powdrhound

Here is just a heads up of a local track friend who installed some Elephant Racing lower control arms on the front of his street/DE track prepped Cayman. After 8400 miles of mixed street and track use, this is the result of a failure of the outer monoball trunnion pin.

Several years ago he installed OEM RSR LCAs in the rear of the car and chose to go with the Elephant LCAs in the front which resulted in a failure that caused significant damage to the front fender area as the wheel broke away from the suspension and the car went off track. He was very lucky this happened on turn exit as opposed to a 100+ mph sweeper where the results could have been substantially catastrophic and potentially deadly. The RSR arms on the rear of his car are going strong without failure to this day while the result of the Elephant arms installed on the lightly loaded front of the car are shown below.

To all my track peeps, be careful out there and don't skimp on quality parts especially when your neck depends on it. No matter what parts you use, set up a maintenance interval schedule that you're comfortable with and stick with it. Cheers!

Nickshu

Wow! I wonder if the nut came loose first. In theory shouldn't the taper hold it in place without much stress on the nut or threads?

Being as **** as I am I have rechecked torque specs on most of my suspension every so often. I have been surprised to find the ball joint nuts often loosen themselves slightly. Even with brand new nuts. I saw this on both my 6-C2 and my 6-GT3. Locktite is your friend on those nuts. I know it shouldn't be but that's been my experience.

powdrhound

The weakest part of the trunnion pin is the area at the base of the threads as that is the narrowest part of the pin and the start of the threads is a natural stress riser. This is precisely where the failure occurred in this case. The upper portion of the pin itself is in constant tension from the 56ft.lbs of torque imparted by the nut. Any minute amount of flexing can and will impart fatigue over time. Additionally, if the taper of the LCA trunnion pin is not precisely the same as the taper in the wheel carrier bushing then that will result in minute amount of flex. The loads that go through this area are tremendous.

Is is possible that the nut became loose? Sure. I personally do not use the factory nuts with the nylon locking feature as that is not very effective especially in an area near the hot brake rotors which will cause the nylon material to degrade over time and the nut loose it's ability to lock. I use the OEM "oval" self locking nut on all the LCAs and Toe arms and for extra safety also add a jam nut to prevent the main nut from working loose. You can see the jam nut arrangement here:

Sveach756

The jam nut is a simple and yet genius idea!
Shawn

Ahmet

I don't know if it's fair to call the front suspension lightly loaded, I would imagine they see tremendous load under braking, especially over bumps.

What is he doing for cooling, is the fender liner modified on that car?

Also, the ability to follow some of your build, and resulting insight is highly appreciated, here's a public thank you for sharing all this info!

tom03

To be honest that these third-party parts are not very reliable is not a secret. My front third-party drop link failed after 5 min...Afterwards I switched to OEM parts completely.
As powdrhound is saying use the secure and approved OEM parts if possible anything else is a risk. Saving money on one hand could be very expensive on some day.

mistermct

great PSA, thanks!

open question on the design: why does the pin narrow so much from the taper to threads? seems like an easy exercise to increase thread diameter and dramatically increase strength?

Atgani

Better still, if you need to upgrade these components, fit OEM Porsche Motorsport parts, they’ll most likely work out cheaper in the long run ...
Re-inventing the wheel is all well and good, but my experiences to date with these kind of “upgraded” suspension components have been less than satisfactory.
As the ER components on my car fail (specifically the custom/modified trunnions/bearings, seals, circlips) the whole component will end up in the scrap bin and be replaced with OE or Porsche Motorsports components.

JJT

It's scary to see that.

TKEES

Something I’m surprised nobody has mentioned here is the ball-joint and fastener manufacturer. Powdrhound mentioned the Hirschmann, the German OEM supplier, and my understanding is most US aftermarket Manufacturers all buy from the same US based supplier. These failures are not the direct manufacturing error of elephant, it’s not as though the LCA cracked in two. I think a lot of manufacturers try to manufacture to a high standard, the issue seems to be the supplier who seems to be the same across the board in the US aftermarket world.

Painting the aftermarket manufacturers as negligent or sub standard is an easy brush to paint the industry but even Powdrhound knows who the supplier responsible for these failures is. Elephant could buy different components but could be limited by their size and what could be high minimums from the German supplier of the molten vacuum steel components.

John should call out the supplier instead and take it easier on the guys who’s in house parts don’t seem to be at fault.

powdrhound

All components, whether OEM or aftermarket, are generally manufactured with some in house made parts along with a variety of vendor supplied parts (mono-*****, studs, or hardware for example) of various grades of quality. Some may be aerospace grade on one extreme and others may be Ace hardware grade on the other extreme with most falling somewhere in between.

As I’ve said 100x before, know the details behind the key components you are using and go with what gives you the warm and fuzzy. Most importantly, set up a maintenance / replacement schedule that fits your needs based upon YOUR use. By maintenance I mean checking parts for cracks, wear, proper torque, etc. By replacement I mean changing out parts after a certain amount of hours, cycles, etc. I’ve broken plenty of parts including OEM over the years and have adjusted my maintenance schedule accordingly. I replace axles for example on an annual basis or every 3000 miles. In some cases like wheel hubs I’ve gone to great lengths and expense to have custom components manufactured out of high strength metals like 300M to improve reliability and safety. I have always posted up my results as a heads up for guys to learn from and hopefully avoid the same pitfalls. Sharing the good and bad is a benefit to all when it comes to safety. Cheers...

Marv

That is just the polar extreme of blaming the manufacture (Elephant Racing in this case).

Generally, there is a middle ground here. COTS (commercial off-the-shelf) component variation may be the issue here, but the manufacture (Elephant Racing) also has a part to play in the game, too. They have to select the right vender and check incoming parts (at least a portion of the COTS parts) for compliance to their requirement specifications.

The problem is further compounded because we don't know...
1. how many of these parts actually fail. It could be a single failure or there could be many failures in the field,
2. conditions that the part failed or if a previous incident may have caused damage,
3. how it was installed (i.e., over torqued or something else).

The bottom line is we probably don't know enough to point to the root cause and because of that assigning blame is likely premature.

However, the general statement that Porsche Motorsports parts are superior to aftermarket components holds some weight, in my opinion.

KOAN

Superior is a relative term. I had PMNA drop links that bent pretty quickly. They were the size of BIC pens...really light weight, but probably a "wear item". The Tarett replacements have lasted much longer and are more sturdy, no problem whatsoever. So, in general, I agree that PMNA parts are very good, but one must consider their intended use and expected replacement schedule.

Atgani

That they bent would tend to suggest their orientation was sub optimal. Not sure why you’d buy PMNA (unless they’re the only homologated/legal parts you can use) or indeed any aftermarket drop links when you can buy all the necessary parts off the shelf.
Here in the UK we have these guys for turnbuckles :

http://www.mcgillmotorsport.com/metr...nkages-metric/

as as you can see, they’re cheap, strong and available in a variety of lengths. I’d be amazed if you can’t buy similar items in the US. Fit a set of the best quality German (Fluro) rod ends from Maryland Metrics :

https://mdmetric.com/rodend/fluro/motorsporthome.htm

and you’re good to go.

KOAN

I'm sorry I did not make my message more clear. My response was to the statement that

"However, the general statement that Porsche Motorsports parts are superior to aftermarket components holds some weight, in my opinion."

My example was to show that this statement is not necessarily true, and used PMNA drop links as an example.

As background, my PMNA drop links were installed by a shop that prepares factory supported Porsche race cars. After they bent, I was easily able to procure aftermarket (Tarett Engineering) drop links that were less expensive and more durable, as I stated in my post. Whether or not the orientation was suboptimal, in the many years and 10k track miles since the upgrade to Tarett parts, there has been no deformation of the drop links.

I am good to go.