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  #1  
Old June 1st, 2007, 21:22
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Prerunner type build-up

I have some serious back issues and can no longer handle hardcore wheeling, it is just to hard on this thrashed body of mine. I still will be wheeling some but the hardcore stuff will be limited. I also daily drive my XJ so ride quality and handling is a concern.

This has prompted my build-up to be a prerunner style. Here's the plan:

Skyjacker subframe with good control arms. 5.5" Deaver coils or 6" Skyjacker coils. (I won't run a swaybar so I need stiffer the front spring rates)

High quailty shocks that are valved for the weight and handling requirements.
Kings or something of the sort will be done in the near future.

D30 front axle, geared, fully trussed and reinforced. Tires for now will be 33x10.5-15's on lightwieght forged alloy rims. Oversized front rotors and calipers will also be used.

The frame will have stiffeners built from frt to rear and welded on. The rear axle will be a trussed D44, geared and locked. The rear shocks will mount to the leaf sping plates and extend into the rear compartment and mounted to a custom shock hoop. A rollcage is also planned on. Boomerang shackles and slightly longer rear springs will be used for correct shackle geometry.

My goal is to have a XJ that rides and handles well at speed, yet is still capable of some hardcore fun at times. This might wind up being the last build I can do on my own and I plan on doing it right. (I have a bunch of other things planned or already done)

BTW, this is for my '95 XJ with 75k miles on it and a fresh longblock with some mods. The '94 will become a parts XJ.

Any input would be great. Thanks
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  #2  
Old June 1st, 2007, 22:15
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Re: Prerunner type build-up

Just a thaught, and don't get me wrong.

If your body is too thrashed for 'hard core' wheelin'....

ya' think your body would like high speed running better?





Rick
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  #3  
Old June 1st, 2007, 23:10
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Re: Prerunner type build-up

I will like the ride that a properly setup prerunner suspension has to offer.

I never said I was planning on high speed offroad use. Some minamal amout of time will be spent blasting down fireroads and doing about the same amount of hardcore wheeling, if not less. Mainly trail runs with friends and the trip to Moab I have yet to experence. Other than that I will daily drive it like I stole it for the most part. I love playing in the snow also.

Like I stated before this will probably be the last real build I will be doing and I want it done right.

Thrashed = 10 degerenerated discs a 4 level neck fusion along with a few other issues.

If you still want know why I still plan on wheelin why read my signiture...

Last edited by TNT; June 1st, 2007 at 23:18.
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  #4  
Old June 2nd, 2007, 07:00
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Re: Prerunner type build-up

Quote:
Originally Posted by TNT

Thrashed = 10 degerenerated discs a 4 level neck fusion along with a few other issues.

If you still want know why I still plan on wheelin why read my signiture...

Sounds like your into that big slide already!!!

But, I know what you mean.

I'm thinking your best best bet is just searching and reading (as if you didn't know!) Spend the bucks for the 7100 Bilstiens and learn how to revalve them.
Buy the best seats you can get your paws on (I run PRP Daily Drivers.)
If you like the four-by stuff stay away from the fibre glass fenders...
Cage it.
Have fun with it.


As far as your back goes, the seats help the most. The shocks and your Deavers will help you out a bunch too.
Then get your old ass in gear and get started!!


Rick
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  #5  
Old June 6th, 2007, 01:27
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Re: Prerunner type build-up

I'm with Rick on your back and the really fast stuff. My back and neck handle trail running better than they handle hauling ass through the desert or dirt roads.........it's still fun, though.

My thoughts for what you're wanting to do are to go in the direction you're thinking, make it strong so it will last and be reliable, yet keep the spring and shock rates a little softer than what would be ideal for the fast stuff. I've found that as my spring and shock rates got to the point that it could handle the fast stuff better, it wasn't as comfy on the trails. If you want a balance between good handling, decent and comfortable performance on fast dirt roading, and comfortable trail running, use good parts but softer than you'd use on a true prerunner. I think the Deaver leaves are fairly soft, since desert rigs work best with soft rear springs, but consider a little softer coil for the front.

Use the Prothane coil spring inserts for your front bumpstops, they work great and are cheaper than air bumps. If you can afford them, air bumps would work best in the rear. Otherwise, use a competition style poly bumpstop, the ones with 3 or 4 gaps in them. I've tried all kinds of XJ/MJ rear bumpstops and none of them are cushy enough, or last very long. If you want to be able to go reasonably fast and be comfortable, get good bumpstops. It's the slamming down and bottoming out that gives you the hard jolt, if the rest of the suspension is set up well.
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  #6  
Old June 8th, 2007, 16:29
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Re: Prerunner type build-up

Quote:
Buy the best seats you can get your paws on (I run PRP Daily Drivers.)

With back and neck problems, this is the most important thing said yet. Dont be cheap here, by the very best seat you can possibly afford.

A prerunner is set totally different from a rock crawler. Go to Jeepspeed.com and check out some of them. Crawlers are set up best with a low COG, soft suspension, marginal compression and losts of droop. Prerunners are almost a complete opposite, they still try to get the lowest COG as they can but thier suspensions are setup more for a 50/50 (compression/droop).

I think (IMHO) that an XJ does faily well as prerunner, but an MJ would do better. Wheelbase is your friend at speed in the bumps, ruts, and whoops.
I would build a Waggy 44, mid or long-arm with Deaver progressive coils and Bilstien by-passes in front, and a 9-inch rear with 63" (Chevy) Deaver prerunner springs setup SUA, with Bilstiens and air bumps. Cage it, plate it, and run it!
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  #7  
Old June 9th, 2007, 21:35
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Re: Prerunner type build-up

It's going to be a trail rig for mild trails and daily driver use. It will see some hardcore trails sometimes and do some high speed runs at times. I don't plan on jumping it or running the hammers with it.

I know a good seat is a must. I was planning on bypass shocks. I already have the skyjacker subframe set-up and my rear springs/shackles. I was planning on the stiffer rate front springs because of my heavy front bumper that will have a winch. I also don't run swaybars and don't plan on ever using them again.

I have cut my fenders dramaticly so no fiberglass fender are needed. Suspension travel will 50/50 or have slightly more compression. Planned lift is about 5.5-6". Axles will be a trussed HP D30 front and a trussed D44 in the rear. I might raise the LCA mounts 1.5" and the UCA mounts 2" also. I'm trying to keep unsprung weight as low as possible. They will be regeared and the rear will run a detroit. I'm not sure what I'm going to do with the front axle for a locker since I plan on using my 242 transfer case.

Ride quality and handling are my main concerns.

Like I said already the frame will be reinforced and a cage will be added.

It will be built in stages as money permits. I have some other things planned for it too.

Thanks for your input, it's always welcome.
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  #8  
Old June 9th, 2007, 23:01
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Weasel Weasel is offline
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Re: Prerunner type build-up

If you want a good ride soften the spring rate like Goatman suggested. Firmer will take harder hits but transmit more to you, not what you want. Not sure why you are dropping crawling, it would seem that with a soft spring crawling would be beter then any type of go fast. Ever ridden in a go fast truck? Don't trying to be a dick but they don't have that smooth of a ride. Yeah it soft and does well for what it's hitting but not the best for a bad back.

And ditto on the seats.
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Old June 9th, 2007, 23:22
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Re: Prerunner type build-up

Quote:
Originally Posted by TNT
It's going to be a trail rig for mild trails and daily driver use. It will see some hardcore trails sometimes and do some high speed runs at times. I don't plan on jumping it or running the hammers with it.

I know a good seat is a must. I was planning on bypass shocks. I already have the skyjacker subframe set-up and my rear springs/shackles. I was planning on the stiffer rate front springs because of my heavy front bumper that will have a winch. I also don't run swaybars and don't plan on ever using them again.

I have cut my fenders dramaticly so no fiberglass fender are needed. Suspension travel will 50/50 or have slightly more compression. Planned lift is about 5.5-6". Axles will be a trussed HP D30 front and a trussed D44 in the rear. I might raise the LCA mounts 1.5" and the UCA mounts 2" also. I'm trying to keep unsprung weight as low as possible. They will be regeared and the rear will run a detroit. I'm not sure what I'm going to do with the front axle for a locker since I plan on using my 242 transfer case.

Ride quality and handling are my main concerns.

Like I said already the frame will be reinforced and a cage will be added.

It will be built in stages as money permits. I have some other things planned for it too.

Thanks for your input, it's always welcome.
Sounds like you have it pretty well figured out. Obviously, the bypass shocks will make a difference. I've never run the Deaver coils, but especially with the bypass shocks they should give you what you're after. Comparing it to mine (I also have a real heavy front bumper and winch), I think my coil rate is over 250, but under 300.......I have SJ 8" coils with one coil cut off. The Deaver 250/300 progressive rate coils and bypass shocks should give you a smoother ride than what I have, and yet better abilty to take big hits. I'm putting money into a buggy, so there's no bypass shocks in my future.

I would also like to run the Deaver rear springs, but they would have to be custom since my leaves are MJ length, 5" longer than XJ leaves.......and the same money issue applies. My front spring and shock rate are stiff enough that I don't need a sway bar, but until they got this stiff I did run a sway bar for street driving.

Sounds like a fun build..........keep us posted.
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Thanks to , Falken Tires, Bishop-Buehl Racing Engines, Ten Factory Axles, Brown Dog, Hooker Harness, BILSTEIN, Raceline Wheels, WARN, G&G Auto Repair/Off Road, Yukon Gear and Axle, Full Traction, Cal, Russ, James, and many, many others.
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  #10  
Old June 10th, 2007, 04:43
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Re: Prerunner type build-up

Quote:
Originally Posted by Weasel
If you want a good ride soften the spring rate like Goatman suggested. Firmer will take harder hits but transmit more to you, not what you want. Not sure why you are dropping crawling, it would seem that with a soft spring crawling would be beter then any type of go fast. Ever ridden in a go fast truck? Don't trying to be a dick but they don't have that smooth of a ride. Yeah it soft and does well for what it's hitting but not the best for a bad back.

And ditto on the seats.
I was running 170# springs and they were too soft. If I'm in a good seat with the stiffer spring rate and properly valved shocks I'm sure the ride will be fine. What hurts my back the most is the side to side movement caused by dropping a tire off a ledge or using a swaybar on the street. It's not the small bumps that hurt my back. As for going fast it will mainly be done on fireroad and such(which will be done rarely). It's not like I can go for a desert blast here in Wisconsin... When I make my trip out west for some wheeling I will be pushing the suspension harder. It will see more street time then anything else. Right now my suspenion sucks on wasboard type roads and anything that has larger bump or holes in it. Mainly this is caused by the shock valving and the control arm angles, both of which I'm correcting. As money permits I will also be adding some air bumpstops front and rear.

Here a weird comparison...
My SRT-4 ACR(Neon) I just sold ran 220# front springs and 180# rear springs. It had the Toyico 5-way adjustable struts and rode fine for me on the street. It also ran large front and rear swaybars but was balanced properly. There was still an issue when entering parking lots but you had to go slow because there was no ground clearance... It usually lifted a rear tire on any steep parking lot entrances.

I'm sure with the added weight of the XJ the stifffer springs with bypass shocks will have a better ride. A properly valved shock will still allow for a nice ride and with the increased spring rate it will balance out the suspensions handling charateristics. Remember I won't be using a swaybar.

My 94 runs stiffer springs which are fine but it's the swaybar that keeps the suspension from absorbing side to side impacts.

As for not crawling as much think about how it feels to slam the rock rails into a large rock or catching the rear bumper when dropping off a ledge. There is no suspension to absorb any of that type of impact. So I going to stay on the milder trails where this isn't as much of an issue.

Last edited by TNT; June 10th, 2007 at 04:51.
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  #11  
Old June 10th, 2007, 13:52
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Re: Prerunner type build-up

That makes sence. Actually a really padded and tight fitting seat would probably help out a ton. They literaly can lock your body to the seat so you won't move side to side. I would add a harness as well then.

Didn't think about the rock rails, ect but thats true. Guesss that were the "suspension" seat comes in.
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