In January of 2005,installed BMR bolt-in LCA relocation brackets and launch traction immediately/dramatically improved.
I'm 'old school' of an era back to the original 'muscle car' of the mid to late 60s'. Back then,'lift bars' were used to enhance launch traction. The lift bars were used to take advantage of rearend housing rotation during acceleration. For every action,there is an equal opposite action. As acceleration,and/or start of acceleration occurs, and the inertia of trying to move the vehicle,from a stop,forward,sometimes as violently as possible like we like to do,the pinion wants to climb the ring gear and as it's trying,it's taking the 'snout' of the rearend upward too. this upward rotation tries to move anything below the centerline of the axles forward. In the 'old days',lower control arms on GM 'muscle cars' had the attaching point at the rearend housing lower than the attaching point at the frame. As the rotation of the housing occurred,it pushed the LCA forward,and since it was angled upward,it attempted to push the frame/body upward,and because of action/re-action,the rearend was pushed downward increasing traction. But because the angle of the LCA wasn't far from level,the upward push was small,but still traction enhancing. 'Lift Bars' were used to take that small upward push and change/convert it to a very definite and strong upward push.
Camaros,back in the day,had power and a beefy rearend. As time went on,with EPA regs,insurance,and gas shortages,power levels dropped and because a beefy rearend was no longer necessary because of low power levels,GM applied the little 7.5 10 bolt from another platform to the Camaros. As power levels increased in the 4th Gen,GM (I believe) angled the LCAs downward,from rear to front,thereby purposely decreasing traction to save the little rearend from breaking due to traction and not having to design in and supply a beefier rearend. That would also keep costs down to stay competitive in vehicle pricing.
LCA relos take the geometry back to 'old school'.

In March of 2005,I measured,dimensioned,and made a side view full scale drawing/layout of the rearend area.

the OEM LCAs are angled downward about 3 degrees,the relos change the angle to about 6 degrees upward (lowest relo hole),a change of 9 degrees. As you can see from the drawing,I made extensions (3 different versions). The further I lowered the LCA end,the better 'launch' traction was.

In June of 2005,I put these on.

Ran those until April of 2006 when I put these on

Ran those until April of 2008 when I put these on.

ran those until 2009,I'm currently not using any extensions,I got a totally different design in the works.
They worked well,better than I thought they would. As I changed design,traction increased.
The 'flaw' with the design was a flat tire would allow the extension to contact and scape on the ground. No,it didn't happen to me.
What started out as some 'testing' ended up as necessary when I put 4.56 gears in 2007.

 

Any other downside to doing this?

 

Other than the 'flat tire scenario' being catastrophic,no. I put about 40,000 miles on with the 3 versions. Never encountered the theoretical loss of braking traction,even under hard emergency stops. Wet pavement acceleration traction was a benefit,so was trying to take off in snow. Handling never suffered. Rearend alignment never changed as the holes were 'manufactured' to allow the swinging arc necessary for the LCA. Ride softness/harshness never changed as that's controlled by springs/shocks.

 

here's rear view of the 4 situations

 

Interesting. Never really thought about this that much. I see what you're saying and it makes a lot of sense.

 

The downside to watch out for is brake hop. You can't just
get launch bite for free in a fixed torque arm setup. And you
probably won't know you have a brake hop problem until you
either go looking for it, or a panic situation comes looking for
you. Have to put it to the test on some wide lonely pavement
with "panic stops".

 

I commented on that in post #3.
The relos only,I was running OEM shocks.
With the extensions,the pics show QA1 double adjustables.
With the OEM crap shocks,I probably would have encountered 'braking wheel hop'.

 

Do you have any of them still laying around?

 

It was a test,a test to determine how 'launch' traction increases by changing the 'push' angle of the LCA,a test that should never had lasted as long as it did. I have to consider myself incredibly lucky to have not have had a flat tire while in motion with those extensions on.
Think about how catastrophic it could have been,even deadly. A 4000 lb. car travelling at 100 mph has how much potential energy ? Enough to destroy a car ! Now,imagine that energy concentrated at that extension impacting and digging into the pavement. Destroying rearend,rearend connecting points,torque arm,driveshaft,causing loss of control. Those extensions are never going back on,IT WAS A TEST. The design I'm working on does not have that design fault but should actually apply more 'lift' than the extensions did. I do miss the enhanced traction of the extensions,but also looking forward to the 'in process' design. It still utilizes the LCA relocation bracket because of its' sets of holes. Without all those holes available for mounting,welding would be necessary and I don't like welding mods as they're too permanent and not easily changed.

 

Exactly, & the lower the rear of the arm gets the worse the condition will become. Your changing the instant center.
The decel/braking wheelhop could get pretty nasty in certain conditions.

 

Hitting the pavement with suspension and frame parts at highway speed isn't as horrible as you make it seem; I've seen it a couple times, and aside from tearing whatever bit up that hit the ground, it's not that bad. Especially in this case, as unless you have a blowout, you're never going to instantly drop directly onto that LCA. You'd tear the LCA and the mounting brackets up (and probably the wheel, with that bolt end hanging way out there) and probably tweak the rear alignment, but that'd be it.

 

What about cornering? Isnt the lower the arms sit, affects cornering?

 

Yep. How hard you drive the car in the corners will determine how much you feel, but most auto-cross and road-race guys don't drop the rear LCA mount much because of it.

However, in an all-out launch traction car, it might not be a concern. Not something I'd want on a street/strip car though.

 

Just go ahead and weld on some training wheels to the LCARBs

no more flat tire worries. haha


...but seriously, cool concept.

 

I was thinking about some kind of 'skid plate' addition to lessen/minimize flat tire concern,even had one drawn up,utilizing the lowest cross bolt and shock mounting bolt.
With the 4.56s',Yank SS3600,Nitto 315 drag radials,I do miss the traction I used to get.

 

I'm pretty sure its against NHRA and IHRA rules to have point of the car hang below the rim incase of a flat tire or anything like that.

 

Just as an FYI, having witnessed the results of suspension components and even brakes hitting the pavement at high speed...it really doesn't do too much. Because of the angle of the arms at the extreme point, it will dig up some asphalt or concrete then slide. It will round off the metal, and that's about it. Even having a front control arm failure (ie. lower ball joint breaking and the front control arm hitting the ground and "digging" in) the worst damage comes from the front tire folding back and hitting the fender. The control arm continues to drag along the pavement. Worst case would be a drive shaft front u-joint failure in which the drive shaft "could" dig in and cause a violent lift of the rear of the car. This is the reason they require drive shaft safety loops. You would have to worry more about the front mount on the control arm failing and dropping....that could potentially cause issues similar to the drive shaft. I wouldn't worry about a tire going flat and causing a catastrophic issue as you are explaining. NHRA's issue with parts hanging down is more a track condition issue. If you have a tire go down and parts hang lower than that, they would potentially dig into the track surface causing damage to the racing surface....

 

Very interesting stuff, cool to see people taking things to the extreme.

 

just some things to check out if your wanting to have some opshons

https://www.lefthanderchassis.com/v2...idcategory=389

http://www.speedwaymotors.com/AFCO-M...tes,26282.html

http://www.speedwaymotors.com/Deluxe...Kit,23683.html

http://www.speedwaymotors.com/AFCO-G...ets,23496.html

http://www.speedwaymotors.com/Panhar...d-On,3381.html

 

4 of the above links are for weld-on and for 3-3 1/2" axle housing tubes.
Mine were completely bolt-on for ease of changing/removing.