I have the UMI LCARBs on my car. I was just wondering what the middle set of holes on the brackes are for? I have the top hole monting the bracket to the rear. I have the the LCAs mounted to the bottom set of holes, so whats the middle set of holes for?? ride hight, and if so would moving the LCAs to the middle holes lower or raise the rear of the car?? Thinking it would lower the car if thats what the holes are for?

 

for a different lca angle on cars not dropped a hole lot. It will do nothing or little for ride height, the ride height depends on the springs mostly.

 

Yup what he said. If your car is dumped 1" or so you probably use the middle hole (could use the bottom hole too depending) or if its dumped 2.5" or there abouts you are kinda forced to run the bottom holes just so your LCA's dont hit the bump stops on every little bump.

 

yeah, My car has 1" drop springs..I do remember having trouble when I put the LCAs into the bottom holes. I'll be changing over to UMI LCAs next month so I'll fix it then. So if I follow you guys correctly, I should just use the hole that the LCAs best line up with?

 

Use the hole that either keeps the LCA level or slightly lower in the rear. The whole point of LCARBs is to keep the rear mounting point level or lower than the front mounting point.

 

Read up on anti squat for more info.....

 

Use the lower of the two holes. I talked to UMI just the other day on the phone and the lower of the holes is more for "drag" purposes but gives more traction to the rear, the top hole is what you'd use to bring a lowered vehicle back to "stock" i think it was.

Could be mistaken though.

I have mine on the lowest hole.

 

It's a "tuning" thing.

Use whichever one you prefer how it makes the car work.

You'll generally find that if you lower them TOO much, it'll have wonderful "leave", but will wheel-hop SEVERELY on hard braking; because then, instead of making the car "neutral" in that respect by placing the instant center (the imaginary point where the suspension exerts its force on the car) at the center of gravity, you will move it to the opposite side of the CofG from where the messed up factory geometry locates it, and it will behave exactly the same as it did in stock trim, except in reverse (when the force is tending to pull the rear end rearwards instead of tending to push it forwards). Too much lowering in a drag race situation will make it hit the tires too hard and then bounce and unload them.

"Optimum" is usually where the axle end of the LCA is slightly below the "frame" end; about ½ - ¾" lower. That's where the IC and CofG are near the same spot.

 

Pretty good answer William!

Also, agree on this one.

For a daily driver with no drag racing aspirations, the middle hole works great to angle the arms slightly downward at the rear in most cases.

This situation is very similar to the adjustable torque arm. Most customers choose the extreme adjustment to start with. If we get wheel hop or other weirdness, then we look at moving stuff back closer to stock.

In 99% of the cases, lowest hole works fine with no negative effects.

ramey

 

Ok, I'll leave the LCAs in the lowest holes...Thanks

 

If it helps I've got mine on the lower with no issues. I do notice improved traction when exiting a corner with no wheel hop issues