Why I never had much confidence in Kenny Brown parts

[ac427cobra]

What is your setup in the rear now Bruce?

Skeet:

I have the KB IRS with coil-overs and notched frame rails. I'm pretty happy with how it functions but if I would have known what I had to go through to install it I would not have bothered! Trust me!! My previous IRS set up with the Delrin/UHMW/Aluminum (we're now selling) worked pretty damn good!!

:thumbsup: :coolman: :beer:

 

[thomas_moran]

Hey Bruce! Man that's lame... As someone who's broken 2 KB rear upper control arms I can relate to what your felling. When we were dealing with Kenny Brown we had very positive experiences. When the first control arm broke (we were one of the first to run them is what they told us) we contacted them and they made new upper arms for us out of Chrome Moly. The first ones were mild steel and broke after about 3 events or so.

The second arm broke the first time we went to CMP 3 years ago... It turned out that when they made the new arms for us out of Chrome Moly the piece of metal tubing that the bushing sits in was ERW tubing... Huge screw up on their part... The cool thing was that when we got home from CMP there was a message from Brad at Kenny Brown on our machine telling us that they heard through the grape vine about what happened to us and that a new part was already being shipped to us and it was all free. Brad was the only guy we ever dealt with so I can't speak for the whole company but that guy knew how to take care of customers...

On the topic of the KB IRS as a whole I think it works pretty good once you get it all sorted out. IMO the IRS in the cobra was a compromised design to begin with and Kenny did his best to make it work. Kenny seemed to be the only one to really work with the IRS and get it right. Everyone else in the market place seems to think it sucks so much they didn't want to spend time developing parts and tell people to put a stick axle in their car. Its cool to see guys like Mark and Tone proving that an IRS can and will work really well if its sorted right.

Keep in mind that as much as we all love to pound around the track in our mustangs they aren't purpose built race cars and stuff is going to break no matter whats on them.

Now that Kenny seems to be out of business we're in the same boat as you if anything breaks. Our plan if a control arm snaps is to build new ones ourselves using the old one as a template and making it stronger. Luckily our cage builder is good friends with a guy who used to design suspensions for British touring cars so we should be in good hands if anything ever breaks.

Maybe we should consider starting a support group for people with KB IRS

Just my 2 cents...

 

[Cobra-R]

I'll admit there were cars at every event that were faster than me, some way faster. I was never on track with these cars because they would be driving in red group, advanced group, instructor group, whatever. Do you think Bruce's car is fast. It seems that he has everyone's respect on this board including me, And I have synced up one of my VIR videos with his video he made in I believe November when temps must have been much more favorable than the 95 degree temps when my video was made and I am at 2:17 to his 2:14. you don't have to believe this, it just is. Like I said, this is mostly a testament to Kenny's parts because as you know someone with the little bit of track time I have could not possibly be the reason. :nono:

Having more information deffinately starts putting things into perspective, but judging a suspension system against other cars driven by inexperienced drivers is hardly conclusive.

Yes, I agree bruce is fast, but again it is all relative. Pure lap time doesn't mean alot to me. There are many drivers in here that are as good as bruce but not turning the same lap times due to other reasons, like hp, weight, tires, ect.

I havn't been to VIR, but isn't that more of a HP track than a handling track?

Brian

 

[NJ2000R]

I wonder if anyone owns the rights (patents?) to the kb designed parts? if they are not coming back as a company, I'd imagine there would be some sort of a market for the items they sold, particularly the IRS stuff, since nobody else has anything to offer....maybe someone will take what they have and shop it around to be produced? my opinion is that while they created some decent stuff from a design standpoint, they did have some deficiencies in quality....I had to alter their extreme matrix braces to get them to fit, as one was too short and the other too long....I guess we'll have to wait and see what happens....

 

[Exit Speed]

Having more information deffinately starts putting things into perspective, but judging a suspension system against other cars driven by inexperienced drivers is hardly conclusive.

Yes, I agree bruce is fast, but again it is all relative. Pure lap time doesn't mean alot to me. There are many drivers in here that are as good as bruce but not turning the same lap times due to other reasons, like hp, weight, tires, ect.

I havn't been to VIR, but isn't that more of a HP track than a handling track?

Brian

Hey Brian, I have really learned since being exposed to open tracking, starting with Mountaineer Madness last year, that there is a huge gap in what shows up for DE's in cars and drivers. Unfortunately I spent most of my lapping in intermediate groups getting seat time. I spent I lot of time following slower traffic. I am really looking forward to getting into advanced groups this year when allowed, to start building more speed and adjusting lines. I can tell there is a wealth of skill, experience, and knowledge, on this board. Ken has agreed to help me at Summit this year and Bruce if he makes it to VIR this November. Having said all that I still am Impressed with the way the snake works. I had an instructor go out with me late last year to sign me off to run in the advanced group and he said he had never ridden in Mustang that well sorted. Thanks everyone for sharing what you know. Peace, Skeet.

 

[ac427cobra]

When we were dealing with Kenny Brown we had very positive experiences.

Thomas:

I do not doubt you for a second! I'm glad you were happy with them and they treated you well! I can't say the same thing unfortunately.

Maybe tonight I will post some more pics of "colored gossy photos with circles and arrows and a paragraph on the back of each one" and try to condense my entire IRS History into a short novel, but I digress!!

Too bad my story is not as funny as Alice's Restaurant! :cryying:

 

[Cobra-R]

Hey Brian, I have really learned since being exposed to open tracking, starting with Mountaineer Madness last year, that there is a huge gap in what shows up for DE's in cars and drivers. Unfortunately I spent most of my lapping in intermediate groups getting seat time. I spent I lot of time following slower traffic. I am really looking forward to getting into advanced groups this year when allowed, to start building more speed and adjusting lines. I can tell there is a wealth of skill, experience, and knowledge, on this board. Ken has agreed to help me at Summit this year and Bruce if he makes it to VIR this November. Having said all that I still am Impressed with the way the snake works. I had an instructor go out with me late last year to sign me off to run in the advanced group and he said he had never ridden in Mustang that well sorted. Thanks everyone for sharing what you know. Peace, Skeet.

Sounds like you have the right attitude when it comes to tracking, I wish you all the best!! Hopefully we will meet up some day and I will get the privilage of buying you a beer. :beer:

Brian

 

[Cobra-R]

Hi Thomas,
You and your dad planning on going to CMP next month?


Brian

 

[ac427cobra]

Ok Guys, grab a drink, you might need it! Just so you know, this is the condensed version!

After purchasing a spare IRS off of ebay, I stripped it and sent the cradle to Kenny Brown to reconfigure the pivot points for the control arms and install the rear hard mount. Sounds simple enough!

When I received the unit back it was not assembled. After trying to fit the lower control arms into the cradle I knew why. I had a VERY difficult time putting the control arms into the cradle. Even with a round pry bar I could not get them to engage. Finally after rebending the buckets in a direction that worked in my favor along with the help of a pry bar I was able to thread the bolt with an impact through the hole. This photos show what I originally had:

This was the front of the left rear control arm:

This was the front of the right rear control arm:

You can clearly see the torque these poly bushings are under and the shoulder of the poly is nowhere NEAR where it needs to be. It took great force to actuate the control arms. So I called Rich and told him the condition I had and shipped the unit back to him. After about two weeks he informs me the unit was damaged in transit!! :bs: :bs: :bs: I even had Kenny on the phone at one point and he told me they take a rod and run it straight through to line up both buckets before they weld them in place. (later I discovered it is physically impossible for a rod to go through both buckets for the LCA's at the same time because the cradle member is in the way for that to be possible. So, in other words, Kenny was lying to me! :fm: ) So, I had to file a claim. We waited about three weeks for word from the freight company and I told Rich I had to have the IRS back NOW. We agreed I would pay "their cost" to repair it and when the settlement came we would square up. So I shelled out another $500.00 and they sent the unit back to me. Meanwhile the freight company denied the claim because more than 30 days had passed between the shipment and the claim. (I had the unit for about two weeks initially) So I ended up eating it!

When I get the cradle back, the holes in the buckets are elongated so pressure is no longer torquing on the bushings! :kaboom: :burn: I was like WTF? So by this time I'm rushing my ass off to get the car done on time so I can make the Spring NASA event at Road America said I'll fix it next Winter when I put Delrin in there.

When I go to put the cradle into the car, the cradle is too small by 3/8" from going onto the chassis on the rear hard mount! :bash: Get the torch out, and the port-a-power and spread the rear hard mount and ended up spreading it too far. Got my strapping machine out and strapped the ends and that's when I hurt my hand! :whine: So I finally get this SOB to the right size (cut a pipe to the dimension I wanted and strapped it down on there, torched it and walah!!)

So now I get it up into the chassis and the holes on the right side hard mount are a HALF of a hole off from lining up! Do you have any idea how long it takes to dremel 12mm bolt holes 6 or 8mm? :cryying:

There was a problem with the center mount for the bump steer I had to fix that I'm not going to go into here because what would be the point?

To say that I was fed up with KB at that point would be an understatement.

Remember, this is the condensed version!!

So now you know, the rest of the story!

:thumbsup: :coolman: :beer:

 

[b4409]

And now you know part of the reason why, unfortunately, they're not around anymore.

It's all a shame, you know, having one less (at least somewhat) track oriented supplier.

 

[NJ2000R]

thats just shoddy fabricating....if everything was made right using a decent jig then there wouldnt be any problems with fit or alignment....

 

[b_tone]

thats just shoddy fabricating....if everything was made right using a decent jig then there wouldnt be any problems with fit or alignment....

I don't entirely agree with the above. Even when things are jigged and welded, then allowed to cool in the jig most thing usually "spring" in one direction or another when taken out of the jig. There are definatly ways to reduce this, as in welding small sections at a time then moving to another weld area and so forth, so that you are not putting all the heat into one spot. This is all fine and dandy but Bruce did seem to have a bit more trouble than most.

I think Bruce was probably on the end of the tolerance stack up and as like tires, the parts simply did not go his way. It's a shame really as the parts that Mark and I used also had some minor issues but nothing near what you went through.

If it makes you feel any better, I have had the same issues with both Griggs and MM K members and more factory stock parts than I can count.......

Moral of the story: It sucks, fix it right, use it because the kinematics are good and move on.

bpt

 

[Exit Speed]

:rolling:

I don't entirely agree with the above. Even when things are jigged and welded, then allowed to cool in the jig most thing usually "spring" in one direction or another when taken out of the jig. There are definatly ways to reduce this, as in welding small sections at a time then moving to another weld area and so forth, so that you are not putting all the heat into one spot. This is all fine and dandy but Bruce did seem to have a bit more trouble than most.

I think Bruce was probably on the end of the tolerance stack up and as like tires, the parts simply did not go his way. It's a shame really as the parts that Mark and I used also had some minor issues but nothing near what you went through.

If it makes you feel any better, I have had the same issues with both Griggs and MM K members and more factory stock parts than I can count.......
That is well said. We do modify our cars quite a bit and problems inevitably show up one way or another and it could be someone elses fault or our own. There are a load of things that can go wrong before, during, and after track events and some can be very costly.(crashes, blown engines, cooked diffs, etc.) This is what is part of the hobby we so love. Live, learn, try to enjoy whatever falls in our path. :rolling:
Moral of the story: It sucks, fix it right, use it because the kinematics are good and move on.

bpt

 

[ac427cobra]

Tonester:

I agree with you to a point. But I found the KB stuff to be WAY below the quality curve IMHO.

:thumbsup: :coolman: :beer:

 

[NJ2000R]

I don't entirely agree with the above. Even when things are jigged and welded, then allowed to cool in the jig most thing usually "spring" in one direction or another when taken out of the jig. There are definatly ways to reduce this, as in welding small sections at a time then moving to another weld area and so forth, so that you are not putting all the heat into one spot. This is all fine and dandy but Bruce did seem to have a bit more trouble than most.

I think Bruce was probably on the end of the tolerance stack up and as like tires, the parts simply did not go his way. It's a shame really as the parts that Mark and I used also had some minor issues but nothing near what you went through.

If it makes you feel any better, I have had the same issues with both Griggs and MM K members and more factory stock parts than I can count.......

Moral of the story: It sucks, fix it right, use it because the kinematics are good and move on.

bpt

I agree that pretty much any material moves when cut, machined, welded, etc, but if done by a decent fabricator, ie: one who knows how to weld, will minimize the movement, and you'll end up with a good part....minor movement we can live with....but something as far off as bruce's mount is just plain inexcusable.... :bs: :bs: :bs:

and to say "you should be OK" when something is that much off, is beyond belief.... :rollseyes

I'm not trashing kb's design, like you said, the mechanics are great, its a quality issue....

if nobody owns the rights to the design (no idea if it is protected via patent, etc) and there is a set available, I wouldnt mind having my fabricating shop look at them and quote manufacture....

 

[Billy Madrid]

My Experience With KB Control Arms

Just thought you guys should hear my experience with Kenny Brown Control Arms. I am one of Tim Brown's co-drivers in his race prepared 2000 R.

Back in 2003 we were running full Kenny Brown Control Arms (front and rear) as well as the Kenny Brown front sub frame on Tim Brown's Cobra R. I had the fun experience of having a driver side rear upper control arm break (at about 150 mph) going into the braking zone in Turn 1 at Portland International Raceway. We were running in the 8-Hour Enduro and it snapped at about 7 1/2 hours right at the tube bend. It was obviously flexing a ton and gave at its weakest point. I was very very fortunate to keep the car off the walls as it tank slapped very hard in both directions as I tried to slow it down. I still think about it, though usually at 3:00 am when I can't sleep. :-D

We checked the car after that race and found the passenger side upper arm was starting to crack as well. We had a very good race fabrication shop in Vancouver fab up 2 new arms and they also fully gusseted the lower rear arms as well. The lowers lasted another year as they hairline cracked in 2004 and snapped during a passenger Ride and Drive program. The only thing that held them together was the extra gusseting we added. We had the same shop fab up some new lowers as well.

Just found out that both of the fronts are now cracked after last years 8 Hour Race and the only thing holding them together was crossed fingers and the extra gusseting we added.

Anybody who is running the Kenny Brown stuff should go out and check the control arms thoroughly for hairline cracks before going out on the track again. You should also seriously look at adding some extended gusseting to the existing Upper and Lower Rear Arms as they definitely have some manufacturing issues. Not trying to beat up the KB Product line, but in seeing the fitment issues some people are having, combined with the durability issues we had, I would hate to see a very rare car written off due to this issue.

 

[93SVTCobra]

Bill,
Very cool of you to join us!

Would you happen to have any pictures of the areas that you experienced the cracks in as there have been some design changes which MIGHT have fixed the issue on the rear upper arm. Do you know if the frame rails are notched to accomodate the arms movement or was the arm bottoming out on the frame rail?

 

[Billy Madrid]

I don't have any shots of the arms as they failed over 3 years ago and were replaced with new ones. I distinctly remember that the crack started at the end of the existing KB gusset and wrapped itself around the tube from the top through to the bottom on both sides. The one that broke, you could see some working cracks in the plating that existed before the main crack fatigued through.

The rear back upper arm tube broke first. There were no witness marks on the arm to show any physical contact with the frame. I honestly can't say if the frame was notched or not.

One thing I have noticed is that the arms we received were plated and the ones in the pictures above look like hammer tone paint. Our plated arms after cracking, leaked out some of the plating liquids that had been trapped in the arm by welding. I am no engineer, but I have worked in the auto industry in product developent and I was concerned about the 2 things with the arms:

1) the gusset ending right at the bending point of the tube, setting up a major fatigue point right where it shouldn't be

2) plating the arms. Plating causes some embrittlement of the metal surface offering a less than optimum situation that could foster cracking and a fatigue break

I think that if it had happened only in one arm then I could accept a 1 off, however all 6 arms have basically suffered the same failure mode in different areas at different times. Could it be the plating, not big enough tubes or basic gusset design. I am not sure as I know many people who have successfully used KB products for years with no issues. Maybe we were unlucky.

Again I am not trying to cause any issues as we might have been exceeding the design loads the arms were made to operate under. We were using Dunlop slicks and running the car very hard and the first arm that broke was the outside rear upper arm. We had however been advised that they would work in this application. I am certain that some of you might be approaching the design limits of the arms as well and just wanted to have you guys pay close attention to them.

I am very privileged to be able to have spent a number of hours of seat time in one of these cars, albeit heavily modified, and just don't want to see one damaged when it doesn't need to occur. :burnout:

Oh, by the way my real name is Eric Nummelin. Billy Madrid is justmy cooool name. :rollseyes

 

[ShelbyGuy]

are the kb upper arms made with a different curve or inner mounting point than the factory arms?

aside from lightness, is there any other benefit?

 

[93SVTCobra]

Oh, by the way my real name is Eric Nummelin. Billy Madrid is justmy cooool name. :rollseyes

Well I'm going to keep calling you Billy then! :banana: