrating the GM systems into the XJ. The first part was the EVAP purge valve, I ended up Frankensteining the XJ’s LDP bracket and mounting the GM purge valve on it in the same location. On the camaro this valve was right next to the evap canister I hope that I don’t run into problems because of the distances involved. I worry that if it leak tests itself it may register a fail because of all the extra tubing.

0c75e50db4fc821468261c539d769f30.jpg

c25d727935a71c607ab6b68fb4550893.jpg

19257bd373c06b967960976989c113b3.jpg

0995fd4be20fc2e489dc232b6361666b.jpg

bf23930f7aabeefc0c0b979ca3a12cce.jpg

These photos showed up in the exact opposite order they were supposed to but you get the idea.

Next up:
Integrating the camaro gas pedal into the XJ. This will require some custom bracketry and will likely take me five times longer than it should.
 
Got the gas pedal installed. Several iterations of mounts were made. The piece in there now is rock solid, the pedal sits just right and has full range of motion. I bolted/glued
/waterproofed the block in place and am confident that this will last for the life of the vehicle.
c9ef486d74a7144bde6128c0b58b13e1.jpg

b8bc04fa21336960372bcef9350c3ed9.jpg

Next up the lokar shifter. This one is going to be a bear!
 
To mount the locker shifter I had to modify the stock shifter mount. I basically stripped it then welded an angled surface on it.


742ea81e750f6b131de228d80edfe8b2.jpg

7c9ab1ac70ec2b61dfd6c0db3f601eb3.jpg

dd5b519a0f86618593ec738843ee9094.jpg

83b69e247075218f9872b0ff4a840d79.jpg

1feb47c38dda5582735869d23912e2e4.jpg

4360954c73bfb3bd5ff1c402d5fe947f.jpg


From here I had to cut my ash tray on the console to make room for the upper cable mount. Then put it all in for a test.

c3e2cba109dcd705e461de363895ca90.jpg

e847b4b37be0207e8e95b1f22e7715b8.jpg

Great success. When the motor goes in I will rout the shifter cable, pull everything out waterproof all the holes, run the wiring for the tap shifter and put it back together.

Tomorrow will be motor mounts!
Making progress.
 
Last edited:
I ordered a shift boot for the shifter and will install that after the wiring.
Motor mounts went in easy peasy. Really nothing to report here, just bolt them in. These are from Novak.
1bc0627bf1d0c2514b6e3eadae427ab0.jpg
 
I labeled and pulled the wiring harness from the Jeep 4.0.
Next step will be stripping it down to the needed components. I will list them all as I get back to work on this part of the project. I will be out of town till the end of the month so there won’t be any progress till November.
3c45e866020dd72a548bb1c8e8baa623.jpg
 
Finally made some progress today. I didnt want the XJ check engine light to constantly be on and I needed a way to know if the GM check engine light was on sooo...
I pulled the gauge cluster and isolated the CEL light from the XJs circuit.

09ac451bdc56a844b8a9f6e2bdd8d39b.jpg

5c266ef1f7c3734d4c207fe10a5419a6.jpg


Then I soldered two wires to the back of the now isolated light bulb. These wires will connect to the GM CEL wires that were provided by Novak.

71611c21aa4e7eabfa66107e084cec12.jpg

Back into the gauge cluster it goes..


8303a97fe38136682863937d20a240c8.jpg



Below you can see that it lights up when 12V is provided. I just used a battery charger to supply the voltage for testing.


628329e70a4e58b6d37af6bfaf71e5d3.jpg

c99f2ca2abfae334d0da0d698019b346.jpg
 
Last edited:
The rest of this week I will strip the XJ engine harness and sort out the last of the things I can before the motor goes in this weekend. Mainly need to get the fuel lines sorted out along with the transmission fluid lines (I am going to put my trans temp sensor in the new transmission lines). I have no interest in pulling the motor back out to reach something that I have access to now!
 
Back
Top