Changing from a Crawler to Speed Runner - Coyote Install

[BanditBronco]

If you don't mind possibly gaining a small amount of height you can try adding some preload to the rear depending on where you are at currently to see if it stiffens it up just a tiny bit. Might make it feel more stable.

 

[68ford]

Rule of thumb is when at full droop, you want around 2 inches of preload. You probably are not under sprung but under valved. But neither of those affect sway. You need a sway bar like the Currie anti rock set up.

 

[Yeller]

You need a sway bar in the rear minimum. For street rigs with coil overs I really try to get them front and rear but it's not always package friendly. With decent link geometry the front isn't usually required.

 

[rcmbronc]

Rule of thumb is when at full droop, you want around 2 inches of preload. You probably are not under sprung but under valved. But neither of those affect sway. You need a sway bar like the Currie anti rock set up.

Do you think the Currie sway bar is big enough? I was going to put in a speedway bar but like some of the Currie stuff.

 

[68ford]

My buddy with a linked bronco just installed a Currie sway bar and he loves it. He wanted a sway bar that helped but was not so stiff that he had to disconnect it rock crawling. He said it's perfect. You need to make sure the arms around long enough for how much wheel travel you have. In a perfect world, the angle of the sway bar arms to link rods will be 90 degrees at ride height and the end link rods will be vertical above the axle. That is where it is the most affective.

 

[Yeller]

I've used curries successfully. I've played with heavier ones but they had side effects that weren't desirable.

 

[rcmbronc]

What was the side effects?

 

[rcmbronc]

Got the Currie sway bar mounted. It is better but still not the best. Still thinking I am a bit light in the rear spring department. I have 100 over 125. Probably going to bump that up a bit. I also have a bit of roll over steer in my 4 link calcs. Not sure if that effects it or really what I can do about it. Any ideas. It just seems to roll over a lot and then not real stable.

 

[rcmbronc]

Pictures

 

[Bukin 67]

I agree you're under sprung, especially for speed. Have you tried adjusting the Currie sway bar to help with the roll? I'm heavier, but I have mine (not Currie, but a rear set-up) set all the way to the stiffest setting, and my spring rate is about 3x yours.

 

[ntsqd]

The roll wouldn't and doesn't bother me. Then again I learned to drive in a Saab 96, and when going around a corner at speed those things heel over like a sailboat in a 40 knot wind.

The Roll-Steer is something entirely different. You could address it by clamping down on the suspension movement, but that is not the correct way to go about it. It is much harder to do, but the correct way is to change the geometry to get rid of or reduce the Roll-Steer to an acceptable level.
Then work on getting the spring rates & sway-bar spring rate right for the use & driver comfort.

If you just clamp down the movement then you've lost part of what you were trying to gain with linkage, and you've created a machine that could kill you should one of the sway-bar links break in the middle of a corner.

I'm pretty sure that's not what you want to hear.

Digger made a post a while back talking about why JK's have rear trac-bars instead of single or double converging linkage. I lost track of it before I fully digested what he was talking about, but I think its worth finding as I suspect that his comment(s) apply here.

 

[Yeller]

What was the side effects?

If they are really heavy they make the vehicle tippy off road as the chassis follows the rear axle on the ground. Ntsqd is correct the lean is not really an issue as long as it tracts predicably.

 

[pbwcr]

Rear Swaybars control the sway and induce oversteer. On my 96 Bronco I finally removed the rear sway bar and I sure liked the handling. Good shocks was all that it needed. That rig had 4 link 3 bypass air shocks and res shocks in each side. In my 72 I have a rear bar, but is it pretty light Speedway unit. The 72 design has res coilovers and has a 3 link. Both rigs were triangulated links. The 96 had Fox hydro bumps and the 72 has passive poly bumps. Don't buy Fox bumps! The 95 had strong limit straps and the 72 does not have straps so far.
My Jeep build has the stock do nothing rear sway bar and a custom front bar the equals what Curry sells when in the off road [position and very stiff like stock in the highway position.. For sure that rig in NOT a go fast like the others I have built.. It has nice safe under steer and is very stable on the highway with my light trailer.
So there you go - just another look on how it is done by me.

 

[rcmbronc]

Well changed the rear springs to 300/375. Alot better. Still not the best. Couple issues I think I need to address. First I think I have a bit of bumps steer up front I need to take care of. I think I can raise the track bar on the frame and fix it. I was running tie rod over and changed that back to the bottom link under and the top on top of the steering arm. Running heim links. No drop pitman arm and WH raised track bar bracket. Now I think I need to raise the driver side of the track bar or try to lower the passenger side to get better matching angles.

One real bad thing also is the front King coil spring sliders are not free and rubbing the threads quite bad. Did a search and this seems common. maybe try ADM sliders. Kings are crooked in the truck and just plain suck.

The big animal I think is the roll oversteer in the 4 link rear calcs. Last calcs has it at about 9 degrees so I assume that is causing most of the uneasy feeling while driving it. Now I need to see what it takes to get rid of that.

Rear spring rate seems pretty good, maybe a tad stiff but we will see.

 

[rcmbronc]

I need some help with some advice to get rid of the rear roll oversteer. Hear is my 4 link calc. I cant seem to figure out what I need to change to get rid of the over steer. I am assuming flatter lower links but dont want to drop the front mount and just moving the rear mount up and in front of the axle does not really help the numbers. The rear lower mount is where it is because that is as far back as I can move the rear axle with the 40" long lower arms. I may need to shorten or build new lowers. Front lower mounts are already a bit below the frame. It does help to lower the entire truck but not alot. Any ideas?

 

[rcmbronc]

Ok wanted to update this a bit. I have a thread in tech about the motor I am building but wanted to add the progress to this link.

Decided to build a 427 stroker motor for the truck. As all projects it has pretty much totally gotten out of hand. Here are the specs.

Dart block, Ohio crankshaft rotating assembly, JE forged pistons, H bean rods, forged crank. 10-1 compression. AFR 205 Renegade heads, Comp Cams solid roller with roller rockers and stud girdle. Edelbrock Super Victor EFI intake, Accufab throttle bdy. Still deciding on ECU, probably either Holley HP or MS3Pro. Probably 8 coil system. Mad Dog 1 3/4" headers.

Well while I was changing motors I decided I needed to take the body off and paint the frame and some other stuff. Getting close now to putting it back together. Still some more details to go over.

Looking at the transfer case. I will probably not be doing hard crawling. Thinking about changing to a Atlas but what about just updating the output shaft on the Dana 20 with a HD one from Wild Horses. Think it would be OK or just break other parts of the D20. Also need a new rear drive shaft. Should I keep 1310 or upgrade to ? Maybe 1350?

 

[Justafordguy]

Sounds like it's going to be a beast, can't wait to see how it turns out.

 

[ntsqd]

By the time you upgrade and/or replace all of the wear parts in a D20 you're well on your way to an Atlas. Don't have to buy it with crazy low range gearing. I went with 3:1 on mine. Should I need more, which I highly doubt, I'll go with a doubler instead of changing the ratio. With a 130" WB that's an easy choice for me, a std WB might think differently.

Speed & HP favors bigger drive-line parts. I'd say 1330 min.

 

[Bukin 67]

As ntsqd said it might be time to think about an atlas, but I upgraded all the gears in my D20 for about $1K (had a shop do it) and have been very satisfied. The D20 is a pretty bulletproof little t/c, and because it's short I get the extra travel (19" rear) because of the longer drive shaft length.
I would go 1350's with the torque that motor will put out.

 

[rcmbronc]

Getting the chassis put back together. Rear end in. Need to detail the front end and install.