[ethrjock]

Just passing along some real life experience with the BMR LCA drop brackets in my phonto sold by BMR.

First off I put these on about a month ago and they really help the tire shredding I was doing. Even with the street tires I had (factory tire) traction improved 200%. Worth every penny.

Here is the deal though.. I had read some posts that welding them on is optional so that's what i went with. No weld, bolt on only.

While at the track last weekend the car was hooking well...like usual with the MT drag radial setup I am running. On the way home the rear end was whining like something was wrong. I got under the car and saw right away that the bmr lca bracket had pivoted about 1/4" on the axle mount. You could clearly see the original line where the brace had been.

I measured the pinion angle while i was at it and my negative 3 degree was gone too. It was now 3 degrees off.

Luckily my neighbor has a welder. We loosened up the bracket and repositioned it back to the original spot and welded it in this time. (after using a wire wheel on a grinder to clean up the rust on the axle and removing the

Moral of the story...if you are hooking up with a sticky tire and using these BRR LCA drop brackets ... weld them in like BMR suggests.

 

[07stanggt]

So the bracket didnt bend anywhere? It just moved. This caused the rear to whine? Interesting did the whine go away once you welded the bracket?

 

[ethrjock]

TBD on the whine (still up in the air awaiting my gt500 fuel pump install) but the bracket did not bend and after I loosened it up I was able to pry it apart and reset it back into the original location.

 

[orangemonster]

well they suggest welding if you use slicks or if your 60' is under 1.7.

 

[joeice14]

I was having issues welding mine, you just grinded the rust and powder coat down... I am using a mig with steel wire... Did you paint over the weld to stop rust afterwards???

 

[scramblr]

Shouldn't be a heads up since the instructions are pretty clear about welding, but at least you're bringing it to people's attention. Glad it was not catastrophic for you. There's another car that completely bent the passenger side bracket and tore up the wheel well. Almost went into the wall.

 

[07stanggt]

How does it move without bending the bracket a little bit at least?

I am interested in this since rear end noise has been a problem for me.

But im confused.

So the bracket moved forward towards the front of the car? Or backwards?

 

[ethrjock]

bracket pivoted backwards. I suppose the bracket "flexed" some but it did not bend that I can tell. After unbolting the single bolt that clamps it to the factory axle bracket and prying it a part a little i was able to move it with a rubber mallet.

I used some red rustoleum to paint over the welds. I used a mig welder too with .035" wire set at high and wire speed of 5. Removing the powder coating and the rust from the axle is important...otherwise it will splatter and not make for a clean weld. I will try to take a photo of the finished weld if you want or it woud help some others.

Like I mentioned..after I get if off the jack stands I will see if my axle wine is gone.

What pinion angle is everyone else running. Mine is at negative 3.

FWIW..I am running MT Drag radials 28.1" tall and 12" wide on 15" x 10" weld racing rims and my normal 60' is from 1.7 to low 1.6

 

[stanglifemike]

Is that your welder Steve? I need to weld mine in too. I wasnt to worried before the supercharger, but now I would like to weld them in. Also thought about putting mine on the alignment rack and making sure my thrust angle and pinion angle are good and then welding them in.
Nevermind - learned how to read......its your neighbors welder

 

[07stanggt]

Interesting

big and littles, a blower, and a line lock even i would have said weld them. And i think im the only guy on the net who admits openly to not welding the brackets.

Good luck on the whine. Usually it doesnt go away once you have it.

 

[06GTMustang89]

rich whats your 60'? cuz you don't have yours welded in and youve been alright..i mean i welded mine but with .025" copper wire...but im also N/A so there isn't as much force as you S/Ced guys

 

[07stanggt]

This issue still perplexes me.

 

[Anthony05GT]

Pinion angle of -2 degrees is what most people go with.

 

[07stanggt]

rich whats your 60'? cuz you don't have yours welded in and youve been alright..i mean i welded mine but with .025" copper wire...but im also N/A so there isn't as much force as you S/Ced guys

1.704 with 350rwtq and a 5k chirp chirp chirp go to second. Last year mostly in the 1.8xs 3k drops dead hooking.

This issue boggles my mind really. I cant invision it and that annoys me.

for this thing to simply move 1/4 of an inch but not bend the back arm of the bracket confuses the piss out of me. The LCA is tubular steel one length. The length of the LCA and the location of the bolt hole in the bracket determines location of the rear.

For the rear to move and the pinion angle to change 3 degrees the rear had to twist/turn/pivot forward The uca has it located on the top.

So it turns..bottom part of the rear towards the front of the car. Right? to cuase a positive pinion angle change thats how it has to turn. Litteraly the tires are now rolling closer to the front of the wheel well by a 1/4 inch.

What did the left side do out of curiousity?


Sorry not trying to hog up your thread I just cant invision this. Its like have a word on the tip of your tongue but you cant think of it.

With those big tires your lucky it didnt rub.

 

[ReverendDexter]

1.704 with 350rwtq and a 5k chirp chirp chirp go to second. Last year mostly in the 1.8xs 3k drops dead hooking.

This issue boggles my mind really. I cant invision it and that annoys me.

for this thing to simply move 1/4 of an inch but not bend the back arm of the bracket confuses the piss out of me. The LCA is tubular steel one length. The length of the LCA and the location of the bolt hole in the bracket determines location of the rear.

For the rear to move and the pinion angle to change 3 degrees the rear had to twist/turn/pivot forward The uca has it located on the top.

So it turns..bottom part of the rear towards the front of the car. Right? to cuase a positive pinion angle change thats how it has to turn. Litteraly the tires are now rolling closer to the front of the wheel well by a 1/4 inch.

What did the left side do out of curiousity?


Sorry not trying to hog up your thread I just cant invision this. Its like have a word on the tip of your tongue but you cant think of it.

With those big tires your lucky it didnt rub.

Axle wrap.

A strong launch is going to try and rotate the axle "backwards". If the bracket isn't secured, the axle would rotate inside the bracket, moving the bottom of the bracket effectively rearward.

 

[IronStomach]

The picture is confusing because you can't see any of the three mounting bolts used for the brackets.

What Rich is trying to say is that it's impossible for the brackets to rotate without bending... unless the top mounting hole that faces fore/aft wasn't bolted in. Go look at BMR's product install pictures.

But I'm sure the bracket can just be bent back into position without much worry, so long as they're welded now.

Good luck and thanks for the heads up!

 

[stanglifemike]

Steve(ethrjock), you need to change that time under your avatar now. What was it, 11.8?

 

[jwgroovin]

Here's another example of what a 1.6x sixty foot can do to an UNWELDED lower control arm relocation bracket (passenger side). Lesson learned, happened last year:

 

[ethrjock]

welded

I thought more about the question on how come the bracket did not bend. I remember the upper bolt where the vertical bracket bolts up... it was moved too. It shifted up. With that bolt moved up that would explain how the bracket pivoted 1/4". It was not until I loosened that top bold that the bracket would move back into the original position.

Also. Before I adjusted anything I measured from the front of the lca mount to the top bolt on the bmr bracket. There was 1/4" difference from one side to the other. one was 18.5" and the other was 18.75". The axle was in a twisted situation but was corrected when I readjusted the brackets. You have to be careful when adjusting these. You need to make the same turn from side to side otherwise they will be out of alingment form each other. I kept measuring and counting turns to ensure they were equal length from the front LCA mount.

Also, since one side had moved and the other wasn't the pinion was still off. After i got it all aligned up I had negative 4 degree on the axle and negative 1 on the input shaft of the rear end.

The photo was taken with my iphone so t's not the best. Functional for sure but not the best form.

Mike. I am sure my neighbor will loan it to me to help you out. We should weld those in before the MCE day on the 21st.

 

[ethrjock]

Steve(ethrjock), you need to change that time under your avatar now. What was it, 11.8?

Time updated Mike. :rockon