IXNAYXJ

I'm posting this response to a question that was raised in OEM Tech a while back, because, well it's no longer OEM. This is not intended to start a debate about if lowering a Jeep is an unforgivable sin. I built this Cherokee to take endurance road racing in the 24 Hours of LeMons series, mainly for fun and to see if it was possible. You can follow the team on our Facebook page if you're so inclined. I also have a big lifted Jeep, so don't running for your pitchforks and torches just yet.

Anyway, here is the question and my answers:

I played around with a variety of different options and came to this one mainly for simplicity reasons. Sort of by accident I got a extremely good handling set-up. You will have to add some lift to the rear springs to match the front. Going spring under will lower the rear between 5-6 inches, more than you can get out of the front. We added a Rubicon Express 2" add-a-leaf and it worked out perfectly, and stiffened up the rear end up quite a bit. Depending on what rear axle you have results will vary slightly because the thinker the axle tube OD, the lower the Jeep will sit. D35 and D44 and both pretty small diameter, 8.25 slightly larger, and the 8.8 we run is largest still (I think 3.25").

Just copy me, it works, it's easy, and it actually drives awesome. I don't mean to sound arrogant, it's just that I know beyond a shadow of a doubt this set up works flawlessly.

I think we cut just over a full coil out (maybe 1.5?), but I honestly can't remember. I do know we couldn't get the axle to droop enough with the steering attached to get the coil out, so we just cut 'em in place. Worked great and saved some work:




Couple things to keep in mind; use a cut-off wheel, not a torch. The heat will effect the metal and change the rate adversely. Also, we weigh in at ~2900 lbs. If you keep the full interior or have a bunch stereo gear, spare tire, etc in it, it will ride lower due to the heavier curb weight. All we really did was strip the easy stuff out of the interior, but I think we added that much weight back in with the cage:





You will not be able to go much lower than what we have because the oil pan will start to have clearance issues with the front axle, and you will run into steering geometry problems. Unless you want to notch and truss the front axle (it has been done), run adjustable control arms and custom steering, this is about as low as you can go. For 99% of people, it's not worth the time and effort, IMHO.

If what you're looking for is purely appearance, the steering and road manners might not matter as much, but we wanted the Jeep to handle and steer well above all other considerations. Lower does not automatically equal better handling. Where she sits now, there's very little body roll and it's very composed on the road and race track.

We're running the newish generic shocks that came with the Jeep when I bought it for $200 and stock sway bars too. New OME or Bilsteins are on the way before the next race, but I don't think they'll really make that much of a difference; one of my rear shocks came loose from the axle and I raced the last 2 hours that way without any noticable adverse handling traits. We're really probably only 2.5"-3" lower than stock.

The biggest challenge is relocating the rear spring perches/shock and sway bar mounts. We did it the wrong way that worked, but it kinda sketchy the first time. I would not reccommend this way; we just plasma torched off the stock mounts, flipped and reversed them and welded them back on. It worked, but it's not the ideal way.

When we went to the 8.8 we had to fab new ones. The 8.8 is sprung under on the Explorer donor, but the distance between the perches was wrong and there was no easy way to make them work due to shock angles and some other stuff. We cannibalized some Comanche MJ (sprung under to begin with) spring plates and fabbed up our mounts, then burned them onto the axle.

This really the only part that is tricky and requires a little welding/fab skill. Do some CAD (Cardboard Aided Design) mock-ups then build 'em. While you're there, you can also do a couple stiches where the axle tube meets the center section; 8.8's are notorious for spinning axle tubes, but for a street application, it's not at all necessary.

If you're looking to fill up the wheel well more than we have it, go to a 17" wheel with a decent sidewall aspect ratio and it should look "better," tuner style. Hope that helped, feel free to ask any more questions if you need clarification.

Here is a picture of how the rig looked on stock little 15" A/Ts:



Here it is with 245/50R16 Toyo Proxes4's at our first race at Thunderhill:



At Sears Point last spring (Infineon Raceway):





And at our last race at Buttonwillow:





We also have a bunch of in-car videos that you can see on our YouTube Channel that will give you an idea of the speeds we were reaching (up to about 105 mph) and how stable and quick our race XJ really is. Enjoy!

-Matt
Petty Cash Racing

P.S. Here's our 1st place trophy from the last race

bmrrwolfe

Thats awesome to see something different like this!
What motor/drivetrain mods did you do?
If you kept it a stockish 4.0 how does that do against the smaller competitors?

IXNAYXJ

We've dumped the cat, added a cheapo cherry-bomb muffler (there are actually noise restrictions at some tracks) and a side exit exhaust, and a cone type filter. Everything else is bone stock, 202k mile XJ. The 8.8 gave us 3.73 gears vs the 3.55 which made a pretty significant difference, and the LSD really helped in corners. Watch some of the videos I linked and you'll get a good idea about the power.

We're by no means the fastest rig out there, and about 65 mph the Jeep realizes it has the CoD of a large barn and kinda stops accelerating as hard. It's really in the corners and under braking (totally stock front brakes, stock Explorer rear discs) that we're picking up most of our time and positions. It's kinda hard to believe, but the proof's in the pudding.

Mainly, we're careful drivers and stay out of trouble. We ran over 800 miles last race, so just staying out there and putting down laps is more important than super fast lap times.

-Matt

prerunner1982

I read a thread about this Jeep and the race awhile back. Really enjoyed it. Glad to see someone else doing road course with a Jeep...

https://www.cherokeeforum.com/f59/sc...-series-34556/

OHHNOES

Thats awesome!!!! Not what I was expecting from the title Rock on

Irongrave

very well build i love the Chump car/ Lemons racing stuff

bravododger

Un freaking real. I dont know what to say. Wow comes to mind.

99xj2.5

Never thought I'd see an xj on the track but I like it!

99xj2.5

HA HA just saw your front emblem.......that's awesome

THENNING

well if your gonna do it you might as well do it right and that looks like what your doing so keep up to the good work....its always nice to see something different like this

Jeep Jeep

wow! i love it took alot of creativity and time now just bring home a title for cherokee forum!!!!!

Bustedknuckle

I've seen this entire thing almost word for word elsewhere, and you just joined like 2 weeks ago.............



red cup or your full of it.

IXNAYXJ

Are you serious? What is a red cup?

Yes, I just joined two weeks ago because I googled the team name and there was a reference here. And no, you haven't read this before...I spent an hour writing it, embedding the links and posting the photos this morning. Some of the same info and pictures can be found on NAXJA, where I've posted several threads about this, but I've never gone into any significant detail about what we did to the suspension. Wanna see a picture of me in the car as proof or something?

To those who've given props, thanks! We have a lot of fun with it.

-Matt

IXNAYXJ

Yeah, The Archer brothers raced 4-cylinder MJ's in the late 80's in SCCA Sport Truck, even won a couple championships. I mentioned notching the front axle in my original text, and that's exactly what they did to get the camber in the front axle and clear the oil pan of the 'Manches they raced. Tommy Archer later went on to become better known for racing Vipers (and winning a lot) in the 90's.

http://www.archerracing.com/history.htm

-Matt

SLPRJP

Sweet, I was thinking of doing this with my ZJ!