Sway Bar \"loop hole\"???

#1

Does anyone have a picture of the ST sway bars? I may be opening a can of worms here and not sure if anyone has already picked up on it but as it is a spec series and for the good of the series let me open the door.

The rules state a 22mm non adjustable front sway bar SHALL be used. It also states that the sway bar can be of any manufacture. Since I want to build my last race car I am choosing to use the best of parts and build it right just once. So I figured based on what everyone was saying about the IE sway bars being easier to install and such I figured I would get a set. So I did.

Now from my ITS E30 I have a 22mm (I think) ST front sway bar that I removed and replaced with a 25mm hollow bar. I decided to do the math and see which sway bar was stiffer. Guess what? The ST bar is much stiffer. To the tune of K=850 lbs/in for ST and K=520 lbs/in for IE. What really got me thinking about this was seeing a picture of Patton’s taxi in GRM. I was reading an old issue and saw his car in an add or something. The Taxi was leading a 944 but had a lot of lean (in Oak Tree I think). I was thinking "I sure hope the cars don’t roll that much". I then got to thinking that "I" could manufacture a "non adjustable 22mm" sway bar and just make sure the pick up point is far enough back to get the optimum K value.

So, I guess my real question is can anyone confirm my findings? I have not taken the measurements from my ITS car’s rear bar which also the ST bar. I wonder if I will find the same thing?

Patton, what bars are on the Taxi?

Comments?

Michael O.

PS: I may have my calculations all wrong as well.

#2

Sounds legal to me, and depending on how well it works you can manufacture me one as well.

And yes the cars do lean that much but it really doesn’t feel like it when you are driving it.

#3

Now before I ask my question and look stupid understand that I’ve always been challanged in reading comprehension and my head is still spinning after reading your post, twice.

So here’s the question. If the 22mm ST bar is stiffer than the 22mm IE bar and you have the ST bar, why not just use it on your SE30 car? I’m obviously missing something so help me understand.

#4

Mike, the Taxi has the Ireland set-up. Yes, it sways, but so does everyone else. Rob at Bimmer world was/is tinkering with a different/stiffer front sway bar set-up using some of the calculations that you’ve referenced. I don’t know where they are in development. Will their stiffer front sway be the next big thing? Only if someone is faster with the latest hot rod part. In the interum you may want to try some spacers to push the wheels outward. Regards, Robert Patton

#5

what you suggest sounds legit with the current rules - the racing dynamics bar actually has 3 holes in front and you get to pick one and stick with it. However, I wouldn’t be surprised if a rules change was made if an overdog creating development surfaced - the whole point of the series is close racing, not for clever loophole exploitation. This would be a case where a rules change would create "rules intent" stability. Just my $0.02

cheers,
bruce

#6

I understand that I could just use the ST bar and have the stiffer bar. I assume the rules are so everyone is the same. The reality is that even thought a 22mm non adjustable bar is speced. All the bars are not the same spec. So why limit them to non adjustable? The reality is that it is adjustable by changing bars. You could also cut off the existing mounting hole and weld on a new one a little closer to the pivit. The possibilities are endless.

Michael O.

#7

My question is why would you want to?

I chose this series because I DON’T want to fiddle with every little thing. Set it and forget it. Either I’m fast or I’m not. The cars should be the same.

My .02

JP

#8

The way I understand the rules is that you can you the sway bar links that come with the manufacturer of the sway bar. So if they are adjustable then you can have an adjustable sway bar.

9.3.8.8.1. Anti-roll bar links provided with the bars from the manufacturer are permitted.

#9

I don’t want to fiddle either. The point is the cars are not the same. Which sway bar do you have?

Shocks, Springs, Camber Adjustment, motor, etc. all the same. All the performacne stuff the same or at least the same function. Sway bar not the same and offer different performance potential.

I guess some bushings are different and may offer different performance.

Just keep in mind that the choice of sway bars may make a difference in how the car handles.

Michael O.

#10

Adjustable links allow you to adjust the preload not the stiffness. On a road course most typically set the preload to zero meaning the bar has no load in the neutral position. An adjustable sway bar has different mount holes for the links. As the link is moved to a hole closer to the bar it becomes stiffer. As it is moved to a hole away from the bar it is softer.

Michael O.

#11

I don’t know about the other bars, but my ST bars did not come with front links, so the default is the stock link, which I replaced with new ones. I have noticed other cars have adjustable links up front, but they didn’t come with the ST kit.
Ed

#12

Ken,
an adjustable sway bar (to me) means that the attachment point of the end link can be moved closer or further to the pivot axis of the bar (the lever arm length), not that the end links are adjustable.
cheers,
bruce

screwynewy wrote:

[quote]The way I understand the rules is that you can you the sway bar links that come with the manufacturer of the sway bar. So if they are adjustable then you can have an adjustable sway bar.

9.3.8.8.1. Anti-roll bar links provided with the bars from the manufacturer are permitted.[/quote]

#13

Am I missing something here? You did some math and concluded that the 25mm hollow bar from IE is not as stiff as the 22mm solid bar from ST? Did you also do the same comparison with the 22mm IE solid bar? Seems like that would be the more interesting comparison since both are SE30 legal. Also, how did you setup the math? Did you just assume the same type of material for both bars and just compute the torsional resistance of a 25mm hollow bar vs. a 22mm solid bar?

I’m in agreement that there are many ways to get adjustment in the front bar so we might as well make it cheaper to adjust them by allowing adjustable bars.

And what exactly constitutes adjustability? You can take a power drill and drill some new holes in the front bar and slap some quick-dry epoxy over the old holes and you’ve just adjusted your bar in between sessions. Is that considered adjustability?

#14

Sorry to be confusing. The calculation that I did was with the 22mm IE and 22mm ST bars. I will verify the ST bar today and make sure it is 22mm. Both Spec E30 legal. I used the equation in Fred Phun’s book "How to make your car Handle". I guess the equation assumes the same material for each bar.

I agree that you can adjust a non adjustable bar by doing what you indicated. If the IE bar fits better that is what I plan on doing. Cut off the tab and re-weld it in another location. I don’t want to get cought with inferior bars.

I think that the front sway bar is a critical suspention piece as with the shock and spring package I think the cars are under damped.

Michael O.

#15

<<<<< Getting the popcorn ready for this one!****

#16

I am not trying to cause any troble what so ever. The rules say what they say. If I manufacture my own bar and make it non adjustable the rules say it is legal. I would prefer that the stiffness of all the bars was the same and everyone is on the same equipment but that is not the case. Maybe a rules change will make it the case and if so I hope the change is made sooner than later.

I brought this up because I figued that no one had really done the math yet. As the series grows so do the number of people reading the rules for what they say, not what they should say.

Don’t fool yoursleves and think that with Simon, Jack, and others coming to play that they are not doing the same &quot;thinking&quot; that I am. Simon can drive the hell out of a car and you can be assued that it will be a very well prepared car. I also hope to have a very well prepared car.

The engine rules are iffy as well but I prefer to do the 100K miles junkyard engine route. Just don’t be suprised if someone else actually builds a motor for this series.

Michael O.

PS: Simon, please don’t take this as a dig, It is with the up most respect I say what I say. I have seen your old car and you drive.

#17

What do you mean by the engine rules are iffy?

#18

That is a topic for another trend.

Michael O.

#19

There will always be someone who will try to get an edge. We’re racers, after all. I think what’s important is the INTENT of the rules. If it doesn’t say you can do it, you can’t. By the same token, if you don’t want to play by the rules, all of them, you should play somewhere else. Modifying a bar in that manner to gain an advantage, I think, says volumes about someones character.Just my .02

#20

There will always be someone who will try to get an edge. We’re racers, after all. I think what’s important is the INTENT of the rules. If it doesn’t say you can do it, you can’t. By the same token, if you don’t want to play by the rules, all of them, you should play somewhere else. Modifying a bar in that manner to gain an advantage, I think, says volumes about someones character. Just my .02