control arm failure at the track this weekend

[DILYSI Dave]

Likely so. Mid-year '10 they went to a larger ball joint. So the arms aren't interchangeable before and from 08/03/2009 without swapping out ball joints.

So the early knuckles won't work with the later ball joint?

 

[STEVE_POE]

correct

 

[DILYSI Dave]

correct

Thanks. But the early and late ball joint will swap into either arm?

So what would be the best OE arm to use for making a spherical kit? 05-09 GT500? 11+ Arms (same for all models if I read correctly)?

 

[ZmanM3]

I'm thinking my BMR a-arms should be fine for the use they see on my car. I also need the extra clearance to keep the A-arms off my headers.

 

[STEVE_POE]

I'm thinking my BMR a-arms should be fine for the use they see on my car. I also need the extra clearance to keep the A-arms off my headers.

good luck with that

 

[07s281sc]

I've seen a similar failure once before on a 1999 cobra running the standard Griggs lower control arms which broke under heavy braking on the back straight at Limerock. Keep in mind the standard arms are no where nearly as beefy as the world challenge lcas.

 

[ocpony]

This is what I did after seeing Steve's post. So far these have held up to 3 Auto Cross events and the Optima Ultimate Street Car Challenge and have exceeded 1.3G loads. I will be giving them a full evaluation this season and check them after each event.

 

[jaguarking11]

Just one question. You guys are doing well over 1g load under hard braking and possibly turning while braking. The one thing that this brings to mind, its all fine and good to blame bmr or blame any company making these arms. However even if the arms did not fail, the ball joint holding onto the spindle is liable to break, I broke one last year in an accident, and they are not as beefy, which brings to the point, would you rather have the arm shit its pants like this and cause a relatively minor damage or a ball joint let go and cause the car to flip? You can chase your tail making a single component stronger and better, but you will soon find out that the next weak link will show its ugly head.

Also the steel arms on the s197 are designed almost like they are part spring, I am sure they flex severely under hard breaking. How long before someone breaks one of those due to work hardening?

Point being is that if you race, shit will break, its unfortunate but it will happen its a matter of when. Nothing against this argument, failures should not occur however racing is racing and they will occur. Every racer knows that if they don't want to pay someone to develop parts for them they will have to develop their own.

If you want minimum compromise, scan the stock A-arm, enlarge it about 10% and c&c it out of billet, hard anodize it and bolt it on. Personally I would look at adapting a much larger lower ball joint while im at it, something out of say an f350 or comparable large vehicle. The total will be something much stronger, however the weight savings would be much smaller.

 

[ArizonaGT]

If you want minimum compromise, scan the stock A-arm, enlarge it about 10% and c&c it out of billet, hard anodize it and bolt it on. Personally I would look at adapting a much larger lower ball joint while im at it, something out of say an f350 or comparable large vehicle. The total will be something much stronger, however the weight savings would be much smaller.

 

[ocpony]

jauguarking,

I installed the balljoints myself into the A-Arms and I can tell you they are much stronger pieces than the stock ball joints. Also, I will bet they would never come out of the A-arm either since it maxed my 20 ton press when I installed them. I actually had to ream the hole slightly to get them to press in and had the ball joints near freezing temps to help shrink them.

Breaking parts is part of racing. If you aren't breaking something you aren't driving hard enough. Anytime you try to improve parts and make them lighter then you increase the risk of breakage. I like to always be able to finish races or events so I mod parts and test them as much as possible before major events. We always hope for the best and plan for the worst. This is why safety equipment is important and why I double and triple check everything before races especially on mods to critical components. I try to provide the community my results since many on here do the same and I benefit and well as everyone else does to help further the sport.

 

[STEVE_POE]

All my ball joints are tack welded after install.

 

[jymontoya]

All my ball joints are tack welded after install.

Good to know!!

 

[ocpony]

Poe,

That is good idea and wish I had thought to do it with mine just to be extra safe. Since I installed them though I am very confident they aren't coming out though as tight as they were. It is my own butt I have to protect so I do everything I can to be as safe as possible. Since I was modifying the arm already it would have been simple to tack them before the paint though. Will do it on the next ones I make.

Here is a shot of it on the car finished.

 

[jaguarking11]

jauguarking,

I installed the balljoints myself into the A-Arms and I can tell you they are much stronger pieces than the stock ball joints. Also, I will bet they would never come out of the A-arm either since it maxed my 20 ton press when I installed them. I actually had to ream the hole slightly to get them to press in and had the ball joints near freezing temps to help shrink them.

Breaking parts is part of racing. If you aren't breaking something you aren't driving hard enough. Anytime you try to improve parts and make them lighter then you increase the risk of breakage. I like to always be able to finish races or events so I mod parts and test them as much as possible before major events. We always hope for the best and plan for the worst. This is why safety equipment is important and why I double and triple check everything before races especially on mods to critical components. I try to provide the community my results since many on here do the same and I benefit and well as everyone else does to help further the sport.

My old car was totaled last year on black Friday. The first thing that broke was the ball joint, it was not about to break where the ball-joint was mounted, the actual spigot broke. Made me think the factory one is not beefy enough. I think a few mil thicker plus reaming the lower mounting hole on the bottom of the upright would make a world of a difference, again the moment you make something stronger all you do is show the next weakest link, eventually I would think the weak link would be fracturing the mount points on the k member or flexing the shock towers and warping them.

 

[jaguarking11]

WTF is that supposed to mean? I am a bit thick in the head sometimes. Don't quite understand......

 

[SoundGuyDave]

CNC= Computer Numerical Control, used in manufacturing, particularly in milling operations.

C&C Music Factory is a bad band from the late 80's... ;-)

 

[knownukes]

is bad good or is bad bad? LOL

 

[ArizonaGT]

CNC= Computer Numerical Control, used in manufacturing, particularly in milling operations.

C&C Music Factory is a bad band from the late 80's... ;-)

 

[pcdrj]

CNC machine shop tour



http://www.facebook.com/pages/DR-Machine-Company/346440642034617?ref=hl

 

[Sam Strano]

I've seen aftermarket front lower arms fail on a number of cars, from a number of companies. And in a number of places (street only, autox, track). Some have lasted years, some less than a week.

You are taking your chances with that stuff. I won't sell them for this car, and I don't like to sell them for others. In fact when I do Camaro work, I only recommend one particular boxed set from one company if the person is inclined to change arms.

ocpony. If you say 1.3 g, it was not a true force.. helped by a bump or a dip, or banking. I can't pull 1.3 on Hoosier's in a true steady state situation, let alone doing that on a 200 TW street tire. I'd be very curious how that was measured, because we use things like Traqmate systems with both GPS positioning (which reads speed and corner radius, and 3 axis accelerometers both). We use this because the accelerometer alone can be fooled by banking. It sees more "roll" and that throws off the number you see. Granted banking does add grip, but 1.3 on banking is different than a true 1.3 lateral. I've seen numbers in banking and dips over 1.6, but the car can't pull a true 1.6 even on race tires. The forces involved, while high, are not nearly what you'd see a car on R-compounds put through. And remember that we've seen arms (more than a few) break just plain old street driving.