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Making droop limiters


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Too much droop limiting basically means that if the surface isn't very flat the back end will skitter around on bumps. I haven't tried it, but I hear you can make the car very tail happy with too much droop limiting.

Exactly what I was imagining... something a Quaife in the rear would no doubt only worsen while it tried to figure out where to bias the torque (and while my heavy foot tries to figure out the proper pedal position for the turn). Haha, oops. :rolleyes:

 

Experimentation is of course in order, but thanks to the pointed responses in these threads it definitely sounds like a tad more droop limitation up front (relative to the rear) and minimal droop limiting in the rear (until the springs are no longer loose at full droop) may be the ideal "tune" for our application.

 

Really looking forward to messing with this. I'll be sure and post my cable implementation when the time comes.

Edited by zredbaron
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Cables will work but they are not always the easiest to adjust. In another post you were looking to be able to make changes to droop and see how that made the car handle.

 

Your turnbuckle may have anywhere from 200 to 400 pounds of tension on it depending on your spring rate and the amount of droop you're allowing. And to adjust length you will need to hold one end or the entire limiter will try and twist on you. It can work but isn't a super quick I want to change from 3/4 inch of droop to half an inch and test. At an autox you typically don't have a lot of time and may find removing the wheel, adjusting the turnbuckle, putting the wheel back on, and measuring droop takes too long.

 

My new car will have a mechanical system like a reverse bump stop. This should allow me to be able to set the droop based the stop clearance. And I could build a simple step gauge to try different amounts of droop quickly at the track. In my case I'm looking t integrate this into the front ARB.

 

Cary

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  • 3 years later...

Finally finished up the front droop limiters today. I did end up running cables and turnbuckles. Thinking at some point I may have to change the location and style of sway bar, and if I do that then I might do a different limiter, but this will work for now. I wanted to have the quick release pin, but having it at the bottom doesn't seem like it's going to work very well. Might have to switch to a bolt there and pin between the turnbuckle and the cable. The cable doesn't line up with the sway bar very well, so it's pulling at an angle on that little cotter pin.

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Edited by JMortensen
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I don't think that ducting to the brakes will be a big issue. Won't actually need ducts for a while, will be autoxing until I'm comfortable in the car, but when I do need them the plan is to run a small backing plate bolted to the spindle with the hose connecting to that to force ducted air into the center of the rotor. Shouldn't be hard at all to route the hose around the cable.

 

Having the limiter connect to the bottom of the spindle would mean more room for ducting, but outside of that I don't think it makes much of a difference. Connecting to the sway and having rod end end links should be pretty solid too.

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  • 4 weeks later...

Wow, really surprised to hear that! Glad it happened on jack stands and not on the track.

 

Several months ago I looked into sourcing cables / ends / turnbuckles from sailing accessories manufacturers. Composite sailboats have turnbuckle-tightened cables for their mast(s), and they are subject to considerable loads, most notably when the main sail swings from one side of the boat to the other.

 

Thought I'd share in case you were looking for a new hardware source. Unfortunately I didn't bookmark the manufacturer's URL. Google "sailing turnbuckle rigging" or variants and you'll see several. Not sure how pricey they are or are not compared to other solutions...

 

Thanks for updating us, Jon.

Edited by zredbaron
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I'll keep the sailing hardware in mind, thanks. I just replaced with cables and ferrules, will see how that holds up. Since I have the turnbuckle for adjustability, this might be all I need. Those ends sure looked nice though.

Edited by JMortensen
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Cool. I'm probably not the only one interested in pics of your final solution whenever you get a chance.

 

I'm still debating where to attach the upper end of my droop limiter. Unlike you, I still have my stock fenders and firewalls in the way, so I was thinking it would be nice if I could fabricate something that would mount on the underside of aluminum camber plate holding the bearing / top of the strut.

 

I don't like the idea of it tugging on the plate, and I don't like that it won't be parallel to the strut. (Perhaps both are moot?) I haven't come up with a graceful idea yet. Thoughts?

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The plate should be plenty strong to handle the couple hundred lbs you're going to put on it with a droop limiter. The angle doesn't really matter unless something else is in the way, because it's just a stop, so it's not like leverage ratio or anything else matters.

 

I like the idea of having a hook that goes over the swaybar end links and then an adjustable stop, maybe that screws in with a jam nut. I tried to figure that out a while ago and decided cables would be easier, but that's another way to do it that should be possible and maybe less messy than cables.

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I used cables and turnbuckles on my car.  The top mounted with nothing more than a fender washer and a bolt.  The connection was pretty much what Jon showed in his pictures.  Nothing ever bent even with numerous off track excursions with wheels in the air.  One nice side effect of running them is that you don't have to jack the car up as high to put wheels on.  

 

Version two for me was going to be a stop that was under the ARB arm.  I saw a few older sports racers running something similar and owners said no issue running up against the limiter.  The did say it was a ton easier to adjust these to keep abreast of ride height changes.  

 

Cary

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Gotcha. Speaking of ARB arm... I noticed that most of the droop limiter pics (from various users) are mounting the bottom half of the limiter to the ARB arm instead of mounting directly to the control arm. Does this also not matter since they are attached to one another anyway? (Tidier solution due to a shorter cable?)

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If you mount the cable to the arm, you want to do it as far out as possible. If you mounted closer to the pivot, then your adjustments have to be more exact because 1/8" movement 3" from the LCA pivot might be 3/4" at the wheel (not exact, just making the point). Unfortunately at the end of the control arm there is a bunch of crap in the way; strut housing, sway bar, ball joint, etc. Using the sway bar allows you to get farther towards the end while avoiding all the other stuff.

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You'll probably wind up having the same problems with sailing hardware as you did with other hardware, sailing hardware is a lot stronger than regular hardware, but its designed to hold tension, not shock. Wires and fittings from the lighter dinghies like to stay at a constant tension. You may be able to get away with it with a strong fastener set up and a protective tube to avoid fraying in the wires

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