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Front Coilover Mounting

BADaXJ

NAXJA Forum User
Location
Maine
I have been searching NAXJA and the net for a couple weeks now, trying to find pictures for mounting ideas. I want to run 12" travel remote reservoir coilovers on the front of my XJ with a stock width axle. Somewhere between 5-6" of lift, probably target around 4-5 inches of uptravel. I'll be using it mainly for crawling, and I want to drive it to the trails. Does anybody have a link to some good threads or pictures? Also, I think I can fit 10" travel without cutting into the engine bay, which could save a considerable amount of fab work, but I'd like to maintain the travel that I have now (12"). The unibody is already plated from front to rear, so I have something decent to work off of.
Thanks for any help, I appreciate it.
 
Vanimal did a pretty good job. Look for a thread called 'work party escondido'
 
Vanimal did a pretty good job. Look for a thread called 'work party escondido'
Thanks:wave:






I have 5ish, maybe 6" of lift, 12" coilovers, and a ton of uptravel right now, like 6-7". i may raise my lower mounts an inch or so to give me a little more droop, but it still works fine, especially on bigger hits. i cut into the engine bay, and that's really the only way to do it. you'll have to do some tube work or a lot of plate work if you do it like i did. I cut out the stock coil buckets on the body and mounted the coilovers right over the axle. your stock air box will have to go, and you'll have to possibly relocate things like your coolant res, relay box, etc. this wasnt too bad, i did not have to mess with the wiring, it moved nicely out of the way. working around the brake booster and master was a bit tight, but doable.
my spring rates are 225/375, and that's a good place to start if you don't have a huge winch bumper or anything. Summit is the cheapest place to get springs, i got a set of 4 for like $130 shipped and they work well.
The only other one i've seen on here with 12" coilovers is Cracker, i've never seen his setup but you may want to ask him. I would assume he made some shock hoops or something tied into his cage.

it's a bit of work, but worth it IMO. having the dual spring rate is awesome, soaks up everything. flex is great, it stays very balanced.
 
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That's nice Grimm. if i had a cage i'd probably do something similar instead of mine. i'll probably tie my towers in when that happens.
 
Thanks guys, the pictures are a big help. I don't have a cage yet, so I was hoping to avoid a more "extreme" method, but it may not be avoidable if I want to do it right. My ECU is already moved out of the way, and I don't mind moving the battery and intake etc (although I do want to install a york 210 also). but one thing I'm worried about is tire/ frame clearance at full droop on one side and full compression on the other, with a stock width axle... Obviously the trackbar/geometry pulls the droop side towards the frame, and the top of the tire on the compressed side is angle in towards the shock. Hopefully this weekend I can start mocking it up and cycle the axle.

my spring rates are 225/375, and that's a good place to start if you don't have a huge winch bumper or anything
I have a pretty substantial amount of additional weight, between the skidplates, unibody stiffeners, front winch bumper/ winch and the 3/16 rockers, but I'll probably go on the "softer" side for crawling. I won't be doing much high speed stuff, other than on the road. I was thinking of a combined rate somewhere between 175 and 200, but I haven't had enough time to really look into it yet. The front rustys springs I have now are 150lb/in and they are too soft, and the front/rear frequencies are way off and the front will flex far before the rear in most cases. ( rears are RE 3.5 with 1.5 shackle, so they are probably closer to 170 or so, compared to the listed 190 without the shackles.)

Also, I know I'm kind of crossing over the forums here, and most input here probably pertains to the Jeepspeed side of things (naturally). I figured more people over here would have ideas for the coilovers/ longtravel hardware. Having said that, I'll probably never jump my jeep or hammer it through the whoops... So, do you guys think it'll creek and crack itself apart if I'm just crawling with it every now and then, or should I be ok with the unibody stiffeners and a decent set of mounts?

My jeep is still pretty clean and most of the sheetmetal is unhacked, so if I can come up with some decent mounts without hacking it much I'll be happy...
I hadn't seen them before, but so far I'm liking the Vanimal style, since it uses mostly flat plate. I have some fab tools and skills, but I don't have reliable access to a tubing bender, so I have to keep that in mind.

Here are some "less intrusive" ideas that I liked, but they may not work with 12" of travel and the ride height I'm looking for... Just for the hell of it, the last few are my jeep how it sits now. The very last is part of the reason why I don't have enough time or money for the XJ. (ignore the goofy flares on the xj, tube fenders tied into the bumpers and rock rails are coming after the coilovers!) You can also tell, just from the pictures that the rear is pretty "stiff" compared to the front.

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the stock inner fenderwells are not even stron enough to have an airbump inside the coil bucket without caving unless they're plated and tubed up from the back, the force a coilover would put on the area would just cave it in even more if you mounted it somewhat close to the stock upper shock mount area. the stock coilbucket is re-enforced with double layers of stamped steel and it still bends if you beat on it too hard.

If you aren't willing to cut into the engine bay i would take coilovers off the table. just my personal opinion here take it or leave it.


oh, and FWIW in my build those are 14" bilstien 9100 coilovers, with the lower mounts at stock height. just to give you some perspective.
 
Yeah, that's what I figured... I'll probably end up doing something like the 2nd or 3rd picture down, as long as everything fits ok. I'll add some bracing from the unibody stiffeners, and likely do a brace across the towers in the engine bay.
 
Thanks guys, the pictures are a big help. I don't have a cage yet, so I was hoping to avoid a more "extreme" method, but it may not be avoidable if I want to do it right. My ECU is already moved out of the way, and I don't mind moving the battery and intake etc (although I do want to install a york 210 also). but one thing I'm worried about is tire/ frame clearance at full droop on one side and full compression on the other, with a stock width axle... Obviously the trackbar/geometry pulls the droop side towards the frame, and the top of the tire on the compressed side is angle in towards the shock. Hopefully this weekend I can start mocking it up and cycle the axle.

I have a pretty substantial amount of additional weight, between the skidplates, unibody stiffeners, front winch bumper/ winch and the 3/16 rockers, but I'll probably go on the "softer" side for crawling. I won't be doing much high speed stuff, other than on the road. I was thinking of a combined rate somewhere between 175 and 200, but I haven't had enough time to really look into it yet. The front rustys springs I have now are 150lb/in and they are too soft, and the front/rear frequencies are way off and the front will flex far before the rear in most cases. ( rears are RE 3.5 with 1.5 shackle, so they are probably closer to 170 or so, compared to the listed 190 without the shackles.)

Also, I know I'm kind of crossing over the forums here, and most input here probably pertains to the Jeepspeed side of things (naturally). I figured more people over here would have ideas for the coilovers/ longtravel hardware. Having said that, I'll probably never jump my jeep or hammer it through the whoops... So, do you guys think it'll creek and crack itself apart if I'm just crawling with it every now and then, or should I be ok with the unibody stiffeners and a decent set of mounts?

My jeep is still pretty clean and most of the sheetmetal is unhacked, so if I can come up with some decent mounts without hacking it much I'll be happy...
I hadn't seen them before, but so far I'm liking the Vanimal style, since it uses mostly flat plate. I have some fab tools and skills, but I don't have reliable access to a tubing bender, so I have to keep that in mind.
sounds like you have about 150-200lbs extra weight over my heep, since my front bumper is fairly light (35lbs), and i do not have a winch or skid plates.
i wouldnt go by your current springs, it doesnt really translate to the primary rate very well for coilovers from what i've noticed. your corner weight is going to be roughly 800-850lbs i'm guessing, and it sounds like you'll want 60% droop. that puts your primary in the 120lb ballpark. you can toy with the preload some to adjust.
As for the coilovers hitting the frame and the tire, i dont think you'll have much trouble. i did have a slight issue with that in the rear with 16" coilovers, but the extra travel didnt help that, and the frame is a little wider in the rear than the front. you should be fine.
 
sounds like you have about 150-200lbs extra weight over my heep, since my front bumper is fairly light (35lbs), and i do not have a winch or skid plates.
i wouldnt go by your current springs, it doesnt really translate to the primary rate very well for coilovers from what i've noticed. your corner weight is going to be roughly 800-850lbs i'm guessing, and it sounds like you'll want 60% droop. that puts your primary in the 120lb ballpark. you can toy with the preload some to adjust.
As for the coilovers hitting the frame and the tire, i dont think you'll have much trouble. i did have a slight issue with that in the rear with 16" coilovers, but the extra travel didnt help that, and the frame is a little wider in the rear than the front. you should be fine.
Great info, thanks for the help! I did a deflection test with my current springs and came out a little higher on the corner weights, but 800-900 is the ball park I was going to start with. I probably won't spend as much time as I should deciding on the spring rates and valving, but I'm not too picky and I'm mostly going to coilovers because I'm having trouble with geometry and keeping the coils happy with all the flex. May seem like a silly reason, but I've gone through many different front end configurations and I'm still not happy with it, so going to coilovers with spherical bearings will hopefully take care of the issue. Not to mention the obvious gains. As long as it's pretty mild on the road and I can hammer it down the trails I'll be happy.
 
Forgot to ask... I'm assuming you're running 2 12" coils? Is that pretty much what everyone does (equal length)? I understand you need at least a 12" on the bottom to avoid unseating it at full droop, but is there any point to running say a 14" lower and a 10" upper?
Thanks
 
i run 2 12" springs in the front on my 12" coilovers. in the rear, i run 16" lowers, 14" uppers, and a keeper spring since they're set up triple rate.
personally, i wouldnt run a dual rate with a shorter top spring as that spring is going to eventually bind, and the shorter that it is, the sooner it will. that means you'll likely need to set your stop ring at a point so that it switches to the lower spring rate before the upper coil binds, and that naturally will make it stiffer, sooner into the travel. dual 12" coils is probably going to be ideal for your setup.

Grimm gave you 2 very good links, that's where i did all of my homework for the most part. i'm still learning as i go, i did my first coilover setup in April, and the second in June/July.
 
Well I still haven't decided for sure on spring rates, but I just ordered a pair of FOA's. 2.0 12" travel, remote reservoir with the 90 degree swivels and dual rate hardware. Their damping is not specific, and they suggested "medium" compression and rebound for my uses, so I went with it. I'm not very picky and I figure I can always change it. I've read some good and some bad about FOA, but I decided to give them a chance... As for mounting, I was thinking of something similar to a conventional tower on a "framed" vehicle, tied into the stiffeners and fully welded to the inner fender with bracing, and a brace across the engine bay. Lowers should be pretty straight forward.
Maybe something like this:
http://www.ballisticfabrication.com/Coilover-Shock-tower_p_1492.html

I was thinking that if I think they need it, I could even run some hoops that tie in to the top of the tower, and spread down to the stiffeners/ rails. Once they get here I'll start cutting and see what I can come up with.
 
looking forward to seeing how you do it, post plenty of pics.
btw, making any "ready fabbed" parts like that shock tower work for the front of the xj will be a bit challenging, probably easier to make your own out of some rectangle or square tube than trying to make something not quite right work for you.
 
I'll probably make my own anyway, but I was just browsing for ideas and thinking that type of mount might work well. I used the bathroom scale method to get my corner weights, but I had a few parts pulled so I need to do the math and add that weight back in. It'll end up between 800 and 900 though... Tires/ wheels were about 85lbs and unsprung total was a bout 170 per side I think. Bumper with winch was around 165 IIRC.
 
one issue with that type of mount is the motor mount bracket bolts are right there, on top of the uniframe. doesnt leave much or any room for a bracket that goes on top lf the rails at all. plus it's a royal pain to weld down there unless you plan on pulling a bunch of stuff off your engine or pulling it. plus there's a pinch seam to deal with.
the front is a biatch.
 
I estimated (had to add bumper weight and a few other components to the measured weight) my corner weights to be between 950 and 1000lbs. Seems a little high maybe? That bumper weight hanging 2ft ahead of the axle center line has a pretty significant effect on the sprung weight at the axle. I based my spring calc stuff using 900 lbs, figuring it would be easier to add pre-load than deal with a setup that is too stiff and won't compress enough for the % droop that I'm after. For some reason, I also talked myself into going with a bit softer setup (for the same reasons)... I just ordered 225/325 from Summit, which I thought was a pretty good price at $34.99 each. Hopefully they won't be too soft, but I think between preload and dual rate stops I can make it work out for now, and put some miles on before I decide on changing any springs. I was liking the looks of 250/325 with 1000lb CW, because of the smaller step up ratio and ~140 combined rate, but I think the 225/325 will be fine for now.
 
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