LCA's relocating brcket, Hype or do they work?
 

Ok, here is my delema. I have read a bunch of books on suspension set up and they are all saying the same thing. Relocating the rear of the lower control arm down on a torque arm suspension does nothing for lift/tire plant. This is do to the fact that the torque arm is fixed to the rear axle and has no pivot at the rear. The lower control arms do nothing more than halt forward and backward movement. This does not hold true for a GM style 4 link rear suspension as the upper control arms are mounted with a pivot at both ends thus the lower arms have all to do with wieght transfer/lift. If you were to change the angle of the upper or lower arm in a GM 4 link suspension then you change the instance center of the car. If you change the angle on a torque arm suspension then the instance center does not change as it is directly related to the position of the torque arm. So, I ask again, is the rear LCA relocating bracket on a F body nothing more than advertising hype IE: it worked on the chevelle suspension so it has to work on the F body suspension? I think the consumers have been dup'ed! Of course it bears the question are they effective on a drastically lowered car as they will bring the arm back to level and ward off wheel hop due to a negative angle. Hum.......... So, what say you? :chug:

The reason relocation brackets are used is when you lower your car and change the geometry of your stock set up. I lowered my car and due to the drop difference everytime i took off the line it felt like my whole rear end would rattle loose. I put the reloc brackets and adj. LCA's in and completely stopped the axle hop and hooks great now.

Granted, i still need to get an adj panhard bar and torque arm.....but atleast im not going to break n e thing. So are they important enough to get? Not in my opinion if you do not have a lowered vehicle.

I have seen them knock a .10 off the 60 foot WillyZ 93 z28 m6 with a lt1 396 with 9 inch and 3.90 gear and subframs, short torque arm QA1s stock springs

he changed all that and only shaved .1 off of his 60 foot time???

NO he had all that and he decided to try the brackets and see if they would help . prolly had 50 passes to get the best compared to the fist night at the track and it picked it up a tenth. And if you dont think a tenth in the 60 is somthing you are crazy .

I have to disagree. They helped me knock .1 off my 60' and I'm at stock height.

Now that was what I was looing for. someone who changed just one part and recorded the difference. :chug:

.15 off my 60ft with no other changes
It was one of the first suspension mods I did, 2nd only to new LCA's.
And you can easily see/feel it lift the back of the car all the way till it tops out the suspension when you hold the brake and gas it.

Edit: I'm at stock height

drastically less wheel hop which means i can hold it to the floor instead of pedalling

So that comes back to my origanal statement do they help with traction by adding lift or just control wheel hop? Being able to hit the gas harder by controling wheel hop is just a by product. :chug:

You're contradicting yourself, It does plant the tires harder when you lower the rear mounting point of the LCA. They don't cost much, try it. You will have no doubt.

my car is very tight in the 60ft. before the brackets it was 1.538-1.543, with the relocation brackets and no other changes, it hit a best of 1.513. most of the passes are between 1.518-1.523 now.

Unfortunately I cannot try a set as I sold my F body. They did work in my chevelle but I have since swapped to a fab 9 housing that has such features built in. I was just curious as I found this info in herb adams suspension tech book. And yea, I can't spell either! :chug:

lol, I wasn't poking fun at your spelling. I was providing a link with some relevant info.:chug:

what Madman posted in the instant center post is the same jargon that the herb adams book stated for the 4 link style rear. After reading Madmans post I would say that it is also true for the T/A suspension as well. Maybe not to the same degree as the 4 link style. By this I mean that the T/A rear will react differently to say .5" of bar end change that a 4 link would at the same .5". Reason being is the T/A is much longer and the angle change would be less. Good info. :chug:

"Anti-squat" is the operative concept that hasn't been touched on much in this thread. I will say there is some misinformation posted.

I don't pretend to be modest and I'm way too lazy to retype or C&P all of this stuff from almost 4 years ago, but the bottom line is that relocating the rear pivot point of the rear lower control arm (via brackets) does change the Instant Center and therefore the anti-squat of the F-body torque arm suspension. Increased anit-squat equals more load on the rear tires during forward acceleration, so yes, that can help lower short times as some on this thread have noted. There are some down sides also, but there is rarely a free lunch.

Trooper's link was pretty good, but start reading at (my) post #46. The OP wasn't quite correct:

https://ls1tech.com/forums/advanced-...-center-2.html

There was another thread on this topic on another forum:

http://www.camaroz28.com/forums/showthread.php?t=391537


My $.02.


Jon

Is there any benefit or harm when not using the car for drag racing? What about for street or auto-x?

Better traction launching on the street is the benefit with the LCAs mounted lower at the rear.

Auto-x benefit would be corner exit traction but must be balanced with the other mods as a tuned package.

I think on paper the rear should be looser in corners (oversteer) but since my front swaybar is off along with several other drag racing compromises, I drive it semi sanely on the street and haven't experienced first hand it's high-speed cornering balance.:D It does handle plenty good still and is not at all unstable or dangerous. Just don't drive it like a corvette at high speeds (mostly due to the missing swaybar not the LCA relocates).

There's alot of good info in this thread already. My opinion on this subject- If you eliminate wheel hop, you get more traction. The more traction you get the better. The main thing everyone needs to remember, is that you need to have an uphill angle on the LCA's towards the front of the car. Meaning, the rear mounting point (rear end) of the LCA's needs to be lower than the front mounting point (body). If the LCA's are level, it will work, but a more drastic angle will have a better affect on the car's ability to transfer power to the ground.