Making an XJ into a rally car?

[SeanP]

Those that know me know that I would love to drive rally sometime. Their is a series in CA and NV (CRS with two sanctioning bodies, Rally America and NASA). My dream is to run a turbo AWD like a WRX/EVO type rig. However, rules say you can't start with a turbo rig like that.

Some folks are building FWD honda's, VW's, etc and starting there. That would be great, but I don't have any interest in starting way down the learning curve with a rig that I won't have very long. Basically, it would be the equivelant to going back to 1998 with my XJ knowledge.

In looking at all the vehicles that folks "run what they brung" at these events, I thought "Why not an XJ?" :idea: I already know everything about these rigs. I know how to build a cage and strengthen the weak points of the unibody. Here's the pros:
Pro's
Torquey 4.0 with reliable AX-15.
Cheap to find a mid 90's two door 5SP with a lot of miles
Easy to regear to 4:10s which with 29-30" tires would be ideal at keeping the torque curve in the sweet spot.
I already know how to build a cage
When/If I move up to a WRX-type car, I can reuse the XJ chassis for a rock crawler or sell it for a JeepSpeed rig.

Con's
Solid axles front and rear would give up some stability.
Questionable brakes. (not sure what the rules allow for disc upgrades)
Weight, although a 2 Door stripped should be able to get to under 3000#.

Any thoughts on this? I know it sounds crazy, but I just don't want to have to relearn a new chassis for a year or two, only to move onto a turbo subaru.

[ponyracer1]

If it we me, I'd lower it a little, and get the biggest sway bars possible with some HUGE shocks. The biggest problem you'll run into is body lean(due to the high COG), by the way that dude with the honda is gonna kick your butt, FWD, high rpms all the time, low center of gravity (etc). I think you'd wind the crap out of a 4.0 trying to keep up with those high rpm motors.

[Weasel]

I think it's doable. Your going to have to watch the weight though, but the honda's and vw's can be that much lighter. Find a XJ with the full-time four wheeldrive. Drop it a few inches. You could run wheel spacers if you wanted more stance. I don't think the solid axles will be that big of a difference, ride might suffer but thats what shocks are for. Get some good ones, Walker, Fox, ect. Can you run air bumps?

You don't have to keep up with the honda's high rpm's, you just have to keep the speed. I'd look at/try 31's if they would fit, more sidewall, bigger contact patch. Sawybars would need to be upgraded, depending on how you want it to handle, but might want the rear bar to be stiffer then the front.

Brakes could be an issue, maybe another vacuum booster or hydro boost? What are the rules anyways?

[CRASH]

Just yesterday I was thinking to myself, "that SeanP needs another project." :D

[SeanP]

Just yesterday I was thinking to myself, "that SeanP needs another project." :D

:) Yep, that's me.

looking at the rules more closely. Different mods will bump you up classes. I think keeping the rear stiffer and making it under steer a bit would be preferable. I would rather have torque than HP, so the honda's don't scare me too much.

[MogifiedXJ]

Find on with the 242 tc that way you will have the option of full-time four wheel drive.

[Weasel]

having the rear stiffer will create oversteer, front stiffer will give you understeer.

What about an auto with one a brett's paddle shifters?

[zthang43]

I like it! What do the rules say about removing glass? If you can get rid of all your glass that would lower the COG of course. Can you chop the top like some people on here do? If you are going to build a cage anyway, that would help save some weight.

I've had the same thoughts myself; seems like a slightly lowered and stripped XJ would make a fun rally car, especially if your mods allowed you to stay in one of the lower classes to be competitive.

If you lock the rear; you will have all the oversteer you want, on command with a touch of the throttle. Sounds like you already know this though.

[Weasel]

I doubt you can chop the top but might be able to install speedglass or even better netting.

[SeanP]

having the rear stiffer will create oversteer, front stiffer will give you understeer.

What about an auto with one a brett's paddle shifters?

I always name them wrong, I want to be able to break the rear loose before the front.

I am pretty nearly sure that I want a manual tranny.

Gotta have a windshield. If I pull the glass, I gotta have nets in front. I really think with a stripped interior, I could be looking at 2850# or so. Plus my fat ass ;)

I will probably want to put a wrap bar in the rear and then find/make some stiffer sway bars.

242, I wonder how the viscous coupler would hold up. would be cool to play with the coupler and change the rate of engagement.

[themangeraaad]

Could you remove the rear glass and replace with lexan or something along those lines? That would cut the weight down a bit.. and more importantly lower the COG a bit. Lower it a couple inches, backspace the wheels a bit to get a wider stance. Whatever you do, I want to know how this turns out. I always wondered how a XJ would be rallying after I bombed around the cranberry bogs in my camry, then went Jeep and did it in the stock XJ and it did quite well.

[Weasel]

I always name them wrong, I want to be able to break the rear loose before the front. No your right, having the rear come around is oversteer. You can just the engine power to break the wheels loose and induce a power oversteer, but thats a little different then oversteer/understeer. Generaly if the front is stiffer you get understeer and if the rear is stiffer then you get oversteer. You can get a poly windshield. Speedglass would make me one but I would have to buy a glass one for them to form it over as they don't have a mold. That would be a good group deal to get some poly windshields made and split up the cost of the glass form. The rest of the glass should be able to be swapped with poly pretty easily.

[SeanP]

Can the jeep speed guys make use of poly windshields? If so, then that would make an interesting ploy for a group buy.

I am wondering if a set of poly bushings would be a good decision? Plus some sort of upgrade to the track bar mounts/rod ends. Plus steering.

Maybe what I really want to do is jeep speed, but I am more interested in turning, steering and braking skill than just balls-out high speed desert whoops. The plus of my plan is if I bail from rally or upgrade, I will have a chassis I can sell pretty easily and I won't have to acquire knowledge about a ricer car that i am not really interested in fielding long-term. Dangeroursly close to non-tech here, but this is the group to tell me if I am totally wacked.

[87manche]

the 242 doesn't have a viscous coupler in it.
You're thinking of the 249 that came in the grands
You could do a 249 though
http://www.4x4wire.com/jeep/tech/xfer/249-231/
just the opposite of that

[tealcherokee]

the 242 doesn't have a viscous coupler in it.
You're thinking of the 249 that came in the grands
You could do a 249 though
http://www.4x4wire.com/jeep/tech/xfer/249-231/
just the opposite of that

242 is a viscous coupler as well.

this is exactally what im doing, a turbo awd rally cherokee

PM or AIM me

[87manche]

I was under the understanding that the early ones had the equivalent of a gear driven differential inside.
But then I went here to try and find out
http://www.discountjeepparts.com/index.php/cPath/2880_87_565?osCsid=901a9fc55af83068b2e3508597ff92a 9
and they list a progressive coupler for grand cheros with the 242 from 99-04, but nothing for the XJ models.
Can somone that's taken one apart answer definitively?

[zthang43]

The 249 uses a viscous coupler, the XJ 242 uses planetary gears for the full time position, from what I understand.

Seems like the 242 would be the best choice for the rally car because you could still choose between 2wd, 4wd, and full time.

[tealcherokee]

The 249 uses a viscous coupler, the XJ 242 uses planetary gears for the full time position, from what I understand.

Seems like the 242 would be the best choice for the rally car because you could still choose between 2wd, 4wd, and full time.

aparently its a manual clutch, set up, not viscous, not planetary

but yes the 242 is better

[bamajeepjunkie]

what is the best site to find info about rally racing, sorry googled and got a buch of b.s. thanks

[saxj]

aparently its a manual clutch, set up, not viscous, not planetary

but yes the 242 is better

Teal,

I :worship: to your superior knowledge of performance tuning, but...

The NP242 uses planetary gears!
No viscuous couplings, no clutches.

[tealcherokee]

Teal,

I :worship: to your superior knowledge of performance tuning, but...

The NP242 uses planetary gears!
No viscuous couplings, no clutches.

I guess the article i read was mistake, i just looked some more, it is a planatary for full and part time, and an open diff for full time, i dont know for sure how its locked for part time or low, maybe that is the clutch they were refering to

[Ronbo]

Any thoughts on this?

Dave Turner Motorsports ( http://www.daveturnermotorsports.com/ )has plenty experience with the XJ in rally trim.


http://www.sportcompactcarweb.com/events/0206scc_laughlin/index.html

Third place results in the Open class. Notice the high powered cars his lowly little XJ dusted? Porsche 911, Volkswagen Golf GTI, RX-7, right on the asses of leading WRX and EVO's. No fawking Honda to be seen.... :)

[mellowvision]

in a way, seems like the cherokee is better suited for rally than crawling, at least in a stock configuration. stock it's practically a volvo wagon! :)

[drew and not u]

in a way, seems like the cherokee is better suited for rally than crawling, at least in a stock configuration. stock it's practically a volvo wagon! :)

BLASPHEMY!!!

[DrMoab]

Teal,

I :worship: to your superior knowledge of performance tuning, but...

The NP242 uses planetary gears!
No viscuous couplings, no clutches.
At least the three I have rebuilt haven't had Viscuous couplings or clutches

planetary all the way.

That being said. I have rebuilt three. They are not the worlds strongest.

[tealcherokee]

At least the three I have rebuilt haven't had Viscuous couplings or clutches

planetary all the way.

That being said. I have rebuilt three. They are not the worlds strongest.

ive rebuilt a few myself....none of which failed due to abuse, they just plain wore out.

[HogWash]

Ive herd and seen that if your going to have issues w/your sway-bar then you can put steering stablizers in place of your swaybar end links.
(from the engineer of OX)

[streetpirate]

Ive herd and seen that if your going to have issues w/your sway-bar then you can put steering stablizers in place of your swaybar end links.
(from the engineer of OX)



my brain kinked after reading this.

[Beej]

my brain kinked after reading this. It seems to be becoming more common. I've seen three different setups all involving short stabilizer 'shocks' used in place of the swaybar links. In all three cases though, it was to allow movement of the swaybar in fast-paced offroad usage. In a road-based cherokee, especially for racing, I would imagine the stock-style setup with a stronger anti-sway bar would be preferable to the shock setup...

[feerocknok]

I am wondering if a set of poly bushings would be a good decision?

Or aluminum bushings. They're the sh*t.

[BrettM]

I had my 2wd MJ out on a gravel road yesterday... so much fun.... i'd love to build it rally style...

[Power5]

If you are going to add a turbo, you are already changing your class. I would at least swap out the front for an Independent setup. This will also save you some weight. Could probably just use some Liberty parts and box the control arms for stength.

[jeeptree]

I'll sell you my 91 240sx. That would be an alsome rally car fun fast and rwd get a good tire, shocks, set up and cage it on the road you go. I would do a car if I was in your shoe's and mostly because of the low COG. But it would look cool as hell to see some one rally in a xj. You would be the only one I know of using an xj so the cool factor is there. and just to let you no I was in to the rice seen "imports" not to long ago I'm not saying I no it all but I do no what I'm talking about when it comes to that. when I wanted to get an good 4x4, I started looking at jeep I was sold and just like there is this alsome club "naxja" to help you with your jeep there is also countless clubs to help you with 240sx, and you can find out alot about 240s and just about any other car out there. but what do I know im just a newbee....


ps. your not totally wacked. just creative.

[MogifiedXJ]

Could probably just use some Liberty parts and box the control arms for stength.

Liberty parts on a real jeep.

Blasphemy...

:nono:

[Weasel]

It seems to be becoming more common. I've seen three different setups all involving short stabilizer 'shocks' used in place of the swaybar links. In all three cases though, it was to allow movement of the swaybar in fast-paced offroad usage. In a road-based cherokee, especially for racing, I would imagine the stock-style setup with a stronger anti-sway bar would be preferable to the shock setup...

I think anyone that uses this set-up doesn't know enough about vehicle dynamics to be touching anything. Sway-bars are used to tune the roll moments front and rear to help or reduce the over/understeer effect. They also help body roll, but they add spring rate to the system. A shock doesn't have any spring rate.

[Beej]

Sway-bars are used to tune the roll moments front and rear to help or reduce the over/understeer effect. They also help body roll, but they add spring rate to the system. A shock doesn't have any spring rate. I agree with everything there. How does that disprove what I have seen?