Having a aftermarket control arm is not a hugh deal for me. BUT if I was going to because of the history of what we have had for our cars. I would want to see alot of testing. one night on the track is not enough. Lots of track and lots of street driving.
I do know a guy in Florida with a set of RK Sport arms (the newer design). He has been using them for a long time no issues.
FU Tuning
OEM wrote:Umm, what? I explained in teh above post that the ball joint is moved lower, making the roll center of the wheel/ suspension correct again.
Umm, what? I don't see that mentioned in any of your posts in this thread? I'm not known as being super-observant, but even ctrl+F has failed me here...
Also, what do you mean by "moving the ball joint lower"? Lower relative to what? By what amount? How did you determine the proper amount?
Looking at MD's pictures, I'm lead to believe that maybe they were welded too 'hot'. Having a failure
right at the end of the welded gusset is a sign of that. Also, I'm skeptical of the gusset size being the issue because the fracture doesn't look like the result of bending stresses on that bar (frontal wheel loading, would be marked by metal elongation on the engine side, and possibly chips on the outward side).
fortune cookie say: better a delay than a disaster
Question for ya. Just a thought. Would it be possible to raise the location of the balljoint? Reason I ask is because with my almost 3 inch drop, the control arms are angled up pretty badly. In theory, raising the ball joint location might help wthis a bit. Would it be possible?
OEM wrote:OEM wrote:Well as you know if you lower your car you change the roll center of the suspension. On a j-body its not that bad but if you go to low it will really start to hurt your suspension in terms of working correctly to get better handling. We just finished up a set of arms for a B13/B14 Nissan. Take a look and please let us know your though. Price would be $450 and would need 5 people to make it happen. Time would be around 1 month.
There you go. Roll center being offset by the lowering of a car. I guess I did not make it super clear but it was there.
I saw that (obvioulsy, I quoted it after all). I'm wondering about this:
OEM wrote:Umm, what? I explained in teh above post that the ball joint is moved lower, making the roll center of the wheel/ suspension correct again.
(in bold)
You made it sound like you had previously mentioned relocating the ball joint. Just a mis-understanding.
OEM wrote:It does look like the gusset was the problem. There was not enough load transfer with the gusset.
What type of loading? Applied where and how? There are many things about that break that I am curious about, and I've always enjoyed failure analysis
OEM wrote:The gusset should be substantial, and should be 1/4" or thicker. Its no doubt in my mind that the gusset was the problem.
Well, that would depend on many many variables which are not known to us. Do you have FEA or even basic hand calcs to support your theory? Although throwing a 12" diagonal 1/2" thick gusset on it would probably prevent the failure, I think at least
some optimization would be grealty beneficial, overkill or not.
OEM wrote:I can not say for sure that the weld was the problem as I can not get a good look at the weld. It looks like it was MIG welded, which is ok if done right. We TIG all of our stuff, so its a much cleaner weld and penetrates much more.
I'm not sure how that is relevant to what I was referencing, but okay...
OEM wrote:Now you are asking about the ball joint location. If you have a lowered car, go look underneath it and look at the arm, I bet its got a pretty good arc to it. What the relocation does it moves the ball joint back down to factory spec so it will handle better.
Not very clear, but it seems you are talking about the arms passing the ground-horizontal as the vehicle is lowered large amounts? If you're looking at spacing the ball joint off of the knuckle, that wouldn't necessarilly require new arms, just a weird-ass spacer. Even then, what do you mean by "factory specs"? The arm angle? You probably wouldn't want that at factory specs now that the vehicle has been lowered? If you're talking abour the roll couple, that sucks from the factory, dialing in some more oversteer would be helpfull for pretty much anyone who would buy these...
fortune cookie say: better a delay than a disaster
Screaming for Mercy!! wrote:Having a aftermarket control arm is not a hugh deal for me. BUT if I was going to because of the history of what we have had for our cars. I would want to see alot of testing. one night on the track is not enough. Lots of track and lots of street driving.
I do know a guy in Florida with a set of RK Sport arms (the newer design). He has been using them for a long time no issues.
If I remember correctly, the redesigned RK arms where made from rectangular tube
Jason
99 Z24 Supercharged
157hp/171tq - NA
190hp/170tq @ 6psi
LG0/LD9 for Life
OHV notec wrote:z yaaaa wrote:id like to see something done up in aluminum (as always mark 
)
There's a good reason tubular arms are usually chromoly instead of aluminum...
tell that to all the car that use strong arm upper's AND lower's on tons of muscle car builds around the country please.
180hp in 1989 or 145hp in 2002, you decide. >
z yaaaa wrote:OHV notec wrote:z yaaaa wrote:id like to see something done up in aluminum (as always mark )
There's a good reason tubular arms are usually chromoly instead of aluminum...
tell that to all the car that use strong arm upper's AND lower's on tons of muscle car builds around the country please.
Oh good lord... Important part in bold... Why not make them out of carbon fiber, all the Formula cars have been doing it for years!
Yes, 6061-T6 has almost 1/3 the density of 4130, but the 4130 has up to 5x the fatigue strength, and is 3x stiffer. Add the significantly reduced cost, and I'll take chromoly on a street car any day of the week. Also, aluminum outgasses when powdercoating, so many coaters may charge extra since it often needs to be pre-heated while spraying (might not be an issue with control arms since they're so thin, but I always do it anyway just to be safe).
I have a vehicle in the shop with a torn 1/4" thick tube on a 6061-T6 trailing arm. And that used nylon bushings to dampen vibrations, a significant advantage to spherical bearings when fatigue is a primary factor...
fortune cookie say: better a delay than a disaster
OHV notec wrote:z yaaaa wrote:OHV notec wrote:z yaaaa wrote:id like to see something done up in aluminum (as always mark )
There's a good reason tubular arms are usually chromoly instead of aluminum...
tell that to all the car that use strong arm upper's AND lower's on tons of muscle car builds around the country please.
Oh good lord... Important part in bold... Why not make them out of carbon fiber, all the Formula cars have been doing it for years!
Yes, 6061-T6 has almost 1/3 the density of 4130, but the 4130 has up to 5x the fatigue strength, and is 3x stiffer. Add the significantly reduced cost, and I'll take chromoly on a street car any day of the week. Also, aluminum outgasses when powdercoating, so many coaters may charge extra since it often needs to be pre-heated while spraying (might not be an issue with control arms since they're so thin, but I always do it anyway just to be safe).
I have a vehicle in the shop with a torn 1/4" thick tube on a 6061-T6 trailing arm. And that used nylon bushings to dampen vibrations, a significant advantage to spherical bearings when fatigue is a primary factor...
Really? I know you were just trying to make a point but seriously? Carbon fiber can not be used on a control arm as the weave only has structure one way, the way the weave is going. You show me a full cf control arm and I will apologize but for right now I doubt you very much.
No again. Even though its cheaper, DOM chrome molly tubing is about the same in Prime stock as aluminum and weights 3 times more.Generally aluminum and steel are the same price as they have there advantages and disadvantages. One weights more one cost more but it equals out.
Not sure who is doing your PC but there ripping you off if they charge you more and give you that load of crap.
Again, NO. If you have nylon bushings your dumb. Nylon is no good for bushings, they need to be delrin or poly or the factory rubber. Nylon is hygroscopic, meaning it takes on water. if you have them in your car I feel bad for you.
Mark
http://www.overkillengineeringmotorsports.com/
its super funny all the time watching people talk about things they dont know a whole lot about. Im not saying anyone inparticular, just people.
Mark, there are control arms and a lot more made from 100% CF. The speedbrake door on the U2 aircraft is 100% carbon fiber.
Weaves can be rotated to give desired effects.
Mark, the idea is good for control arms, but with the aluminum ones easily available, I think it might be something that not to many are interested in.
OEM wrote:OHV notec wrote:z yaaaa wrote:OHV notec wrote:z yaaaa wrote:id like to see something done up in aluminum (as always mark )
There's a good reason tubular arms are usually chromoly instead of aluminum...
tell that to all the car that use strong arm upper's AND lower's on tons of muscle car builds around the country please.
Oh good lord... Important part in bold... Why not make them out of carbon fiber, all the Formula cars have been doing it for years!
Yes, 6061-T6 has almost 1/3 the density of 4130, but the 4130 has up to 5x the fatigue strength, and is 3x stiffer. Add the significantly reduced cost, and I'll take chromoly on a street car any day of the week. Also, aluminum outgasses when powdercoating, so many coaters may charge extra since it often needs to be pre-heated while spraying (might not be an issue with control arms since they're so thin, but I always do it anyway just to be safe).
I have a vehicle in the shop with a torn 1/4" thick tube on a 6061-T6 trailing arm. And that used nylon bushings to dampen vibrations, a significant advantage to spherical bearings when fatigue is a primary factor...
Really? I know you were just trying to make a point but seriously? Carbon fiber can not be used on a control arm as the weave only has structure one way, the way the weave is going. You show me a full cf control arm and I will apologize but for right now I doubt you very much.
Like you said, I was just making a point, but... Carbon components are
engineered with multiple layers when necessary. I've even taken a course, lead by a Boeing rotor designer, on composite design and manufacturing. Changing how the layers are oriented to eachother changes the overall strength in the different planes. Next time I'm at the shop I'll see if they have one of the arms for our Formula car done...
OEM wrote:No again. Even though its cheaper, DOM chrome molly tubing is about the same in Prime stock as aluminum and weights 3 times more.Generally aluminum and steel are the same price as they have there advantages and disadvantages. One weights more one cost more but it equals out.
When buying a given cross-section, this is true (steel weighs more, but costs less/#). However, the arm can use a thinner wall when using chromoly, reducing the overall cost.
OEM wrote:Not sure who is doing your PC but there ripping you off if they charge you more and give you that load of crap.
Well, I do my own PC, so this is from experience. Out-gassing is legit, and I've personally had to deal with it (scared the hell out of me the first time). I usually only coat aluminum in the summer (here in Phoenix, all I have to do is coat it outside and the sun will pre-heat it to 100F+ lol). However, when I have to do it in the winter, I have to pay for that little extra bit of electricity to pre-heat. It's not much, but the cost is there. Whether your guy charges or not I wouldn't know; but like I said, doing thinner materials (I believe everything you fab would fall in this relative category), it may not be necessary. I wasn't saying this would be a major point in this discussion, just for overall materials selection considerations.
OEM wrote:Again, NO. If you have nylon bushings your dumb. Nylon is no good for bushings, they need to be delrin or poly or the factory rubber. Nylon is hygroscopic, meaning it takes on water. if you have them in your car I feel bad for you.
Well, I didn't personally choose the material here; I just know it's a relatively stiff polymer. I did the front arms, 4130 and Heim joints, made it through hell and back.
fortune cookie say: better a delay than a disaster
Hold on let me guess, your in school for engineering? I am guessing 1 or 2nd year? By the way you talk it seems it.
Chris, were not talking about airplanes here. I do understand that CF is used in many different applications, I was merely looking for an example.
You guys always seem to blow @!#$ up to something it does not need to be. I was asking for people that were interested. Then it goes all out of hand with CF arms and powder coating.
Edited 1 time(s). Last edited Friday, July 23, 2010 1:30 PM
http://www.overkillengineeringmotorsports.com/
Here is our comment to FMEA, one of our guys had to deal with a person on an SR forum about this, here was our explanation. Hope its clear enough.
Mark-OEM
Originally Posted by mevans View Post
How about some more testing i.e. FMEA and fatigue before this product is available. I applaud your design efforts but these are critical suspension components we are talking about now.
You must work for an ISO company?? FMEA's used to be my life in my last job.
Here at OEM we do our own Failure Mode Effects Analysis. We analyze the product and all of its potential failures, then we take it to the next level and reinforce. We have taken many steps to increase performance (weight gains) and safety considerations.
Quote:
Originally Posted by wnwright View Post
Uhm No
Usually when the arm fails the force after failure on the other parts which are no longer supported also have a tendency to fail (especially tie rods and sway bar mounts (depending on where failure point is)... strut is stronger, but can rip out if upper hat isn't supported). I find it VERY hard to believe you would have a situation where it would just "cave in and wobble". Usually the failure will rip the wheel off or rip it sideways and throw the car out of control. Failure is a BIG deal.
Not saying your design will fail, but failure is a big deal if it does happen. I do question anything where you are able to take a structural member and reduce 10lbs out of it. Based on that I have to suspect the margin of safety has been reduced. Typically tubular arms are able to take a couple of pounds when compared to stamped arms with no reduction in margin.
To be honest things could happen ... just like a Prius, or BP you can design a product, test it and it could still have a problem that you could have never imagined.
We have been building quality, well built, strong products for a while now.
If you have questions about integrity please ask and we will do our best to explain the steps taken to reduce their effects to as close to zero as possible.
The arm uses superior materials, superior welds and superior additions such as the rod ends and the delrin bushings. The arm has been reinforces using .25" plate, plasma cut to conform to the arm dimensions thus leaving less of a gap and more contact for reinforcement and unlike conventional tubular arms we have taken into account failure points with reinforced "soild" construction.
- Brian - OEM
__________________
http://www.overkillengineeringmotorsports.com/
OEM wrote:EvoFire wrote:its super funny all the time watching people talk about things they dont know a whole lot about. Im not saying anyone inparticular, just people.
Mark, there are control arms and a lot more made from 100% CF. The speedbrake door on the U2 aircraft is 100% carbon fiber.
Weaves can be rotated to give desired effects.
Mark, the idea is good for control arms, but with the aluminum ones easily available, I think it might be something that not to many are interested in.
Your awesome.
mark
did that strike a nerve or something? it wasnt directed at you, but if it hit you hard maybe you need to take a look in the mirror.
EvoFire wrote:OEM wrote:EvoFire wrote:its super funny all the time watching people talk about things they dont know a whole lot about. Im not saying anyone inparticular, just people.
Mark, there are control arms and a lot more made from 100% CF. The speedbrake door on the U2 aircraft is 100% carbon fiber.
Weaves can be rotated to give desired effects.
Mark, the idea is good for control arms, but with the aluminum ones easily available, I think it might be something that not to many are interested in.
Your awesome.
mark
did that strike a nerve or something? it wasnt directed at you, but if it hit you hard maybe you need to take a look in the mirror.
Didnt think it was, but I know I am awesome lol, how about u?
http://www.overkillengineeringmotorsports.com/
OEM wrote:Hold on let me guess, your in school for engineering? I am guessing 1 or 2nd year? By the way you talk it seems it.
Nice try at a dodge there. I mention taking a class and suddenly you try to refute everything that has been said by attacking the person instead of the message. I have only been offering constructive criticism so far, not belittling you or your products.
I did 6 years, and the mentioned class was a graduate course.
OEM wrote:Chris, were not talking about airplanes here. I do understand that CF is used in many different applications, I was merely looking for an example.
Actually, you said that CF couldn't be used for a control arm, and used false reasoning. I corrected your false reasoning, provided my reasoning, and you started flaming. Yeah, you're awesome.
OEM wrote:You guys always seem to blow @!#$ up to something it does not need to be. I was asking for people that were interested. Then it goes all out of hand with CF arms and powder coating.
Sad, seeing as I was just trying to get more details on the product... No joke, I was considering fronting the $$$ as one of the five needed, I just wanted a simple elaboration. The CF, as you acknowledged, was just to make a quick point, not a serious suggestion. CF arms on a street car would be a horrible idea; maybe someday JBO will have a *SARCASM* smiley?
fortune cookie say: better a delay than a disaster
I'd be interested.
for the skwirl especially, but I wouldn't mind a set for my 04 when I re-lower it.
Listening/ subscribed for interest only.
Good luck with this Mark.
Misnblu.com
Newbie member since 1999
Thank you Dave and JBO! 
you can see the weave in the lower arms , also helps to enlarge the pic
