Pre-runner type suspension stuff

[marcusguy]

Originally Posted by Paul S

I thought it was do to the fact that at the softer 'crawling' valving they were working much harder at higher speeds than the proper 'high speed' valving did.
I was only running 100psi, so Robert's comment on pressure could play into it too.
Paul

The rule is that the stiffer the valving, the more heat (you're taking what causes heat-internal friction of the piston and oil-and increasing it). When running fast through the desert, you are going to use almost all of your travel constantly, whether your valving is soft or hard. With softer valving I just hit my bumpstops harder. I know from experience that low pressure will cause more heat and fade, so I bet that was the problem.

[BrettM]

Originally Posted by CRASH

It's pretty simple, my camera is unable to download pics at the moment!

CRASH

CRASH, I have a 2 megapixel Olympus that does a good job, I'll bring it when I come over. PM me when you get an idea of what day is good for you, again I'll be back the 17th or 18th.

[Goatman]

Originally Posted by Jeff 98XJ WI

So enlighten me as to why many of the new mods and things you west coasters do are "top secret" No pictures allowed? You're not planning to market the custom stuff, so what's wrong with keeping others up to date on progress and the thought process behind your design? Perhaps you just don't want to deal with a million questions? I don't know. I like to see progress on a design and know why someone would do something the way they are. Maybe it's just me? Jeff

Want to see a pic of my URF prototype long arms?

new long arms

[CRASH]

The design has been slightly modified since that picture was taken........

CRASH

[Beezil]

Originally Posted by CRASH

The designed has been slightly modified since that picture was taken........

CRASH

"sorry, no cameras please"

[Goatman]

Well, I got my needed repairs finished...welded crack in front D44 diff housing, repaired crack and reinforced frame near UCA mount, increased bolt size in UCA frame mount, and repaired and reinforced the ripped apart rear shackle boxes. Also completed reworking the bumpstops and installing the new remote resevoir SAW big bore shocks. I put tie wraps around all the shock shafts and took it out for a spin, and went to my usual spot to flex it up and check for clearance.

Both front and back hit the stops when flexed, with enough tire clearance (no rubbing the 37's), and with an inch of shock left in the front and about an inch and a half left in the back. It definitely rides better than with the previous shocks (Pro Comp ES3000 front and Rancho RS9000 rear, set on 4), and stability at slow to moderate speeds was good, better than I had expected. Stability at freeway speeds could be a little better, if I was going to take a long drive I'd consider putting the sway bar on, but the ride was very good. I hit a number of residential intersections with very large dips at between 20-30 mph, and bottomed out both front and rear suspensions. I couldn't feel the front bottom out, but I could the back, and the overall ride was very nice.....not jaring or severe at all. The back did have a noticeable thunk as it bottomed out, but much better than it did with the Rancho's.

Checking out the tie wraps on the shock shafts showed that the front shocks had bottomed out, but the rear shocks had about an inch of travel left. From this limited first drive, I think the front shocks could use one step up in valving for both compression and rebound, and I'll add bumpstops to the shock shaft while they're apart. I think the rears could use one step up in rebound valving, but the compression could be good. I'll soften up the rear bumpstops a little more to use up some of that inch of compression travel that I have. Of course, I'll check everything out in some speed runs in the boonies to veryify these initial conclusions before I do anything. I had increased the pressure in the rear shocks to 200 psi before I put them on, and I'm going to increase the fronts from 150 to 200 psi before I do anything else.

Having fun,

[jjvande]

any updates? i love this thread.

[woody]

Originally Posted by jjvande

any updates? i love this thread.

Yes! a good "back from the dead" thread!

[Goatman]

Originally Posted by jjvande

any updates? i love this thread.

Well, I did just start another thread on rear suspension, but here's a little updating on my experience.

The front seems to be working fine. I've raised the lower bumpstops a little so now I just barely bottom the shocks on a hard hit. The upper bumpstop is an extended Daystar that I have shortened slightly and cross drilled holes to make it softer. It seems to be working fine since I can't really feel it bottom out. The shocks are still too soft (remote resevoir Big Bore SAW's) and they will get re-valved shortly. I also am still running the RE ZJ coils, and I have a set of Skyjacker coils that I am going to cut down slightly to provide the lift amount that I want, which will also stiffen them some. Since the front is close, I'm looking forward to the stiffer valving and the stiffer coil working out real well.

The rear is a different story. It felt decent initially, but the shocks were too soft, and the bumpstops compressed A LOT, but felt OK. It swayed more than I liked with the soft shock valving. I raised the bumpstops a little to keep the shocks from bottoming on real hard hits, but then the bumpstops hit hard. I have the Daystar extended XJ bumps (with some holes drilled into them to soften them up some), with the gap/strap on the bottom, and that bottom strap part cracked and broke. Then the shocks totally blew, and it started hitting hard on the stops. I had the shocks rebuilt (poor quality SAW, but they're not production shocks) and the valving stiffened up, and also slightly lowered the shock mounts. The bumpstops were shrotened by removing the bottom part that was broken. Now, with the stiffer valving, it rides better, the side to side stability is greatly improves, the shocks won't bottom out, and it hits the bumpstops sort of hard but bearable. The problem is that the rear end bucks, but I can still run it faster than I could before. If I can get the rear end to buck much less, I'll be able to run fast enough to have plenty of fun. Check out the other thread about rear suspension at speed.

[Goatman]

Oh, BTW, it works GREAT in the rocks. It's comfortable at a pretty good speed down a rocky trail.

[clayman]

I just bought a 94 xj 4 door auto 2wd and I am going to turn it into a pre runner. ive been reading alot about jeepspeed but i really dont like all the limitations in the rules.

here is what i want to do this summer (if i can afford it otherwise it may take 2 summers)...


1) Bumper to bumper roll cage with pre runner bumper and something on the outside of the back to mount a 33.

2) fiberglass in front and a bit of hammering welding and bending so I can fit 33s

3) completly cut the rear appart, even the door if i need. this will be done when building my roll cage so i can reinforce the unibody from all the cutting. since there will now be a large hole going into the back of my jeep i am going to build aluminum fender for the inside so mud and rocks and dust dont go flying into the rear of my vehicle. I want to fit 33s without a lift so my center of gravity is still low.

4) also when building my roll cage im going to build a shock hoop for the rear that ties into the cage

5) i will hopefully get 17" 9100 2.5in quad bypasses in the rear unless a friend comes through i will get 16" king 3.0 tripple bypass (for $500, he could be full of crap though)

6) i want to get 4" devers for the rear to pull that 17" of travel and also give me a bit more up travel.

7) for the front i am going to extend the 4 link so i pull about 22" of travel. im going to tie in the upper mount somewhere to my engine cage.

8) i hope to get 22" coilovers for the front

9) bumpstops

10) race seats and harnesses

11) ford 9" for the rear

ok now i have a few questions. what do i do about stearing? pulling that much travel am i going to have to make custom stearing or does someone make something like that?

what is the best way to strengthen the front axle?


i already put in M.O.R.E motor mounts and a M.O.R.E tranny mount.

am i going to need a SYE in the back with that much travel?

any other things i totally missed. there must be other things i need to do for safety and strengthening my vehicle.

thanks for the help

[David Taylor]

22" front coils? If you used all that shock the front axle would be half under the car at full droop. You would need really long front arms. The rest sounds good.

[prerunnerXJ]

have fun pulling 22" of travel with barely any lift

[Goatman]

Originally Posted by clayman

I just bought a 94 xj 4 door auto 2wd and I am going to turn it into a pre runner. ive been reading alot about jeepspeed but i really dont like all the limitations in the rules.

2) fiberglass in front and a bit of hammering welding and bending so I can fit 33s

3) I want to fit 33s without a lift so my center of gravity is still low.

6) i want to get 4" devers for the rear to pull that 17" of travel and also give me a bit more up travel.

7) for the front i am going to extend the 4 link so i pull about 22" of travel. im going to tie in the upper mount somewhere to my engine cage.

8) i hope to get 22" coilovers for the front

ok now i have a few questions. what do i do about stearing? pulling that much travel am i going to have to make custom stearing or does someone make something like that?

am i going to need a SYE in the back with that much travel?

any other things i totally missed. there must be other things i need to do for safety and strengthening my vehicle.

thanks for the help

You said you want to fit 33's without a lift, and you're going to get 4" lift rear springs, and want to run 22" coilovers in the front.............that info doesn't jive, bro. Get some more realistic design perameters. Like Dave said, 22" of travel in the front is a TON, and I don't know how you'd do it.

Yes, you'll need an SYE in the rear.

You'll need a custom steering link setup, probably something with an idler arm, to handle even close to the amount of front travel that you're after.

[CRASH]

Originally Posted by clayman

I just bought a 94 xj 4 door auto 2wd and I am going to turn it into a pre runner. ive been reading alot about jeepspeed but i really dont like all the limitations in the rules.

here is what i want to do this summer (if i can afford it otherwise it may take 2 summers)...


1) Bumper to bumper roll cage with pre runner bumper and something on the outside of the back to mount a 33.

2) fiberglass in front and a bit of hammering welding and bending so I can fit 33s

3) completly cut the rear appart, even the door if i need. this will be done when building my roll cage so i can reinforce the unibody from all the cutting. since there will now be a large hole going into the back of my jeep i am going to build aluminum fender for the inside so mud and rocks and dust dont go flying into the rear of my vehicle. I want to fit 33s without a lift so my center of gravity is still low.

4) also when building my roll cage im going to build a shock hoop for the rear that ties into the cage

5) i will hopefully get 17" 9100 2.5in quad bypasses in the rear unless a friend comes through i will get 16" king 3.0 tripple bypass (for $500, he could be full of crap though)

6) i want to get 4" devers for the rear to pull that 17" of travel and also give me a bit more up travel.

7) for the front i am going to extend the 4 link so i pull about 22" of travel. im going to tie in the upper mount somewhere to my engine cage.

8) i hope to get 22" coilovers for the front

9) bumpstops

10) race seats and harnesses

11) ford 9" for the rear

ok now i have a few questions. what do i do about stearing? pulling that much travel am i going to have to make custom stearing or does someone make something like that?

what is the best way to strengthen the front axle?


i already put in M.O.R.E motor mounts and a M.O.R.E tranny mount.

am i going to need a SYE in the back with that much travel?

any other things i totally missed. there must be other things i need to do for safety and strengthening my vehicle.

thanks for the help

Your plan seems realistic and well thought out. Good luck.

CRASH