$2010 Race Jeep Cherokee Build

Intercooler pipes are almost done. There are a few tight bends due to space and available materials but it should still flow way better then our old setup.

Dave working on making more space for the hot side pipes.

This car and its crew are freaking legends.

Talking them into $2013, amongst other items on the agenda

It was great hanging out with your guys. Glad you could come up and see the city.

Finally took some pictures of the hot side pipes.

Do you normally run an air filter?

Yes, since we relocated all the charge pipes and reclocked the turbo we had to redo the inlet pipe as well. Dave welded up a new one but it hasn’t been installed yet.

Vigo wrote: Do you normally run an air filter?

We've been known to not run an air filter...

We’ve been distracted with our projects but finally had time to pull the Turbo 4.0L. Jeep has been sitting since July because at the last autocross the wastegate never opened so we ran way more boost then we wanted to. Dave was driving and said it felt stupid fast right until it blew a cloud of white smoke out the exhaust and engine bay.

Engine is now on a stand till we decide what to do with it. We did remove the head and confirm that we blew a head gasket on #5 Cylinder. Fire ring was pushed about a ¼” into 2 coolant passages. It also looks like coolant pushed out the side which would have sprayed on the exhaust explaining the steam from the engine bay.

Head gasket was a Felpro HD we installed a few years ago. So far everything else looks ok but we are going to tear down the block and make sure.

I'm trying to get my poop in a group and get things done on my XJ project. I have a question on your front end though, did you just kinda go with it or did you take time and play with the geometry on a 4 link calculator to ply with roll center and anti dive and such.

We need updates, this is one of my all time favorite Challenge cars, not just for the car but for the team as well.

Insert gif of crowd with torches and pitchforks here

I’m not the suspension guy but we didn’t use any calculators. I think the main goal was to get more camber. We then cut some springs and got a rough idea of ride height. After that correct the control arm and track bar angles so they were close to stock and the lower arms were parallel with the ground and check caster. We cut and lowered the upper control arm mounts, extended the lower ones, and moved the track bar bracket over on the axle. Suspension pick up points on the Jeep are all stock and we could actually swap it to 4WD if we wanted. Then it was a matter of messing with the rear leafs and swaybar to try and get it more dialed in.

We haven’t’ really touched the jeep in months. The Stock 240+ mile 4.0L looks fine other than the head gasket. Since the engine was out we were going to put in a 4.7L stoker that Dave build back in 2005 and was pulled from his daily driver when the rust got too bad. Turns out that even though the engine has 50k miles the exhaust cam lob on cylinder #1 was wiped out and the crank end plat was about 1/8”. We tore down the engine but had trouble finding a 4.2 crank in good shape. All the remans have dried up. We did find one but after we got it was turned .040” and had a welded journal. We still were going to use it but didn’t get around to installing or check it out more for another month or 2. Turns out the thrust surface was machined too much and was out of spec by .010”. Long stock short we couldn’t return or warranty it but we found bearings that would work. Whatever.

So while we were dealing with the crank we notice that the stroker 4.0L block was cracked at the bottom of the bores. It’s not into water and cracked on a casting parting line. We could use another block but we planned to reuse the 4.0L rods with ARP bolts and forged .060 pistons. So junk crank is going into the junk block, with nice rod and pistons. It’s also getting new Comp Cam and the last thing we need to figure out is what we are doing for a cylinder head.

New engine is not budget friendly but we don’t plan on bringing the Jeep back to the Challenge. Of course the stock 240K mile engine is still kicking around if things ever change.

So...

What are my main hangups starting with a 4WD XJ?

And what would you do differently if you were to do it again? (Ignoring motor, i can make power in a few different ways)

In reply to Swank Force One:

If you are lowering a 4wd the diff might hit the engine. Not sure how much clearance there is. We were worried about the solid tube axle hitting the oil pan so we notched it then realized we had plenty of room to spare. You should still be able to replicate any changes to the control arm and track bar bracket mounts on the 4wd axle. All the suspension pick up points are still stock on the shell of our jeep.

With the 4wd front axle you can’t notch and bend it for obvious reasons but they do sell offset upper and lower ball joints to correct camber. I think you can install those and get about 2 degrees. Hopefully the wheel joints won’t mind.

Our shorts are too long and have an inch of travel. Shorter front ones from an 80’s Chevy Monte Carlo should fit better. Not sure what to do about the rear yet.

Only other thing I’d change is upgrading the fuel system. Stock pump can’t keep up right now. We have smashed the pressure regulator with a hammer to get more pressure then. 36 lbs injectors are still at 100% duty cycle so we then adjust boost till the AFR’s are less scary. Oh and if we run under ½ tank of fuel we get full cut when autocrossing.

i am really enjoying this thread, it inspired me to build a cherokee as a daily driver and rallycross car until i can get my fox mustang stage ready/ it belong to a friend that owns a tax office, he gave it to me with the understand that i had to fix it and use it [URL=http://s285.photobucket.com/user/tdrrally/media/20150118_141735_zpsgg6xacvf.jpg.html][/URL] it had been off the road for 7 years with a blown head gasket that lead to a complete rebuild
[URL=http://s285.photobucket.com/user/tdrrally/media/20150717_205713_zpsf6whlib7.jpg.html][/URL] its far from finished but it drives great and has cold air! [URL=http://s285.photobucket.com/user/tdrrally/media/20150717_205725_zpsqdvacm4h.jpg.html][/URL] new tyres shocks radiator and a pace setter header for a wj its 2.5l AMC power of 2wd fury

I just reread this thread, and I still want to replicate this build. The xjr seems like a great car to deliver pizzas in

Going back though the thread I noticed there were no pictures or results from the $2013 challenge. We placed 1st in the autocross and 3rd over all. Our best drag time was 12.98 @ 100mph.

Our electronic shifting setup took a little getting use to and our first run was 13.5 in 3rd gear only, lol. Next couple of runs we started in second which got us a couple 12.9's with a 1.8 60' but then it started raining before we could try first. We were also hoping we wouldn't need 4th because the drive would have to reach forward and flip a toggle switch mid pass. That would put the computer back into normal mode in hopes that it would instantly figure out what was going on in the middle of a drag pass and give us 4th gear. Turns out our gearing was less then ideal and were bounding off the rev limiter in third but never tried 4th. We also didn't have a tach but did rig up a shift light. Problem with the shift light was Megasquirt wanted an LED and all we had was a random red bulb. When it was time to shift the bulb would barely light up. Our drag passes are always a cluster berk

This is plain awesome. I drew up the idea of doing this with a Wrangler back in middle school. Is it bad though, that one of my favorite parts of the whole build is the endlink exhaust hanger?

I always hoped the Jeep would see an ongoing support effort to increase performance. Any new news?

4cylndrfury wrote: I always hoped the Jeep would see an ongoing support effort to increase performance. Any new news?

This! Is it still alive somewhere?

java230 wrote:

4cylndrfury wrote: I always hoped the Jeep would see an ongoing support effort to increase performance. Any new news?

This! Is it still alive somewhere?

Yup, what's the current status of this? the guy who runs 'Petty Cash Racing' with the LSx powered Lemons Cherokee mentioned it on the DFL podcast last week saying he knows you guys and the car, but not what it's doing now.

How have I never seen this thread before now?

Its currently parked in Jeff's driveway.

Back in 2014 we pulled the engine since the head gasket blew. Short block looks ok and has been stashed in the corner of the basement. Next to it is a 4.7L stoker Dave built back in college with a ported head with a mix of larger Chevy valves, Olds springs, and retainers from something else.

We were going to put that engine in until we noticed the crank end play was 1/2" when we went to pull the balancer. As we tore down that engine we also found that a few cam lobes were wiped. Engine only had 50K after the rebuild.

New plan was to clean up the block, get another 4.2L crank, recondition the rods with new bolts, and stab in a new cam. of course we hit another snag when we found out the bottom of the cylinders were cracked.

It doesn't look like the crack went into the coolant so we are going to ignore it for now. Rods cam back from the machine shop with new ARP bolts. They are polished stock 4.0L rods with forged pistons. I think compression was around 9.5:1.

Apparently reman 4.2L cranks are hard to find since everyone is building strokers. Scat makes a new crank but was having quality control issues at the time. We were able to track down a reman but its pretty terrible to the point where the vendor refunded my money. Its been turned .030/.030, one journal was welded, and when we went to install it the end play was .015 too much. Somehow our machine shop tracked down .030 over sized bearings that also were .010 over on the trust too. So the the terrible crank is in the cracked block.

This is currently were the project stands and we haven't touched it since 2015. We have all the parts except a head gasket set. With a weekends worth of work it could be up and going again but it wouldn't be challenge legal. Life has gotten in the way with weddings, kids, and racing Lemons.

Another reason the project stalled was we were promised some parts, machine work, and a few online articles from another site. We received a cam kit but after waiting around forever it looks like its never going to happen. That's why we started tossing together what we had.

Awesome recap!

Boo its in pieces

We get it though. Life has a nasty habit of interrupting one's automotive endeavors. Glad to hear its not dead, just comatose .

cool

I read about this on bangshift a few years back, and have re-visited it a few times since. Kudos for taking a top heavy brick and making it do things it never dreamed of. Excellent, just excellent.