Discussion in 'Offroad Projects' started by Ronin8002, December 20, 2012.
Thank you James
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After looking it over and taking a few more measurements, I think I have found some improvements to the lower brackets:
-The lower strut bolt starts to bend in the rearward wall of the lower control arms when you torque it down. Normally this doesn't happen because the OEM strut assembly lower eyelet has a steel bushing in it that the bolt and nut squeeze against, so I will slide a bit of tubing in there over the bolt to prevent that
-when I designed the lower bracket, I simply measured 3" up from the lower strut mounting hole, when the strut was level. This works OK but since the new setup angles the lower control arms downward,it puts my lower tabs at a greater angle than I want and also a steeper shock angle than I want. The bolt head does clear the CV boot in this position but is quite close. What I need to do is measure 3" up from the strut bolt hole when the arms are angled downward. This will give me the true effective extended length I am looking for and move the lower shock bolt more inboard to have greater clearance from the CV boot. Right now the coilovers plus brackets have an effective extended length of 23", I am looking for something closer to 24". This also means that the lower mount tabs will have more of an isoceles triangle shape (like in Corkey's setup) rather than the equilateral shape that I have now.
-I will try and incorporate the lower limiting strap mounting tab into the new lower mount design.
Once I have all this worked out I'll post up pics.
why don't you consider what we have disused before? would be much easier to do? and it will preserve OEM geometry
It's actually easier for me to cut and weld brackets (now that I know the measurements of everything) than to cut up my OEM struts and have parts machined.
But...it might be useful to cut off just the OEM strut eyelet and weld the plate/tabs to it to make a lower mount. I'll have to consider that.
I will get you those measurements soon...was out last night.
Ok figured out whats going on. By installing the new shock tabs right over the old strut mounting hope, I created a different arc for the shock pivot point as the suspension travels, which accounts for the lower amount of droop travel I am seeing. So, when i make the new mounts i will just offset the hole inboard 11/16" and that should bring the new lower shock mounting point back into the same arc that the oem lower strut mount followed. This should give me the expected amount of downtravel and also raise the ride height a bit more.
finished cutting out and drilling all the pieces for the new lower mounts today. Should have it all welded together in the next day or two...I'll take some pics when the brackets are done.
Looks good man!
New lower brackets are welded up:
I improved the joint design on the lower strut mount tabs...the front one is now an open outside corner joint, and the front coilover tab was beveled at the bottom to allow for a groove weld on the front side (still did a fillet weld on the back). Then I made a final pass and weaved the bead to tie in the coilover tab and the open corner joint on the lower strut tab for a good strong connection. I also have put a gusset between the two tabs on the inboard side for extra reinforcement.
The holes in the coilover tabs are now offset about .5" inward from the OEM lower strut mounting hole to correct for the change in the movement arc caused by the height of the tabs. I also drilled the correct size hole this time (18mm) in the lower strut mount tabs for a tighter fit. The pieces of 1.5" square tubing will go inside the lower control arm between the two lower strut mount tabs to give the OEM lower strut bolt something to squeeze against when it gets torqued down.
I looked at including a limit strap tab on the mount but either the shock or something else would end up getting in the way of the strap, so I'll have to figure out something else for that. Looks like the best place might be to put the lower limit strap tab over near where the swaybar link goes.
Just need to paint and install. The decreased shock angle should give me a bit more lift and downtravel. I'll make whatever adjustments I need for the camber from the altered setup...probably will also try and do some toe adjustments also. The rear wheels have some negative camber from the truxxx spacers so I'll fix that too. After that I'll get it professionally aligned...hopefully it won't need too much adjustment since it should pretty much be in the ballpark by then.
Looks good, I wish the 3rd gens arms were more like the 4th gens, I really like this setup.
This is an amazing writeup. I like how you listed out everything all in one post well supplies at least. The ex is looking sweet. I remember when you'd said you weren't going to do much with this one haha.
they look pretty beefy,, and well done ,
Thanks, I installed them over the weekend. Much more of a precision fit than the last ones and I am confident that these will hold up to abuse better too.
Overall travel is better now since the shock is now pushing along the arc of the control arm as it cycles rather than more outward. Lift went up a little, but what I also noticed is that preload adjustments have more of an effect on ride height than they did before. I'm going to keep the passenger side at zero preload and the driver's side at about 3/8" preload, that keeps both sides at the same level height.
For fun, I took the spring off one of the coilovers and cycled the suspension on that side from full droop to full compression with everything hooked up except the swaybar. Actual total travel at the wheel measured out to be 7.25" When I first started this project I calculated 8.5", but where I was wrong was the motion ratio of the suspension changes as it cycles, so that means you get less shock movement to wheel movement as you get closer and closer to full droop. No big deal, it's still a huge improvement over stock, which has got to be less than 4" of travel based on what I know now.
Much more than 7.25" and I would be stuffing the tire too much at full compression, and at full droop the upper control arm would hit the brake line bracket. Also, still need limit straps for the last .25" of droop travel as there is a bit of CV boot rubbing on the coilover mount tab at that point, but for normal street driving it will be fine for now.
Also, I checked to see that the shock is approaching (but not exceeding) a perpendicular angle to the lower control arm at full bump. Fortunately, it is...Looks to be about 83 degrees (perfect would be 90) but this is close enough.
Ride quality is maybe a little better than with the old lower brackets...could just be in my head but it feels a little "tighter" for lack of a better description.
Final alignment will happen this week. I've got the camber pretty much as dialed in as I can get it with my bubble level. I'll probably just leave the toe for the alignment shop but I can see that it's toeing in too much right now.
Good to see it done and all worked out!
Alignment is done, made a huge difference in how the steering feels. With that all taken care of, I took it for some long highway drives and was amazed at how well the front suspension soaks up rough patches and potholes...rides like a dream!
I've completely removed the front swaybar and there is no weird handling even when I take exit ramps fast or swerve back and forth quickly...so I am going to keep it off for the long term to take advantage of the extra flex.
Limit straps will be this week's project.
Congratulations James and thanks for the excellent write up
First of all, super nice build! I'm a huge believer in proper suspension travel, from trucks to sports cars to dirt bikes.
But, is the stock travel really 4"!!!??? That's horrible. My Vette has more travel than that! Here's a shot of a Z06 at full droop:
And the car will easily tuck the tires at full compression.
What's limiting our stock travel? A super short travel shock?
4 inches at the shock is way more at the end of the a arm,,
I believe Ronin said it's 1.5" at the shock, and 4" at the wheel. But correct me if I'm wrong (hope I am).
According to the specs on Monroe's site for their OEM type replacement struts, they have 2.83" of travel. With the springs installed on my OEM ones it's hard to cycle them completely to get a measurement, but if you calculate the motion ratio from the suspension links and factor in the strut mounting angles, it ends up being around 4" at the wheel. Most of that is uptravel.
Setup has done well and held up to offroading. I've made a couple of little changes recently though.
-the 750lb springs settled and I wanted to crank up the preload, but there just wasn't enough travel in the springs to do it without causing the coils to bind at full compression. So, I got a set of 12" long eibach springs with an 800lb rate. This raised the front back up a bit and will also allow for up to an inch of preload before coil bind.
-I noticed that the bolt heads on the lower shock eyelets were rubbing the CVs boots a bit at full droop. Wasn't too big of a deal but just kind of annoyed me, so I made another set of brackets that offset the mounting point forward about 1/4" and inward about 1/2", now there's no clearance issue.
-I have welded some limit strap tabs to the lower control arms and installed some threaded limit strap clevis mounts through the top of the shock towers. Currently using 15" straps...they seem to work fine.
Still rides great overall and I am still glad I ditched the front swaybar after lots of street driving and some offroading
I'll post pics of everything when I get a little extra time.
see, i said the sway bar wasn't needed on my 96 too, it just works that much better,,
good work, glad it's working great,,
Here are some pics of the new lower bracket setup.
The lower bracket was made out of a 2.75” section of steel angle (aka angle iron), 0.25” thick, and it has 3.5” long legs. I cut it at a 15* angle so that the CV boot would not rub the bracket at full droop. I also shortened the leg on the front side of the LCA so it would sit nice and flat against the front of the lower control arm. I also beveled the leading edge of the part that sits flat on top of the LCA due to the shape of the LCA. Once I cut it out and shaped I drilled a hole for the lower strut bolt to pass through the bracket so it would be clamped to the LCA. Otherwise it just sits on the flat part of the LCA over the old strut mounting hole.
For the shock tabs, I used this bracket from ruff stuff specialties and just welded it on: http://www.ruffstuffspecialties.com/catalog/SBRKT-FLT.html
Notice I had to offset it inboard so it’s closer to the inner LCA pivot, and it’s also offset more towards the front edge of the bracket. This lets the bolt head that holds the lower eyelet of the fox shock to clear the CV boot at full droop.
On to the pics:
View of the lower bracket from the front at ride height:
View of the whole setup, full droop:
Overhead view of the lower bracket at full droop:
UCA angle/clearance and spindle to spring clearance at full droop:
View of the whole setup, with the suspension jacked up to approximate ride height:
Overhead view of the lower bracket at approximate ride height:
Limit strap at approximate ride height:
I finally figured out a way to convert the rear over to Fox coilovers as well, so I've ordered some 6.5" travel shocks and all the parts I need to make it work. This should be a bit easier now that I sort of know what I am doing. Should start getting my parts in next week and I will probably begin working on the brackets this weekend. Stay tuned for updates.
Looking forward seeing that happen!
I Like the way you think James
wonder why nobody is doing a "knuckle" lift...
With as much fab and calculations that were involved in this setup, would it be that much harder to do a knuckle lift like are popular with GM full size trucks? You know, dropped bracket across LCA frame mounts, and a spacer atop the factory upper ball joint mount of the knuckle and either coil-overs for more travel, or reuse factory struts with a spacer between upper mount and frame if you were only after lift and not more travel. Additionally, if you were to fab up cross members for LCA's, you could move the new mount points more inboard and run longer LCA's to match the extended UCA's already available. This would bring the Short/Long Arm relationship back to stock, but, you'd need to extend your steering rack end links by this amount as well so it won't cause toe angle changes as the suspension jounces and rebounds.
All of this would maintain stock track-width and bring the arms back to working in the mid-point of the circular arc that is their travel path, rather than going more extremely in as they travel downward. As you lift an independent suspension by forcing the arms more downward, they are also moving inward, sacrificing track width which can make the truck less stable (although probably not severely so, I would just prefer to keep as much stability and linearity in suspension travel as possible).
By the way, awesome work figuring all those variables out and gettin' some more air under your X! Just thought I might put a bug in someone's ear who might be planning something like this in the future