Poly Bushing Failure at Road Atlanta

[Flyboygsxr]

I was at Road Atlanta this last weekend in the Boss for a track day. To give you a little background you can see all the mods I have in my signature. On this particular weekend I decided to go with the stock Pirelli's and pads since it was pretty cold out and I didn't to bother with changing brakes and wheels…I even drove the car to the track. I don't hardly use the stock Pirellis and being that they are 3 years old and it was 40 degrees out the traction was nothing impressive. On my 4th session the poly bushing in my Steeda adjustable UCA failed while coming into turn 6. I was hard on the brakes and the car out of no where kicked sideways and some wild axle hop ensued while I was sideways I might add. I came back into the pits and the problem was apparent as half of the bushing had come out the side and was only hanging on by a small piece still attached. I was still able to limp the car home without causing any damage but this is the 3rd poly bushing in these steeda control arms that has failed on me. Steeda sent me a complimentary package of replacement bushings after the first one failed also causing the car to go slightly sideways on a previous track day. Though the first time it was the lower control army and it wasn't anything dramatic. I could just tell the rear was out of alignment. I still have some replacement bushings left over but I have lost faith in poly control arms. Has anyone else had their bushings fail on them? I very very rarely ever drive this car on the street. I trailer it to 90% of my events and run the car pretty hard and pull some descent lap times. I don't know if this should be considered regular track maintenance? I would say the bushings will last me for a season which usually consists of about 10-12 track days. If you skip ahead to the 9:50 mark in the video you can see what happens.

Adam

https://www.youtube.com/watch?v=1Xvz8tm33PA&feature=youtu.be

 

[VoodooBoss]

Whoa I'm sure that got your attention. Glad you didn't lose it.

 

[Flyboygsxr]

You can't tell in the video but the slip angle was about 20 degrees…Could have been bad if that happened going into 10a at 140mph.

 

[Grant 302]

Adam-

Thanks for sharing. Glad you're safe and that there wasn't any vehicle damage resulting from the failure. 8)

I've been only a little vocal about the reasons why I wouldn't use or recommend poly in the rear control arms for handling applications, and this just reinforces my suspicions and concerns. The primary reason to me is binding, and that binding leads to failures from the bushing squirm. Poly bushings just aren't made to twist as needed. The exception, to me would be the ball-insert poly joints like J&M uses.

I hope this causes some to reconsider their use. Or at least to consider them a very regular maintenance/replacement item in handling applications.

@Brandon302
@BMRTech

 

[Flyboygsxr]

Another BMO member, JD, was right behind me filming when this happened so hopefully I can share that video soon and you can see from the outside perspective what it looked like.

Adam

 

[302 Hi Pro]

Adam:

That was a nice recovery. I enjoyed watching your video and liked your shift points and RPM levels through the turns. I also noticed you were picking up the pace of your laps, between the 6 and 7 minute mark, just a few laps prior to failure.

I too run a 12 Boss with the same UCA, so your post had my attention! Prior to this, I haven't read of this failure before, but after watching your video and reading about the service life of your Poly bush, I would think this should be considered a maintenance item and changed out during your pre-season inspection.

You're a good driver and considering that you rarely Street your Boss, why don't you purchase the Steeda competition upgrade for your UCA? I run the joins In my set up with the exception of the UCA and NVH is not that bad in my case.

OBTW, While you're there, (UCA location), you should inspect the upper Axle Housing bush. I found mine was worn badly and replaced it last summer when I installed the UCA.

Good luck with your 2015 season,
Dave
302 Hi Pro

 

[Flyboygsxr]

I actually have the Steeda spherical bearing UCA in my garage. I took it out and replaced it with the poly arm last year because the rattling was really annoying. I think the tolerances aren't as tight as they were when it was new which caused the development of the rattle. I don't mind the increased NVH at all but that rattle got annoying. I am definitely going to switch back though for piece of mind.

Adam

PS…It took me a while to develop any confidence in the stock Pirelli's. A combination of the tires being 3 years old, the cold temperatures, and Road Atlanta likes to eat cars for lunch made me take it a little easier. Watch out for turn 7 and especially because two cars blew their engines dumping oil all over the track. You can see the black oil spots in the video on turn 1 and 7.

 

[DGRacing]

I actually have the Steeda spherical bearing UCA in my garage. I took it out and replaced it with the poly arm last year because the rattling was really annoying. I think the tolerances aren't as tight as they were when it was new which caused the development of the rattle. I don't mind the increased NVH at all but that rattle got annoying. I am definitely going to switch back though for piece of mind.

Adam

PS…It took me a while to develop any confidence in the stock Pirelli's. A combination of the tires being 3 years old, the cold temperatures, and Road Atlanta likes to eat cars for lunch made me take it a little easier. Watch out for turn 7 and especially because two cars blew their engines dumping oil all over the track. You can see the black oil spots in the video on turn 1 and 7.

Adam, just do a cat delete and put the side pipes on. The annoying rattling goes away! You drive your car too hard for poly bushings man.

 

[BMRTech]

First and foremost, I glad to see you came out with no injuries. Also glad to see the car is okay!

I definitely agree with the above. I highly recommend bearings of some sort, when tracking these cars. Both on course, and at a drag strip.

Poly bushings are good for the average Joe, who likes better performance from their vehicle....but IMO, they do not belong on tracks.

As for the Poly on the UCA, we do realize that the majority of our customers use Poly. So, on our Poly 11+ UCA...we engineered it to allow for slightly more articulation than most others designs. The downfall is, when you design a poly bushing to articulate, you give up raw strength for the straight line guys, who are the majority of the suspension market.

Great advice was given above...about the axle diff bushing. Those pieces fail everyday. I would recommend a dual durometer Poly piece, or a bearing up there.

On that note, I highly recommend checking out our new "Ultimate" UCA. I really like the Multimatic UCA....so I designed the 033 with that part in mind, but went even further with it - making it the absolute best UCA money can buy for an S197.

 

[BOSSSTANG]

Just curious, what UCA mount are you using with the Steeda?

 

[2012-Boss]

First and foremost, I glad to see you came out with no injuries. Also glad to see the car is okay!

I definitely agree with the above. I highly recommend bearings of some sort, when tracking these cars. Both on course, and at a drag strip.

Poly bushings are good for the average Joe, who likes better performance from their vehicle....but IMO, they do not belong on tracks.

As for the Poly on the UCA, we do realize that the majority of our customers use Poly. So, on our Poly 11+ UCA...we engineered it to allow for slightly more articulation than most others designs. The downfall is, when you design a poly bushing to articulate, you give up raw strength for the straight line guys, who are the majority of the suspension market.

Great advice was given above...about the axle diff bushing. Those pieces fail everyday. I would recommend a dual durometer Poly piece, or a bearing up there.

On that note, I highly recommend checking out our new "Ultimate" UCA. I really like the Multimatic UCA....so I designed the 033 with that part in mind, but went even further with it - making it the absolute best UCA money can buy for an S197.

Would you clarify this a little? My understanding is that you / BMR recommends using UTCA033 spherical bearing upper control arm with your EN001 multi-piece polyurethane differential bushing even for road racing, correct? Is there a downside to this combination?

What would be the benefits and drawbacks with combining the UTCA033 UCA with a spherical bearing in the differential similar to the Steeda 555-4104 differential bearing?

 

[BigTaco]

I'm glad the OP was able to get through this ok. That would have required both a bushing and underwear upgrade if it were me. This incident is a good reminder to us all that poly bushings are a wear item and should be inspected/replaced regularly; Even more so for cars that are tracked, just like wheel hubs, brakes, fluids....
Under high load, high performance situation, all wear is accelerated.

I think that we all sometimes suffer from a "install and forget" mentality when it comes to high performance items. I now buy extras (bushings, fasteners, filters...) as part of the purchase.

 

[Swiss Boss]

I have the BMR UTCA033 on my car for a year now (8-10 track days). That thing is a beast, very happy with it.

There is more whine from the diff, mostly between 65-75MPH, but there is no clunk at all.
I still have the stock bushing in the diff housing. I'm too lazy to change it yet.

The problem with spherical bearing on both side, is that the arm is "free" to rotate by himself and come touch body part which will make all kind of loud noise. Other than that I don't think there is a problem.

 

[2012-Boss]

I have the BMR UTCA033 on my car for a year now (8-10 track days). That thing is a beast, very happy with it.

There is more whine from the diff, mostly between 65-75MPH, but there is no clunk at all.
I still have the stock bushing in the diff housing. I'm too lazy to change it yet.

The problem with spherical bearing on both side, is that the arm is "free" to rotate by himself and come touch body part which will make all kind of loud noise. Other than that I don't think there is a problem.

Kelly at BMR and I had a conversation about this several weeks back. I was hoping BMR will elaborate on the subject so people hear it straight from the horses mouth.

Kelly was very specific about not using a dual bearing combination with the BMR arm because it would result in clunking. I am not sure what the recommendation is for a track only car.

When I replaced my UCA, I found that my differential bushing had failed which is a very common problem.

 

[Swiss Boss]

Kelly at BMR and I had a conversation about this several weeks back. I was hoping BMR will elaborate on the subject so people hear it straight from the horses mouth.

Kelly was very specific about not using a dual bearing combination with the BMR arm because it would result in clunking. I am not sure what the recommendation is for a track only car.

When I replaced my UCA, I found that my differential bushing had failed which is a very common problem.

My diff bushing is still fine but knowing my luck it will fail on my first track day.

There someone over in S197 that runs both and he said that it is very clunky. I'm not sure if you can tell the difference between a spherical bearing or a poly one performance wise.

I don't mind whine or squeaky noise but I hate clunk because you never know if it's from the part that supposed to clunk or if it's from something different that is failing.

 

[steveespo]

I run Steeda arm with Spherical bearing and the Steeda differential spherical bearing and I can confirm it clunks. The rear axle is also free to articulate and has minimal fore/aft play. Since I only track the car the noise is not an issue, for the street it would drive you crazy. Track use demands frequent suspension inspection, don't check the tech form if you don't check the parts.
Steve

 

[Flyboygsxr]

Just curious, what UCA mount are you using with the Steeda?

I am using the steeda adjustable UCA mount.

 

[cloud9]

I run Steeda arm with Spherical bearing and the Steeda differential spherical bearing and I can confirm it clunks. The rear axle is also free to articulate and has minimal fore/aft play. Since I only track the car the noise is not an issue, for the street it would drive you crazy. Track use demands frequent suspension inspection, don't check the tech form if you don't check the parts.
Steve

+1. Funny thing is I considered swapping to poly bushings this year because the clunking on the streets does drive me crazy......this reinforces my decision to stick with the spherical bearings on the UCA.

 

[DGRacing]

The clunk is indeed alarming. I always tell people my car drives like a rusty battleship around the paddock (and it does. creaking, clunking, rattling; inside the tincan loudspeaker called the interior) but at speed its a graceful gazelle and puts big smiles on my face. Leaving behind driver comfort for performance was a difficult and ponderous transition (but necessary). :-[

 

[Flyboygsxr]

Here is a link to the control arm I took out because I didn't like the clunk but now will be putting back in.

http://www.steeda.com/steeda-mustang-adjustable-control-arm-555-4113/