Not saying it was your fault. People aren't exactly worried about their paint jobs when their car is worth less than $500.

 

I was rattling around the search engines, looking for lowered, or, better yet, road racing XJ's and found this thread.
I am building a 4DR, 4WD 1987 XJ for Chumpcar racing. I am extatic that the same lowering mods that I thought that I would try on the Jeep, are what works so well on your XJ.
I am going to cut the entire roof off of the car, and run it as a speedster, or, in order to ceep from running the roof net, (DRAGGY), jiust cutting the roof from the rear hoop back, and leaving the rear of the car looking like a Commanche would with the tailgate off.
I am also toying with the idea of lowering the engine an inch, every little bit helps the C/G.
The NP 231 will be gone, requiring a longer driveshaft and I will go with a CV joint D/S.
Seeing as I REALLY don't want to try to troubleshoot the RENIX system in the middle of a race, I will take the HP hit, and put the intake from a 258 and a 500 CFM 2BBL on the intake side, and the 258 HEI dizzy on the ignition, and CHUCK the entire engine management computer.
THOUGHTS AND SUGGESTIONS ANYONE?? Brie

 

The coolest thing i have seen in a long time, makes me want to build one.

 

how do you like the Race shifter?
I met Rory awhile back and he sponsored me for a rock shifter and I love it
He's an awesome dude

 

I think you're waaaaaay over thinking things. Renix is supremely reliable, I wouldn't screw with it at all (in all my years of Jeeping, I've seen far more problems with carbs than Renix). I'd also keep looking for a 2WD one; even after you get rid of the -231, you'll have the D30 to deal with. The 2WD ones come with a simple and light weight beam axle running spindles (no unit bearing), and is vastly lighter than even an empty '30.

I also wouldn't totally cut the roof/windshield frame on the Jeep. These are endurance races; the more comfortable the driver is, the better he'll perform. Thus, a dry and non-wind buffetted driver will be faster enough to make up whatever time you'd gain in aerodynamics. These races also go on regardless of weather; being drenched through to your nomex undies in 80 mph winds at 3 a.m. is no fun at all. Take it from my experience, wipers and a heater is where it's at.

Good luck, our mostly stock XJ scares the crap out of a lot of "faster" sportscars. I'll probably end up doing a Chump Car event when they come back up my way, it'll be the battle of the XJs! Hope to see you there!

-Matt

 

I still haven't had a chance to get it on the track (we're in thrash mode prepping for our race next month), but the quality of his R/T prototype shifter is excellent. Should be a big advantage when we debut it at Sears Point.

 

Thanks for the advice on the 2WD beam front axle Matt, I thought that they would go with somw kind of independant front suspension on the 2WD's, and that would bring in the problem of the dreaded outside front wheel tuck, which really screws with the handeling. If I can go lighter, and KEEP a solid front axle, I'm all for it.
As for the roof, I have been thinking of leaving it on, from the rear hoop forward, and even welding sheet metal to the hoop, making the finished product look like a Commanche pickup, and having a smaller cockpit area to heat. I want to cut some of the roof to lower the rear C/G, more than pick up any improvement on aerodynamics. As to heat, I was thinking of putting a new heater core in the car, but in front of the driver, not the non-existant passenger seat. This way, he or she will be in the hot air stream as it exits the car from the wide open side and rear windows. There would be no fan, with it's resultant drag on the electrical system, the core would be fed ram air when the car was in motion.
I agree with you, it would be cool to race the two XJ's against each other. On the longer tracks, if we were close, when the two of us were driving, we could draft each other down the straights, more for fuel savings, than being able to outrun the E-30 BMW's. Brie

 

I just want to say that this is way too cool! The picture in your first post of you out in front of the Beemer is awesome.

I am now a "like"er on Facebook.

 

Thanks! We've got a race coming up at the end of March at Sears Point (Bay Area) so stay tuned.

 

That thing is awesome

 

Last week, Tee and I went to the local wrecking yard, and picked up a 2WD front axle out of an MJ, and we will put new ball joints and tie rod ends into it tomorrow, as well as either rebuild the brake calipers, OR go to Grand Cherokee front brakes. I read somewhere that they are a LOT better than the early XJ brakes, but then I also read that post 1996 XJ brakes are also better. Suggestions anyone? According to Chump Car rules, I can go to any non-Brembo type brakes, as long as they don't cost more than twice what the OEM parts did when new. If the 96 or later XJ front brakes are better,I would be inclined to go with them unless the Grand Cherokee brakes were WAAAY better, AND would fit inside the price window. Brie

 

I'm glad that you said what you did about the AW4 in your race Jeep Matt. One of the guys on the Chump Cars forum board was telling me that the AW4 would come apart like a grenade after a few races due to the lockup converter shedding shrapnal into the tranny as it started to come apart in 24 hours of WOT racing. He suggested that I find a 904 tranny out of a 79 or 80 Concorde to put into the XJ.
WHICH Fords came with the proper 8.8 rear axles? Are the MJ rear leafsprings any better than the XJ ones? Brie

 

Are you prepared to be surprised? We're running stock brakes...and they work great...and they last. We ran the pads that came on them for the first two races, and only just swapped them out before our last race. We'll run that set in the race coming up in a couple weeks. We can consistently out brake a lot of cars.

You could do the Grand Cherokee upgrade, but I don't think it would be worth it. They do make a slotted/drilled rotor replacement rotors for XJs which should be more then enough; I can lock all four tires up at 75...how much more brakes do you need?

 

Yeah, that guy's high. The AW4 is extremely reliable, never heard about the lockup TC being an issue. FWIW, for our next race we're running a tranny controller from RADesigns which will keep the TC from locking up at all. That's one of the nice things about the AW4 is it's electronically controlled, so you can tell it what to do fairly easily.

I also saw the comment on the Chump forum about the transmission being a Tremec T-5...NO it is not. In pre '90 XJ/MJs it is the HORRIBLE Peugeot BA-10, then in Post '90-'99 it's the pretty good AX-15, then from 2000+ the slightly better NV3550. Never been a T-5, WC or otherwise.

The Ford 8.8 axle you want is from a 199-2000 Ford Explorer of any type. To narrow that down, the ultimate is one equipped with a limited slip differential (Ford calls it Traction-Lock) and 4.10 gears. There's a tag on the housing explaining exactly what's in it:



Great info page where I found that:

http://www.therangerstation.com/tech_library/Axles.html

We're running 3.73 gears and a LSD, and it has made all the difference in the world over the D35. MAKE SURE YOU GET THE LIMITED SLIP.

MJ leafs will not work, the wheelbase dictates a much longer leaf pack which won't work for the XJ.

-Matt

 

Very cool!