shocks

I think I've finally decided to bite the bullet and upgrade my shocks. Tired of fighting the tire shake. The rear suspension is just plain wrong. I've known this since I bought the car but have been putting it off. now I have the funds finally. It's a tube chassis fox on ladder bars/leaf springs. but the shocks are in front of the housing and bolted to the ladder bar on the lower mount. I think I'm going to leave the bars for now and just move shocks, ditch the leaf springs and add a roll bar. Hopefully this will get the car to where I can actually use the HP. I wish I could do the whole 4 link but that's just not in the budget right now.

That being said Do you guys have a preference to QA1 or strange shocks? That looks to be the two brand that are in my budget. I'm not a chassis guy so Any other advice is appreciated.

Depending on who you talk to double adjustables from QA1 & Strange both are real close to the same as far as pecking order goes. In the past both have shown to be a decent D/A "budget" coil over shock. I don't know if it's still true but a while back the Jeg's branded lower priced D/A coil over shocks were really QA1 doubles with a Jeg's sticker on them. Might be something to look into if QA1 still produces the "Jegs" shocks.

Mount the C/O shocks behind the housing to gain the greatest amount of shock valving/dampening "stiffness" adjustment window to work with, mount in front of the housing for a "looser" valving adjustment window to work with. Mounting behind the housing generally requires a little lighter spring rate to hold the car at ride height vs in front of the housing needing a little heavier spring rate.

Longer C/O body & spring lengths generally make it easier to get the slicks off of lower ride height cars without having to unbolt the shocks. But they might also allow the driveshaft to hit crossmembers/driveshaft loops/etc while on jack stands. They also have an increased chance of the longer spring rubbing on the longer shock body (from vibration, tire shake, etc). Because of their longer length they have an increased chance of "bottoming-out", but are much less likely to "top-out" during the launch.

Shorter C/O body & spring lengths generally make it harder to get the slicks off of lower ride height cars requiring you to unbolt the shocks to get slicks off. But they reduce the chance the driveshaft could hit crossmembers/driveshaft loops/etc while on jack stands. The shorter spring/body length reduces the chance of the springs rubbing on the shock body. Because of their shorter length they are less likely to "bottom-out", but have an increased chance of "topping-out" during the launch.


Generally the "best" housing centering device with C/O shocks depends on how the car will be used.....

(1) A Panhard bar is generally better suited for street use because it can take much higher direct side loading/corner turning forces before it bends vs what a diagonal link or wishbone can handle. But a Panhard bar does pull the rear housing to one side during suspension travel. So it needs to be as long as possible to reduce the travel arc as much as possible. And it's two pivot points (chassis & housing) need to be the same height off the ground (or as close as possible) to create a smooth/even travel arc.

(2) A diagonal link is generally a stupid-simple set-it-and-forget-it centering device when used on a "drag only" car. You usually don't have problems with it if you (a) use big enough O/D tubing (b) mount it as close to a 45* angle as possible between the two sides (easier to do on a 4-link, harder to do on a ladder bar) an (c) you don't do stupid shit like hooking tie-down straps to it and bend it. Because of the whole "45* angle is best" thing generally bolt-on diagonal link designs aren't the best idea for ladder bars because they mount the diagonal link at a very steep angle between the two ladder bars increasing the chances side-loading can bend the D/link (and the housing & chassis brackets as well). For this reason IMO weld-on diagonal links (where the D/link brackets weld to the ladder bars them selves) are a better choice when using D/links with ladder bars. And bolt-on D/links work best on 4-link setups.

(3) A wishbone setup is usually stronger than a diagonal link being able to handle higher side-loading forces. But a Wishbone is a more complicated setup with a slip-joint that requires regular maintenance to keep it clean & greased so it doesn't seize up and put everything in a bind. The greatest benefit of a Wishbone is it can be mounted pointing to the front of the car or pointing to the back, it can be mounted below the rear housing or above it.

(4) An X-link setup is usually a little stronger than a Wishbone being able to handle even higher side-loading forces. There are generally two different X-link designs (a) an X-link with a slip-joint in the center (in effect two short Wishbones facing each other joined at the center slip-joint = more meant for 4-link setups), and a non slip-joint X-link (in effect two diagonal links crossed/joined/linked at the center = more meant for ladder bar setups). It should be mentioned that the slip-joint X-link design also requires regular maintenance cleaning/greasing so it doesn't seize/bind up.

Thanks for the input. It definitely helps. I just got time today to go do some looking and measuring.

So the panhard bar is definitely out. back rails are way too high.

The D-link will work in front of the housing if I extend my rear ladder bar brkt on the top hole. I can get very close if not dead on 45 deg running to the frame rail on the opposite side. And it will be pretty close to level/square with the chassis. Will this be safe at 120 mph if it get a little out of shape though? 160 mph in 1/4 mi.

The wishbone wouldn't be too much more work if I understand it right. build a triangle or horseshoe attach the side with 2 points to the frame facing front of car. install a heim joint on a slip joint in the middle and attach to the top center of the housing w/ heim joint. Does it matter how the front two points attach to the frame? heim joint or solid bolt with sleeve?

While i was mapping out the x-brace idea. It got me to thinking if i were to go to the trouble of building it why not go ahead and add a second slip joint and eliminate the roll bar? would this work? It would be mounted almost like a swingarm on a motorcycle except level. It would basically be two rectangular shaped x-braces tied together with a slip joint on each side? front 2 points tied to frame rail on each side, rear 2 points mounted near the top ladder brackets on each side.

Pic of existing suspension.

stanger68 wrote:..........The D-link will work in front of the housing if I extend my rear ladder bar brkt on the top hole. I can get very close if not dead on 45 deg running to the frame rail on the opposite side.......

Just to be clear a diagonal link doesn't attach to any "frame structure" (crossmember, main rail, kick-up, etc, etc) like a Panhard bar or Wishbone does......

The "bolt-on" style D-links must bolt it's front rod-end bracket to/through the same chassis bracket hole that the ladder bar's front rod-end does. And the D-links rear rod-end bracket must bolt to/through the same housing bracket lower hole as one of the ladder bar's bottom rear rod-end does. Using any other chassis/housing bracket hole (other than what the ladder bar rod-ends use) will cause something to bind/bend/break during suspension travel because both ladder bar & D-link must have the same exact pivot points & travel through the exact same arc.

The "weld-on" style D-links rod-end brackets must have it's "front" bracket welded to one ladder bar's bottom bar directly behind that ladder bar's front rod-end jamb nut (or as close as possible), and it's "rear" bracket welded to the other ladder bar's bottom bar directly behind that ladder bar's pre-load/pinion angle adjuster jamb nut (or as close as possible). If you have the older style ladder bar design (where the pre-load/pinion angle adjuster is in the top bars) then the "rear" D-link bracket is still welded to the bottom bar, but behind the rear rod-end jamb nut instead of behind the pre-load/pinion angle adjuster jamb nut.

stanger68 wrote:.....The wishbone wouldn't be too much more work if I understand it right. build a triangle or horseshoe attach the side with 2 points to the frame facing front of car. install a heim joint on a slip joint in the middle and attach to the top center of the housing w/ heim joint. Does it matter how the front two points attach to the frame? heim joint or solid bolt with sleeve?.....

Meh, I have seen some people attach all points of a Wishbone in "single-shear" loading (a welded threaded sleeve & just a bolt per rod-end), and seen some mount all points in "double-shear" loading (two welded brackets and a bolt/nut per rod-end), and some mount the "chassis points" in double-shear & the "housing points" in single-shear. Single-shear usually can give you a little more travel before binding when misalignment sleeves are used, but double-shear is usually always stronger, but the "correct way" is usually just a matter of opinion and how the car will be used. Just like mounting a Wishbone above housing, below housing, facing front, facing rear....it's an opinion thing that people will argue about.

stanger68 wrote:......While i was mapping out the x-brace idea. It got me to thinking if i were to go to the trouble of building it why not go ahead and add a second slip joint and eliminate the roll bar? would this work? It would be mounted almost like a swingarm on a motorcycle except level. It would basically be two rectangular shaped x-braces tied together with a slip joint on each side? front 2 points tied to frame rail on each side, rear 2 points mounted near the top ladder brackets on each side.....

The slip-joint in a "slip-joint" style X-link is only there to allow for body-roll to happen, that's why it's usually used on 4-link setups. This is because even if a super rigid anti-roll is used with a 4-link there is always some amount of body-roll happening. The slip-joint in this style X-link isn't usually meant to deal with "arc travel" since neither end of the X-link is usually mounted to the chassis, it's usually mounted to/through the exact same lower 4-link bars 4 lower rod-end holes so everything moves through the same arc.

This is all why the non slip-joint style X-link is usually used with a ladder bars since a ladder bar setup & well braced rear housing allows almost zero body-roll to happen. And since the non slip-joint style X-link mounts to/through the exact same pivot points as the ladder bar does (and not any "frame/chassis structure") there really isn't a need for a slip-joint.

Thanks for the help. I've been so busy at work lately haven't had time to mess with it yet . Can't put any braces between the bars, the driveshaft is too low. A wishbone on top would be farely easy.

Just remember that the "ideal" Wishbone overall length would be in the same ballpark as the type suspension it's being used on so they both have similar travel arcs, (or as close as possible) but sometimes that's hard to do. That's why the slip-joint is there to deal with any differences in travel arc.

But just don't go too short. Generally the shorter & shorted you make the Wishbone's overall length (vs the length/type suspension used) the longer the slip-joint's inner/outer sleeve sections will have to be made to deal with the greater & greater arc travel distances it will have to deal with. Mismatch the two overall lengths way too much (super long suspension arc vs super short Wishbone arc) and you could end up with a Wishbone that's inner slip-joint sleeve falls out of the end of the outer sleeve every time the car is on jackstands and you drop the suspension to get the slicks off.