Geo

Isn't it the competitor's responsibility to inspect their car and make sure all the components are up to snuff? Wheels fall of race cars that have worn or cracked wheel studs. Is this different? I don't think so.

RedlineMan

Hey G;

Do you walk to work, or carry your lunch?

I don't get your point?!

There are random failures, known failures, and ignorant failures.

Random failures are ANY PART of a car, truthfully. Things fail, that's a fact, and it's not possible for inspection to 100% solve that. You can only do your best. That's just the way it is.

Known failures are weaknesses in design that have proven to be a problem over and over again.

I classify the steel arms as the former class, and the alloy arms as the middle. I don't think there is any disputing that. Ignorant failures are there own reward!

In the strictest literal terms, Sam stated emphatically that alloy ball joints never pop out unless the car is over-lowered, and further that steel and alloy arms are the same in normal OE use. I did not think he meant in EVERY instance, and took the liberty of qualifying his statement.

If what he meant it as I qualified it, then he makes more sense, but I still dissagree because I see them fail on stock street cars all the time. In case he DID indeed mean that 100% emphatically, then I totally utterly dissagree with him. That is simply not true.

The alloy arms suck, and Im not changing my mind!

Bill L Seifert

Geo, and everybody,

Just one last thing I want to say. If the FABCAR and Charlie Arms are safer, and Bruce Anderson, Jim Pasha, etc say they are, then why the heck would the SCCA care if they are changed. All that has to happen is the Comp Board passes a rule that they can be changed. If anyone can say that is a performance advantage, then I would understand where they are comming from. But they are heavier, (more unsprung weight) But the bottom line is the alloy arms break, say what you want, but they do. By the way, IMSA, GrandAm, etc let the 944/968's run the bars when they were running those groups, it just sounds like stubbornness to me.

Anyway, I will do what I want, and if someone wants to protest, then so be it. But it will have to be a protest, cause no-one except tech will look at my a arms. So if some of y'all walk by my car in the pits, and I have a tarp over the front of my car, start protesting. But remember, protests cost money.

This is about the wierdest discussion I have ever been in.

Bill Seifert

Jerry Ljung

In the interest of creating a data point, can anyone define the term "over lowered" ? (for stock, inspected, rebuilt a-arms) I will say this, a measurement of 5" at the forward end and 5 1/4 " at the rear end, of the rocker panel to the gound, is not "over lowered" for a 944, in my opinion. Please educate me if I am in error.

Sway bars are essentially stock, and spring rates are 600/550 f/r (torsion bars machined to essentialy zip), eliminating the issue, in my opinion, of the overly stiff sway bar fighting stock springs stress problem.

Best Regards,

J

RedlineMan

Hey Bill -

Although it has strayed a tad, it is nonetheless what I had hoped for when I started it - a thread that brings everything out for discussion. I would say "wierd" is a bit strong a term. I do understand and agree with your position on the arms, though. It is a safety issue in my mind, pure and simple.

I also see Geo's point and "understand" the SCCA's reluctance to "open the barn door" to changes such as this, although I don't personally agree with it either. I know how people are, and so do you, methinks. Racers will pull all kinds of stunts to try and skirt the rules. Seems they will gladly expend large amounts of energy to beat a rule, when that energy could have been much more wisely expended elsewhere.

By sticking with the OE rule, it reduces the amount of legwork necessary. Again, while not agreeing with it in principal, I clearly see their point here.

Jerry -

Zone 1 PCA adopted a lowering measurement rule for 924-968 front ends. I'll be damned if I can find it anywhere. If someone doesn't beat me to it, I'll get that measurement for you. I don't know from whence it was derived, but somebody had to have done some thinking on it!

Geo

And 5" is the legal limit for SCCA ITS which Bill and I run.

Another thing I've been meaning to ask......

I'm having a bit of a hard time blaming over lowering. If lowering the car ruins the balljoints due to binding, what happens due to natural suspension travel, lowered or not? The control arm will swing even higher up than simple lowering would. Something sounds wrong.

A number of things come to mind.

If the balljoints bind within the limits of suspension travel, that's a serious design flaw. Has anybody ever removed the springs and tested the limits of the suspension while on stands to find out exactly how far the suspension can travel w/o binding the balljoints?

If balljoints are binding on lowered cars, it's not the lowering per se that is causing the problem. It's the fact that the suspension is traveling farther than it should. In this event, stiffer springs are the order of the day. Speed Touring cars use crazy spring rates to limit suspension travel because of camber curves. Perhaps track/racing 944s need to use higher spring rates to limit suspension travel due to the balljoint issue. I was planning on 500lb springs up front. Perhaps larger are in order?

I wonder what spring rates people are running who experience failures?

Not that it is legal in SCCA IT, but if the billet A arms use spherical bearings, why doens't someone convert the factory aluminum arms to accept spherical bearings? It can't be any harder than modifying them to accept replacement balljoints.

RedlineMan

G -

You raise some good points. Bravo! Your assertions seem perfectly logical to me. All I know is that at the height I keep my car I have had no problems. 25" to 12 o'clock on the lip front, 25.5" rear. I used to have it lower, but it was a bloody pain with jacks, trailers, and such!

I do not know how Zone 1 came to their height measurement. I can only assume someone burned some brain cells on it. When I get that height measurement, I'll post it.

Al P.

Hi Jerry,

In the words of my regions tech people " Lowered 944s are subject to catastrophic a-arm failure"

To cut through some of the defensive retoric, the accusations of whatever etc. and to put some focus on the actual technical matters at hand here.

First there are at least three or four technical issues none of which are related to whether or not a particular a-arm or modification is or should be legal under one sanctioning bodies GCRs and not anothers.

1. the early steel a-arms, (a volkswagen rabbit part) can fail when used with heavy sway bars and lighter springs.. They are not very robust parts but can easily be reinforced to "race spec." The replaceable ball joints used on these arms however seem to hold up very well and don't seem prone to failure.

2. if you lower a 944 with the later aluminum a-arms you stand the chance of having the ball joint bind and fail. (I've seen three fail at DE's) As far as I know there is no magic number that you can lower the car to and be "safe"

3. the aluminum arms were not intended by the factory to be rebuilt or serviced. They were to be replaced when the ball joint wore. The cost of replacing a perfectly good arm with an even slightly worn ball joint has led to the developement of "re-build kits" some better than others. None of this has any bearing on point two except that if the aftermarket rebuild kit is not as strong as the factory ball joint it would have even more of a tendency to fail from lowering the car.

4. there are several non-factory replacement options available for owners of aluminum a-arm cars that will reduce the risk of this type of catastrophic failure.

Personally I don't see the argument for requiring OEM a-arms if the aftermarket replacement doesn't change the suspension geometry in any way. Nor do I accept the arguement that I've chosen a car with a known defect to race so it's my problem, when that known defect is correctible with a part that doesn't provide a performance advantage. Now when Porsche runs out of OEM a-arms will those that chose to race with a sanctioning body that insists on an OEM a-arm be required to rebuild a part that the factory said was non-rebuildable, using a kit that may or may not be inferior to the factory part? (before all the makers of rebuild kits send me hate mail I'm making a point here not condeming your products). I can't imagine that every car listed on a "line" in the SCCA's GCRs has all the OEM parts available and at some point reproductions or aftermarket parts must have to be accepted

Race safe, remember the sheet metal you save may be mine

Bill L Seifert

Geo

I have spherical bearings in my modified steel arms on my 1983 944 Race Car, and I think I could use spherical bearings on the alloy arms. Butttt, from everything I have heard the ball joint can still pull out because of the angle of the joint from being lowered. If you look at a 944 that has been lowered (Mine has been lowered 1 1/2 inches) the a arm angles upward toward the strut from the crossmember about 30 degrees. Therefore the ball joint doesn't have as much room to move on the outside as it does on the inside. I guess this makes it bind when it hits the stop. Then breaks if you exceed that. I will admit that I don't have as heavy of springs that I could have, 260 lbs, as opposed to the available 400 or so.

Anyway, I am afraid of the alloy arms because of all of the failures I have heard about, and would like to use something else, and am petitioning SCCA to do just that. Though I don't hold much hope.

You know, I have only seen one a arm failure myself. That was John Crosby, who is one of the best 944 runners in the PCA. He is one sharp guy, and by the way, is now running PCA Club Racing. What happened on his was, in my opinion, the fault of whoever built his car. (His old car, not his new turbo) If you will remember the steel arms have two bolt holes to mount the sway bar. Whoever built the car drilled another hole between the stock holes to mount the Weltmeister sway bar. In effect what they did was perforate the a arm (Tear along dotted line) At IRP the a arm broke in two, and John went for a wild ride, and tore up the left front wheel well. (He got it fixed and won the race the next day, by the way.) I think that if they had welded the two stock holes up, the arm would never have failed. That said, I really think that there needs to be an optional a arm for the Alloys.

Bill Seifert

Geo

I seriously doubt it's the lowering that is the issue. See my post above. I submit it's lowering with springs that are too soft that allow the suspension to travel beyond its usable range that causes them to fail. The limit of the usable range is defined by the limit of the balljoint. Even a stock car at stock ride height could bind a balljoint in this case.

See above.

OK, a couple of things here. First of all, non-OEM parts, unless specifically approved in the ITCS are not legal (technically speaking). We are currently working to correct this. However, the alternate parts will have to be OEM requivelent replacement parts. This will have to be passed by the Club Racing Board and then the Board of Directors.

Second, when the parts are gone they are gone. Unless there is a massive change in philosophy in IT, don't expect change here. We just went through this with a 30 year old car. When parts are gone they are gone. Period.

Geo

Bill, I would get stiffer springs ASAP. Springs are available above 400. The usual "limiting" factor is the rear torsion bars. Jason at Paragon can get you custom torsion bars. IIRC they are the same price as the hollow Weltmeisters.

I'm going to order a custom set.

I think the spring rates is what should scare you, not the arms. If you limit the suspension travel, the balljoint cannot bind.

Premier Motorsp

It is funny that no one has mentioned the REAL reason the ball joints fail on alloy arms. It is really important to know this because is sets the stage for something you are going to have to deal with throughout your whole 944 racing career:

On cars built prior to -87, NONE of the front end parts are strong enough for the loads involved in racing. Every part in the front suspension can and eventually will fail catastrophically.

It is all metal fatigue. Yes, in unusual cases the ball joints can get bent over by over travelling. I doubt they would snap off instantaneously, but being bent over does nothing good for the fatigue life.

The harder you work thse parts, the shorter the fatigue life. On 225/50 15 tires and stock brakes, your parts are probably going to last a while, maybe a few seasons. On 285 slicks on 10.5 inch wheels, you will be lucky to complete a race weekend.

The reason Fabcar and Charlie arms are effective it is that the strength of the ball joint pin is so high that the loads involved are below the fatigue limit of the part. Of course if your car gets really fast, you might just start incurring loads that are above the fatigue limit, which means these parts WILL eventually fail.

The design of the factory ball joint pin is pretty inexcusable. The 360 degree groove pretty much guarantees a failure at the bottom of the groove. The ball joint's play-free life span is incredibly short on a race car as well. Despite this, I am not really in favor of steel arms, modified or not, on GT-type 944s. They are not stiff, and will eventually fail near the inner bushing hole. I am sure they are fine on cars with smaller tires.

Once you overcome the ball joint issue you move on to hubs, spindles, and steering knuckle pinch bolt failures. The real solution is to change to Turbo S hubs and spindles which are probably twice as strong and almost strong enough for a decent GT car. This is inconvenient and expensive of course, and even these parts break when they get enough miles on them.

In short, the pre 87 parts are unacceptable for anything but a very limited car like a 944 spec, and the post 87 parts are decent for anything but a full blown GT. In any case, regular inspections are a must.

Chris Cervelli
Premier Motorsports

Bill L Seifert

To Geo

I have 30mm gundrilled torsion bars on the rear of my car. Also, remember I am talking about this subject because of the new car I am building, a 1987 944S. I will use at least 450 lb springs there. I have been racing the other car for 15 years, and because of the care I have taken with the steel arms, there have been no problems so far.

I just talked to Markus about his steel a arms. He forwarded a letter from Porsche that approves his arms for PCA racing. (of course I allready figured that.) I am going to send that to the SCCA. He also said that there is a Porsche Tech Bulletin that says that stock alloy arms are not to be used for racing. The Bulletin says that if they are used for racing they are subject to failure. Hopefully SCCA will take that into account when they make their decision on my request of last month.

Bill Seifert

RedlineMan

Chris -

Thanks for your knowledgeable expert opinion. You obviously know where of you speak.

Scientific matters of metal fatigue are of course a reality. I can only state what I feel to be the real world case. If you were to coalesce all the data from arm failures, you would see the basis for my opinions.

If you looked at street-only, I think you would find that the failure rate for steel arms was imperceptible compared to the rate for alloys. For track you would see a slight rise in steel arm failures (usually for the reasons that Al P. stated i.e. poor preparation), but not nearly as significant as alloy failures. These steel arm failures would also likely give much more visible warning to those paying proper attention than the instantaneous failure of a forged alloy part.

If you look at the modes of failure as I have discussed, steel arms fail for basically one reason; they bend, or break in half if mods are not properly rendered. If they are run for years and not inspected, they can very occasionally fail at the front inner bushing surround. Essentially ONE failure mode of low "statistical significance."

Alloys fail in MANY ways, from ball joints pulling out to simply snapping in half. Many failure modes of statistically important quantity.

I know where my bet is being placed. YRMV! Good thread, Chaps!

Rick

I've been following this thread with a great deal of interest because I'm planning on replacing my A-arms before the season starts and will probably be going with Charley Arms.

It's my understanding that the original spindle needs to be bored out to fit the larger post since the Charley Arm pin is 19mm vs the standard which is 17mm...is this correct?

In looking around, I've found that Powerhaus supplies ball joint pins with the Charley Arms that are 17mm which will not require any machining.

Any suggestions which is the better way to go?

(Note: the price of the Arms is the same wherever I check so the only price difference is whether or not I have to have the spindles machined out).

Thanks much.

Rick