2005 rules - frame notching

[Guest]

Luna- you have officially won the contest. I owe wilson $5.

[RichardC]

How do we get more people involved in the rule decisions?

 

This thread has 51 posts (not counting this one) made by 13 people and half of those posts were made by just three people.

 

It's just as difficult (if not more) for John and his team to make decisions based on opinions of so few people as it is none.

 

It looks like 95% of AI competitors don't care what is proposed. Is that really the case?

 

Richard.

[onralz]

Luna- you have officially won the contest. I owe wilson $5.

 

uh, OK. I don't actually care why I won the contest or what the contest was, but I do want my cut. Shall I ask that you send that along with the fuel pump I loaned you guys in April? (knowing these two, they'll end up sending me $2.50 in canadian money instead of US dollars.)

[chicane23]

The frame notching should not be allowed as others have mentioned. If I'm correct the frame notching allows for a greater deal of neg. camber in the rear of the IRS car. This is not accomplished with a solid axle car without a considerable amount of cash. This making a solid axle obsolete in AI and drive AI cost up!

[NickS]

Allowing frame notching, IMHO, is just the first step down a slippery slope.

 

IMHO

 

-N

[mwilson7]

The frame notching should not be allowed as others have mentioned. If I'm correct the frame notching allows for a greater deal of neg. camber in the rear of the IRS car. This is not accomplished with a solid axle car without a considerable amount of cash. This making a solid axle obsolete in AI and drive AI cost up!

 

Frame notching doesn't allow for additional negative camber. It allows the arm to complete the same range of motion that the stock arm takes. You also don't want a great deal of negative camber in the rear of the car. It reduces your contact patch and would make it much more difficult to put power down. We already have people running cambered solid axles so I don't see the advantage there. I also want to know once again how this drives AI costs up?

 

Here is a picture of the stock arm:

 

 

Note how the arm is contructed. It leaves the carrier heading straight down and then makes a very tight turn (around 90 degrees) and heads out to the spindle.

 

Here is the KB arm (best picture I could find):

 

 

The issue us that a tubular arm can't make the same bend as the cast iron (or equivalent) stock piece so it takes a less agressive line between the spindle and the IRS carrier. If you lay the two arms next to each other the mounting holes are in the same locations. As I have stated many times before the only advantage of this piece is weight. Unless someone in the aftermarket decides to cast their own rear arm (which is HIGHLY unlikely due to the excessive cost) then this is the only viable way to product an aftermarket upper control arm for the rear IRS in a Mustang.

[D Algozine]

This issue is very important to me. I have plans to install an IRS this winter, but obviously, I won't be doing anything until this is settled. Reading this entire thread, I have one question. Is this all worth the effort to save a few pounds by using tube frame piece instead of the stock cast piece? I can't imagine anyone dominating a race series over a few pounds. If it's just a weight savings, why not use the KB kit with the stock upper arms? Can KB design an upper arm that is solid that would be thinner, and be able to clear the frame. Perhaps another manufacturer can or already is developing one. I don't like the idea of changing the rules to meet a manufactures product. I don't like the idea of having rules read, "mounting points pretty close to the factory points" or "small notches are allowed". I don't see how the rules can be written/enforced to allow some modification to pick up/mounting points. It's either all or nothing. And I don't think it's a good idea to allow unlimited pick up/mounting points for the IRS. Things will get wild and expensive quickly.

This desicion is very difficult. The three options are all tough, but I don't think we want anything to do with number 3. (see above)

I do appreciate what Mark and Brain have done and are doing. This issue needs to be clarified along with others.

How do we go backward if these mods open the door, and provide an unfair advantage?

[mwilson7]

Anyone could develop an arm that is solid and would clear the frame rail but it's going to be expensive to make which translates into expensive to sell so no one would probably but it anyway.

 

I don't know if there is a perfect answer but if you don't allow some modification to the stock pick-up points then you may as well completely outlaw IRS's all together because keeping the stock pick-up points in the Ford IRS wouldn't make it competitive in the AI class.

 

I will throw this out there though. Both Kenny Brown and Panoz are considered automotive Manufacturers as both have Manufacturer plates issued by their respective states. You can purchase a brand new KB Cobra with a KB vin number new from one of their dealers. These cars have both the modified frame kit installed along with a modified IRS carrier. Panoz uses a Ford IRS module with modified pick-up points as well. Does that make these pieces OEM? According to the definition of OEM it does as both are considered Original Equipment Manufacturers of their respective vehicles.

 

Lastly it turns out that there are at least three AI cars that have been built with the KB system installed. One in California and two in the Midwest.

 

ANY COMMENTS ON THESE PROPOSED IRS RULES?

 

My proposed IRS rules again are as follows:

 

"How about spelling out that aftermarket upper and lower arms would be allowed as long as they would work on a factory stock IRS (this would make the mounting points pretty close to the factory points). Also require the factory rear spindles with unmodified suspension pick-up points (there may be some modifications required to fit larger brakes so I'd suggest limiting it to suspension points). And require the use of the factory IRS k-member but allow the pick-up points to be changed. Coil overs are allowed but must use the same mounting locations as the factory shocks. Sway bars are unlimited. Center section must stay in the stock location but can be modified for cooling and bushings are unlimited. That isn't perfect but doesn't that severely limit what you can do?

[RichardC]

Why is the IRS uncompetitive without changing pickup points?

 

It has reduced unsprung weight and is adjustable for alignment and has dynamic camber gain.

 

Mark, can you run the stock arms on your IRS? or do they no longer fit due to the pickup point changes?

 

Richard.

[mwilson7]

They should fit but I don't have any arms to try on it.

 

The solid axle is also able to be modified for increase in camber and toe(I believe you can add some toe). How many people running solid axles have added either of these? Not many. Until everyone has I don't see that as being a factor.

[Guest]

Why is the IRS uncompetitive without changing pickup points?

 

It has reduced unsprung weight and is adjustable for alignment and has dynamic camber gain.

 

Mark, can you run the stock arms on your IRS? or do they no longer fit due to the pickup point changes?

 

Richard.

 

The IRS as it comes from FoMoCo has quite a bit of built in dynamic understeer and compliance. This is done on all cars as a safety factor. The stock unit has rubber bushings for NVH isolation that desinigrate after a few events. The entire carrier is mounted to the body via rubber bushings.

 

For the same reasons a stock 4 link is uncompetitive with a well set up PB/TA or 3, 4 link. The actual geometry of the stock suspension is not suited for racing applications, sticky tires, increased levels of power. Simply put it's a street suspension that is primarily designed for a nice comfortable ride, not serious road racing. A well thought out 4 link setup for a solid axle also has the ability to dial in dynamic toe control, not just the IRS units.

 

The OEM upper control arms will fit, there is no differenece in the spacing of the pickup points, they have the same relative placement as the stock carrier.

[swhiteh3]

I've been out of this thread, and away from this board, for a few days, and a lot has happened, so let me put my $0.02 all in one E-Mail.

 

First, JWL, nice job of outlining the situation we are in. I think everyone is pulling for a good resolution on this one.

 

#1 is just flat wrong to do - we can't go back on our word.

 

#2 can create prejudices, I agree.

 

#3 would be a disaster - the rules creep will turn into a rules sprint.

 

But I'd assert we have two other options...

 

#4 Allow the Wilstone car, as noted in their logbook, to notch the frame rails, but clarify the rules to no longer allow frame rail notching. Sure, it gives the Wilstone car an advantage, but it's not a real significant one, and it keeps the future a lot cleaner for the rest of us. As for the effect on KB as a manufacturer, on one hand we owe him an apology, but on the other hand I expect the manufacturers to build parts to suit the rules, not the other way around.

 

#5 Create clear guidelines about what is and is not allowed in frame rail notching, being sure that the Wilstone car is legal according to those guidelines. We could write a rule that does not discriminate against anyone, but allows a notch of the extent and type that B&M have created. Let's measure the depth of their notch, width of their notch, and simply make that a limiter. This is where my "1/2 the height of the frame rail" suggestion came from. Give dimensions of the notch allowed, and be done.

 

You can not prejudice cars - Don't prejudice against suspension manufacturer - if KB can do it so can Griggs and MM. If they can notch for an IRS, I can do the same for a solid axle, or even for my super secret planned Swing-Axle set-up. The rule is set in stone and it's got to be the same for everyone.

 

However, the rules also need to be changed for other frame rules. Why in world do we allow frame notching for exhaust clearance or electrical wiring? I can't think of a single reason why we have these loopholes. If you seriously can not package an exhaust under the floorpan and framerails... then your car is just too damn low and completely disregards the class philosophy IMHO.

 

Just for the record, the stock IRS can be competitive using stock pick-up points. I know of stock IRS cars with legal HP/weight and only better tires than AI uses that would be on the pole of the AI races. However, this argument is just ridiculous - it's irrelevant. Let's keep our eyes on the ball folks....

[Guest]

Just for the record, the stock IRS can be competitive using stock pick-up points. I know of stock IRS cars with legal HP/weight and only better tires than AI uses that would be on the pole of the AI races. However, this argument is just ridiculous - it's irrelevant. Let's keep our eyes on the ball folks....

 

Scott, can we see those cars on a dyno? If they are what I am thinking of, SH was telling everyone his motors made way over 400hp at the wheels.....remember Chinese next week!

[RichardC]

From recent posts I would put forward an option #6:

 

The only part of the KB system in question is the upper a-arm, if Brian and Mark had used the stock piece the frame notching would not be required. Both Mark and Brian have said the only benefit is reduced weight (can't be more than a few pounds each arm) so would it be viable to allow the KB IRS with stock upper a-arms and no frame notching.

 

This seems like a fair option that would let Mark and Brian race and would not totally prejudice the KB system.

 

Richard.

[Guest]

From recent posts I would put forward an option #6:

 

The only part of the KB system in question is the upper a-arm, if Brian and Mark had used the stock piece the frame notching would not be required. Both Mark and Brian have said the only benefit is reduced weight (can't be more than a few pounds each arm) so would it be viable to allow the KB IRS with stock upper a-arms and no frame notching.

 

This seems like a fair option that would let Mark and Brian race and would not totally prejudice the KB system.

 

Richard.

 

Richard, I see where you are coming from, but at this point why not just allow the tubular arm? I honestly don't see the problem for having specific rules for specific manufactures. It's done is every other racing series on the planet.

 

If I need to cut my torque boxes out to run 38" WC rear control arms from Griggs on my TA/PB(WL) car why not allow the specific rail clearancing necessary for use of the supplied KB upper arms? KB even gives you a template on where and how much to cut. We did not follow the template, we took out much less.

 

This is the benefit of using an off the shelf system. You get all the instructions in the packet so you know exactly where and how much to take out. Remember that we are gaining safety with the notches to prevent massive metal to metal contact at full jounce. I know some may think that allowing the KB mod into the rule book is favortism but once other manufactures start making complete kits they can/will/should be subject to the same restrictions. The truth is that no one is going to move the points on the IRS so far that the KB rail mod will not work. As long as they keep the arms the same length as the OEM arms (which is not the case with most MM/Griggs cars running their front K members) there won't be an issue with making the IRS unit super tricky.

 

I would much rather use the KB upper arm for a number of reasons. I like the fact that the KB stuff has a full lifetime warranty. I like the gussets on the arm, i like the fact that the arm is 4130 ChroMoly rather than the brittle cast OEM one. I like the fact that changing bushings in the KB unit is easier and I like the small weight savings.

 

This KB IRS is really not as scary as some depicted, honestly.

[D Algozine]

From recent posts I would put forward an option #6:

 

The only part of the KB system in question is the upper a-arm, if Brian and Mark had used the stock piece the frame notching would not be required. Both Mark and Brian have said the only benefit is reduced weight (can't be more than a few pounds each arm) so would it be viable to allow the KB IRS with stock upper a-arms and no frame notching.

 

This seems like a fair option that would let Mark and Brian race and would not totally prejudice the KB system.

 

Richard.

 

This is the point I was attempting to make earlier. However, I suspect the KB system has other alterations to pick up points that modify it from a "Stock IRS". I don't know for sure, but I was just trying to read betweeen the lines of early posts. Does anyone know if this is the case? Because, if that is the case, than that is the main issue with the KB system, not an upper arm that does nothing to enhance performance.

 

Edit: Additiona thought.

Just to clarify, if the KB system is determined to be legal, I most likely will use it. Therefore, I'm not trying to get it bumped, but I still feel it should be legal, per the rules.

Edited September 21, 2004 by Guest

[Guest]

From recent posts I would put forward an option #6:

 

The only part of the KB system in question is the upper a-arm, if Brian and Mark had used the stock piece the frame notching would not be required. Both Mark and Brian have said the only benefit is reduced weight (can't be more than a few pounds each arm) so would it be viable to allow the KB IRS with stock upper a-arms and no frame notching.

 

This seems like a fair option that would let Mark and Brian race and would not totally prejudice the KB system.

 

Richard.

 

This is the point I was attempting to make earlier. However, I suspect the KB system has other alterations to pick up points that modify it from a "Stock IRS". I don't know for sure, but I was just trying to read betweeen the lines of early posts. Does anyone know if this is the case? Because, if that is the case, than that is the main issue with the KB system, not an upper arm that does nothing to enhance performance.

 

can you be more specific? the points are moved to change the roll centers and instant centers. they are not moved in/out board from the centerline of car from OEM. Moving these points is exactly what you are doing with the panhard bar, watts link, torque arm 3rd link on a solid axle car.

 

I don't know if that answered you question so let me know and if not ask again.

[D Algozine]

Brian, Thank you. Isn't the fact that these points are no longer stock open the door for many wild interpretations? That is why I, and others, are conserned about what this type of modification will lead to. As I stated earlier, hats off to you and Mark. When I looked at the KB system, I assumed it was illegal for AI. However the only way to make the the KB system legal is to write the rules exactly for the design of the KB system. That doesn't seem right and may cause many more problems going forward, as others have suggested.

See edit above - If this is legal I will most likely use. I just don't want it to open the door to huge interpretations that will lead to a money pissing match and ratical designs that will take away from the series.

[Guest]

Brian, Thank you. Isn't the fact that these points are no longer stock open the door for many wild interpretations? That is why I, and others, are conserned about what this type of modification will lead to. As I stated earlier, hats off to you and Mark. When I looked at the KB system, I assumed it was illegal for AI. However the only way to make the the KB system legal is to write the rules exactly for the design of the KB system. That doesn't seem right and may cause many more problems going forward, as others have suggested.

See edit above - If this is legal I will most likely use. I just don't want it to open the door to huge interpretations that will lead to a money pissing match and ratical designs that will take away from the series.

 

Again, when you put a panhard bar, torque arm, watts link, world challenge control arms, 3 link and various 4 link systems on a solid axle car you are changing every pickup point on the solid axle. You are doing this to improve performance. Why would you allow this for a solid axle car and not allow it for an IRS car?

 

I understand your concerns for pissing away money, but that is a fact of racing and we all have to choose how much we are willing to spend.

 

I hope to see your car with an IRS next year!

[onralz]

Brian, your continued argument seems to be that you can make a stick axle suspension handle just as well as an independent rear suspension. The stick axle doesn't have the ability to adjust camber dynamically, only statically which will hurt performance in other areas regardless of the pickup points. With an IRS with modified pickup points, spindles, and so on you can adjust the camber through bounce and jounce along with toe keeping the tire flat to the ground. It would seem that people simply don't believe it.

Hypothetically speaking, a front Mustang suspension is an IRS of sorts except it only has one lower arm instead of a lower and an upper. So for comparisons sake you think that you could put a stick axle on the front of a Mustang that would handle as well as the stock IRS front end (like is in my car)? I don't think so. (yes that is an odd comparison)

 

There is an advantage to be able to run suspension settings while the car is at ride height for turn in, and then move into different settings when the suspension compresses. That advantage is an option with a modifed IRS where with a stick axle with modified pickup points, it isn't.

[RichardC]

Was it NASA's intention to limit modifications to cars so as to keep comparable performance and hence good close racing? The alternative is to say screw the rules and use reward weight to keep everyone equal.

 

Personally I don't like the idea of reward weight as it is a pain for the competitor and a pain to manage for NASA. So the only other way to prevent "Ferrari-F1 type" dominance is to limit modifications by enforcing rules.

 

I would like to understand NASA's premise a little better.

 

Richard.

[Guest]

The stick axle doesn't have the ability to adjust camber dynamically, only statically which will hurt performance in other areas regardless of the pickup points

 

That depends on how you think of dynamic camber change. Dynamic camber change is the change in camber due to wheel travel, lateral forces or anything else that causes the wheel to move. What you are failing to see is that there actually is dynamic camber change in a solid axle car, the hard part comes with controlling it based on the design of your suspension and the construction of your axle.

 

 

 

With an IRS with modified pickup points, spindles, and so on you can adjust the camber through bounce and jounce along with toe keeping the tire flat to the ground.

 

The spindles in the KB kit are unmodified, just for clarification.

 

With a stock IRS can you can also control/adjust the camber curve, modifying the pick up points just gives you better control and different attributes (which is exactly the same reason you change the pick up points on a solid axle car). Bounce and Jounce are usually thought of as the same thing, you probably mean jounce and rebound. Toe is also adjustable in the stock IRS, but then again you can control toe (aka rollsteer) on a solid axle car with a well thought out suspension so the IRS and the solid axle are both capable of accomplishing the same things, Toe and camber.

 

Hypothetically speaking, a front Mustang suspension is an IRS of sorts except it only has one lower arm instead of a lower and an upper. So for comparisons sake you think that you could put a stick axle on the front of a Mustang that would handle as well as the stock IRS front end (like is in my car)? I don't think so. (yes that is an odd comparison)

Yes, this is a very odd comparison.

 

There is an advantage to be able to run suspension settings while the car is at ride height for turn in, and then move into different settings when the suspension compresses. That advantage is an option with a modifed IRS where with a stick axle with modified pickup points, it isn't.

You can do just what you mentioned above, but it takes a very clever design that is not currently employed in AI.

[RichardC]

Brian,

 

Personally I believe none of us want AI to get to a position where everyone has to run a KB IRS to be competitive. (I'm sure KB would love it).

 

You have run stick and now the IRS and after Mid Ohio you commented on how good it felt. At your second race weekend you won Saturdays race (well done by the way). That is remarkable for a brand new race car, 99% of cars are not competitive for many of their first races.

 

I know it's a very short time but there is the possibility that with more track time and tuning your car might run away with the championship.

 

Should you be penalized for that? Tough question but the problem is if the KB IRS proves to be far ahead of everything else on the track we have no alternatives. You keep talking of some super special stick axle setup but the current off the shelf setups cost about the same as an IRS (the IRS is a bolt in, the stick setups require welding). A custom setup would far exceed those costs.

 

I'm all for raising the bar but it has to be done under some form of control or the series will die.

 

Richard.

[onralz]

That depends on how you think of dynamic camber change. Dynamic camber change is the change in camber due to wheel travel, lateral forces or anything else that causes the wheel to move. What you are failing to see is that there actually is dynamic camber change in a solid axle car, the hard part comes with controlling it based on the design of your suspension and the construction of your axle.

 

That's the key, controlling it. It is also far more limited in a stick axle than in an IRS which goes to show my point that the IRS is a superior suspension over the stick axle which requires more compromise than an IRS.

 

With a stock IRS can you can also control/adjust the camber curve, modifying the pick up points just gives you better control and different attributes (which is exactly the same reason you change the pick up points on a solid axle car). Bounce and Jounce are usually thought of as the same thing, you probably mean jounce and rebound. Toe is also adjustable in the stock IRS, but then again you can control toe (aka rollsteer) on a solid axle car with a well thought out suspension so the IRS and the solid axle are both capable of accomplishing the same things, Toe and camber.

 

Sure you can change them on a stock IRS. So why do you keep calling the stock IRS uncompetitive? In a stock one, you are limited by the pickup points, and frame rails. In a stick axle, you are limited as to how much camber and toe you run which has to be a compromise as unlike NASACAR, we turn right too. When allow the frame rails to be cut, and the mounting points to be moved, you take out compromise.

Thanks for the clarification on the jounce and rebound. So in other words the stock IRS, the stick axle, and the KB IRS are all able to control the same things. So the key point is that the stick axle and stock IRS has limits that they KB IRS doesn't have as I mentioned earlier. The lack of limits is what concerns me.

 

I can't believe you don't like my comparison. Other than the fact that they do double duty by turning, it is actually a fair comparison.

 

You can do just what you mentioned above, but it takes a very clever design that is not currently employed in AI.

 

Yes you keep saying it can be done. I've spent many many weekends up at Hoerr racing (the build transam cars, and Grand Am cars) talking with their designers about what "can be done" with a stick axle. Their argument is the same as mine is. The stick axle is all about compromise. Sure there are things you can do to achieve a small amount of camber, toe and so on. You can't change it like you can an IRS. If you have the IRS limited to certain parameters, than you again work with compromise. When the IRS doesn't have parameters like pickup point, mounting points, frame rails, spindles, etc, there isn't any compromise which essentially make the aftermarket companies that build stick axle suspensions and have supported AI for years, uncompetitive. It certainly takes out the people like me who build their own suspensions because of cost out of the mix essentially raising the bar and adding costs to the series. If someone wants to raise costs, go to a pro series.

 

It's kind of funny that a while back, "someone" made statements basically stating that I was trying to kill the KB IRS. Hell, if anything, I am selling it for them.

[D Algozine]

I understand your concerns for pissing away money, but that is a fact of racing and we all have to choose how much we are willing to spend.

 

This type of statement is very disturbing to me. This is not what club racing is about. That sounds like a pro series.

Mark L. makes some very good points.

Does anyone really believe that an unlimited, modified and sorted solid axle is equal to an umlimited, modified and sorted IRS? That is insane. Marks points about limitations and compromises are right on.