Jump to content

A-arm ruling


Recommended Posts

Posted

Now that I'm an expert on these cars ( well- we have the interior stripped at least ! ) one more clarification with regards to the front lower A-arms :

- because of the safety issues with the stock units that I have been reading about, can they be updated to a fabricated steel aftermarket type?

- if not, what would the suggested max. ride height be or should I not be agonizing about this issue.

Thanks again guys ! Cheers, Max.

Posted

I have used stock steel arms on my car for a long time. They are really the best solution as they are cheap and don't suffer from ball joint problems. They can crack however, but the nature of steel means a small crack is not problem. Because the material is steel it takes a very long time for the crack to be a citical issue thus inspections (like when changing tires) can catch the problem and then since new arms run $25 or so each you can keep spares and change them in 30 minutes.

 

Plust in minor wreck the steel arm will bend taking much of the loads this keeping the rest of the frame work straight. So in effect you sacrafice the arm to save the rest of the parts.

Posted

Thanks Joe - but do these stock steel arms fit the later cars too ? I am talki.ng to a fabricator of an aftermarket arm and he claims to have a certificate from PCA that allows use of his arms in any existing 944 racing class regardless of what the original rulebook stated, because of the safety issue. What is NASA's take on this ? Max

Posted

hmnn, thats interesting, can't wait to hear final word on that... Yes, the steel arms can be used on later cars (basically a direct swap on an 85.5 & 86) but with the 87 on you would have to replace the whole front suspension due to the different offset (including early wheels.) Doesn't seem worth it unless one had the parts laying around.

Posted

Tough to beat the steel front control arms for strength or price.

2 more benefits of using the Steel arms are that the ball joints can be replaced track side, and that the ball joints can be installed facing up or down for a driver's side piece or a passenger side piece.

I've been communicating with Karl from Racer's Edge about his control arms. It's not up to me whether NASA or PCA accepts his parts, but there seems to be a big improvement in safety over the stock ALUMINUM front control arms. I don't have a problem with them because Karl states they are the same size, geometry. No advantage, just safer.

Posted

If aftermaket arms are allowed, would that include 'Charley arms' or other brands?

Posted

Not sure. They would have to be identical in geometry, ball joint pin length, etc, to even be considered. If only one reason to use them is for a performance advantage, I'm positive it'll be shot down.

Posted

I raced a 944 with steel arms from the late 80's until 2000 and only experienced one damaged arm (from an off track). As was already stated on this forum, the steel a-arms are very low cost. I much prefer the steel arms over the Charlie Arms.

 

Later I built a 3 liter car with the Charlie Arms. After watching several of my friends wreck cars with Charles arms, I noticed what I believe to be a trend. It seems to me that it is better to bend an a-arm than to bend the tub.

 

The Charlie arms are so strong that my friends who crashed with charlie arms on their car ended up with perfectly good Charlie arms, but the energy was transferred to the tub resulting in a totaled car. I would much rather change an a-arm than change a tub.

 

The bigger suspension issue to me is the spindle on some of the early 944 and 924 where the speedo cable is passed through the middle of the spindle on the driver side. I have had the spindle break off completely while on track. As you can imagine, when the spindle breaks the wheel, brake rotor & caliper seperates from the car. This results in the car becoming a tricycle with the front brake curcuit becoming ineffective.

 

If you have an early car where the speedo cable is passing through the spindle, PLEASE inspect the left spindle on a regular basis.

Posted

The 87-88 924S's also have this same system of the speedo cable passing through the spindle (steering knuckle).

Posted
The bigger suspension issue to me is the spindle on some of the early 944 and 924 where the speedo cable is passed through the middle of the spindle on the driver side.

 

I think this is place where the small not so sticky toyo's, softish spring rates combined with the light weight of the car is a big help.

 

Yes those spindles are a bit weak, but I don't believe our cars put that much stress on them. This does not mean you don't need to inspect them, but I do think it explains our ability to run them.

Posted
I think this is place where the small not so sticky toyo's, softish spring rates combined with the light weight of the car is a big help.

 

Yes those spindles are a bit weak, but I don't believe our cars put that much stress on them. This does not mean you don't need to inspect them, but I do think it explains our ability to run them.

 

 

Guys,

 

You are both correct in that I was running sticky tires (hoosiers on 8x16 and 9x16) on fuchs wheels and a very stiff suspension (coil over set up on all four corners) and higher weight (2779 pounds) of that '83 944. As you can tell, my previous experiences are some of the reasons I am so excited by the suspension, tire, wheel and weight rules in this class.

Posted

Thanks to all for the comments & input - but unless I missed something - no one really answered my original question - can we use an aftermarket steel A-arm on the later model cars due to safety concerns & assuming they will not give any performance advantage. Yes / No ?

Posted

Which aftermarket arms?

 

There is no blanket allowance on arms. You would need to gain approval from a series director for the specific arms you chose to use.

Posted

Joe,

 

This is a slippery slope. The aftermarket arms DO give performance advantage, and although I manufacture them (and would love the 944spec business) they are just too expensive to justify in a spec car...

 

If anyone wants them for their street car, turbo, etc... They are Cromoly and sell for $1595 a pair.... just in time for Xmas.

 

Check Lindsey Racing, who markets them for us...

 

http://www.lindseyracing.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=LR&Category_Code=LINDSEY

Posted

Jim this is the exact reason they are not free per the rules.

Posted

btw jim... Those arms put the rod end into a very bad loading. The base of the rod end (threaded part) is put in bending during heavy braking. Rod ends are not designed to take bending at the threads like this and are much weaker than their load rating in this form. I can't say they will fail as they may simple be thick enough, but that is not a loading I would trust. You are putting the place of peak stress in the weakest part of the arm.

 

 

 

lindseycontrolarmLL.jpg

Posted

Another thing to think about is bushings must remain not-metallic. Most of these arms use spherical bushings for the crossmember and caster block mount. They would be illeagal on this issue alone.

Posted

They should be illegal just because they are non-stock. We have rules to allow a few mods and the rest are illegal. Keep the rules as they are. I know I am out of the picture but I may rejoin. (Doubt it!) The reason is the rules need to remain stable!!! A few years ago modified A-Arms would have been shot done instantly. Next thing you know port and polished heads will be O.K. so log as stock specs are met??? Find/prove any/if cheaters. I personally do NOT think anyone is cheating!!! The rules need to be 100% defined for 0% leway!!

A-Arms shouldn't even be up for concideration!!!!!! These are NOT Spec.

Posted

Hey Eric - I hear what you are saying and totally agree. I was only looking for someone more in the know than me to address the possible safety issue and if the consensus is that it's not a problem and we have to use stock arms then I can move forward with the suspension work on my car. I'm ok with whatever the final word is and I'm hoping it's stock arms and they are going to be safe given all other parameters of the class specs.

Posted

Mad Max,

count the number of cars, across the number of groups, over how many races have been run, and then figure how many failures there have been which I think is zero on the arm itself? Seems like you should be cool with stock arms, everyone else is.

 

P.D.

Posted

I think dylan is right on one point. No failiures of the arms. There have been 2-3 ball joint failures on the alumininm arm cars.

 

Jim Marks at Cal speedway in 2005

I believe Glenn Gormely had one.

And

I think Mark Foley this past weekend at Willow with POC.

 

I agree that stock should be stock, but at the same time I don't want to force people into parts that could fail. PCA recognizes there is an issue. We have lots of races under our belts with few problems, but It is somethign we need to be aware of.

 

In PRINCIPLE an arm that does not provide an advantage yet is reliable is the answer. Problem is nearly all if not all of these arms are also a performance advantage in some way. Now there are ways you can mod stock steel arm to make it stronger at weak point, but not impact its overall stiffness. Even then these still can't be used on 87 and 88 cars.

 

 

In the end I am not 100% sure what right solution is. I can say there two schools of thouht on this PCA says replace them since they are weak. SCCA ITS says no. Must be stock if they are weak that is your problem.

Posted

I, too, have seen no control arm failures, but add me to the list of drivers who have had ball joint failures in the 85.5-86 aluminum control arms. All my cars now get back dated with the stronger steel control arms.

I'm not quite as rabid as Eric about keeping the rules as is, if there are ways to make our cars safer, better, easier to maintain, etc., but in this case, stock has been good enough.

Posted (edited)
I think dylan is right on one point. No failiures of the arms. There have been 2-3 ball joint failures on the alumininm arm cars.

 

Jim Marks at Cal speedway in 2005

I believe Glenn Gormely had one.

And

I think Mark Foley this past weekend at Willow with POC.

 

No failure for Mark Foley, interesting how 'completely inaccurate' information can get around? But anyways.

 

I think Jim's failure was on the longer ball joint, I too had them until they were ultimately banned as illegal.

 

Have the failures on the aluminum arms been on rebuilt ball joints, or on 20 year old junk?

Edited by Guest
Posted
I, too, have seen no control arm failures, but add me to the list of drivers who have had ball joint failures in the 85.5-86 aluminum control arms. All my cars now get back dated with the stronger steel control arms.

I'm not quite as rabid as Eric about keeping the rules as is, if there are ways to make our cars safer, better, easier to maintain, etc., but in this case, stock has been good enough.

 

Are the 87+ conrol arms any better? As I just bought Chuck Taylor's (SVO Chuck) '88 spec 944, this is now of interest to me. If I did back date o the steel arms, would I have to run early offset wheels in the front only?

Posted

I beleive that the 87, 88 control arms are better... I know that some, here, beleive that the safety issue makes the steel Control arms better than the 87-88 arms, (even though the 87-88 have better steering geometry and less bum steer)

 

However Sterling Doc, if you wish to go to steel arms, I will gladly, buy a pair, have them professionally box welded and ship them to you free of charge, in exchange for your "inferior" late aluminum (failure prone) 87 control arms....

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...