sjfehr

NASA has picked up autocrossing; it's only in a few areas right now, but they're trying to expand. I run with NASA Mid-Atlantic a few times a year and like some aspects of their classing, but since the classes are built off road-race classing, it doesn't always carry well into autocross or between completely disparate cars that end up classed together.

http://www.get-fast.net/nasacross/

Audii-Dudii

If you're looking at the proposed Street Class rules as the SCCA's attempt at addressing the current gripes of Stock-class competitors, then I can certainly understand why you're not in favor of it. However, if you look at the SEB's proposal as the SCCA's attempt at reworking the basic structure of the rules to insure that autocrossing will continue to be fun for future Stock-class competitors -- which is clearly the goal the SEB is kicking at -- then I think it has considerable merit, because the operational characteristics that make cars fun for people like us to drive at autocross events are, for the most part, exactly the same ones the government is intent upon regulating away in the name of making cars safer for everyday street use by average (and let's face it, less than average) drivers.

For instance, I believe that oversteer is now on the automotive equivalent of the endangered species list. There will come a time in the not too distant future when it will be difficult, if not outright impossible, to make all but the most expensive "sporty type" cars spin and/or slide their rear wheels (if only because RWD is on the endangered species list as well). Heck, I suspect there will come a time in the not too distant future when it will be impossible to make a car spin and/or slide any of its wheels, period. And speaking for myself, much of the fun of autocrossing is making my car do what I want it to do, when and how I want it to do it, not necessarily achieving the quickest time around the course (although if I happen to win my class at the same time, then so much the better!)

Sure, the immediate effect of the SEB's proposal will be to upset the current status quo for many cars and the classes in which they compete, which sucks for the competitors who draw the short straw. In the longer run, however, the proposed structure insures that competitors will have the allowances they need to make their cars fun to drive without having to dedicate them to autocross use only. Just as today's rules provide a class for most cars on the road, but don't guarantee they will be competitive in that class, I see the proposed rules as providing a way to make very lightly modified cars fun to autocross, but don't guarantee they will be competitive in whatever class they run. I don't know about you, but I don't autocross solely for the competition aspects: If/when autocrossing my car is no longer fun, then I'm gone, whether I'm winning my class or not.

Yes, as it happens, I do have a vested personal interest the proposed Street Class rules because they will allow me to address most of the design compromises Porsche made that make my Cayman S less fun to autocross than it would be otherwise and also more competitive as well, at least in its present class. But there is no guarantee that my car will remain in AS going forward or that other cars won't be shuffled into AS so as to relegate it to "has been / also ran" status at some point in time. Either way, though, it will still be more fun to autocross than it is now and that alone improves the odds of keeping me around for the future.

When you seriously ponder the issue, trying to balance the interests of current competitors, who have already voted with their wallets, while at the same time making the sport attractive and accessible to newcomers, who have yet to do so, is quite a challenge. And quite frankly, if a newcomer to autocrossing expects they can buy a car off the dealer's lot, drive it straight to a parking lot across town, and immediately start winning autocross events with it, then I'm afraid they're going to be sorely disappointed regardless of the rules under which they're competing. Taking all of the above into consideration, to which of these two groups would you have the SCCA cater?

Overall, I believe the proposed Street Class rules are a logical, well thought out step forward. Yes, the transition to them from the present rules will absolutely cause a considerable amount of disruption to the status quo (just as this country's change from capitalism to socialism is causing considerable amounts of disruption in other quarters <he types, ducking>), but for the SCCA to do nothing will eventually cause a considerable amount of disruption of another, much less pleasant sort, which is when they stop holding events because no one shows up...

Bottom-line: I believe the way forward is to adopt the proposed Street Class rules and deal with consequences of it by shuffling the classification of cars that pose problems because they're overdogs or underdogs in their initial classes. I mean, we already have Corvettes competing against Lotus Elises, so really, how much worse can this get?

Yes, I personally would be very happy competing in just such a class as you have proposed. Heck, I would be almost as happy just being allowed to compete in STR with my Cayman S, but one step at a time, right?

ToSi

This is just wrong - the writers of the proposal have a very circa ~2005 mindset. Folks involved in the industry will tell you that anything with sporty pretensions these days is actually developed w/ performance use in mind. While initial ESC systems were hyper-aggressive, the latest trend is actually to use the stability control systems to enable more aggressive base chassis tuning.

here's an example, from: http://www.caranddriver.com/comparis...ocus-st-page-3

"But it’s at the adhesion limit where the Focus ST reveals its most endearing characteristic: lift-throttle oversteer. When you sense the front tires slipping wide, a quick reduction of go-pedal pressure remedies the situation. The tail steps out smartly but never excessively, your arc tightens, you kiss the apex and exit the corner on the most expeditious line. Ham-handed operators will surely be intimidated by the two-axle steering, but any driver with a lick of ability can make the ST dance..... A stability control switch in the center stack allows you to select either a sport mode or an off position. And when you choose “off,” this stability control remains delightfully disabled. "

Again, sounds like a limited-prep ST-like class is what's missing.

Agree that most new guys show up w/ a few poorly thought-out, yet forum-approved modifications that put them in an unrealistic class. "Stock" is where folks who have been down that path & know better go. It should stay that way.

Audii-Dudii

Based upon my limited experience with current generation cars, I don't completely disagree with you, at least insofar as cars with "sporty pretensions" are concerned, but for more mundane cars that are lacking "sporty pretentions," I will disagree. And even at that, the stability management / traction control systems that are installed on many cars that do have "sporty pretentions" -- surely my '06 Cayman S qualifies? -- severely neuter their autocross performance and most decent drivers will perform better with it turned off. I certainly fall into that category, as I find the car almost impossible to drive quickly with it turned on, and (again, based upon my limited experience) it's less intrusive than similar systems found in other cars, so I can well understand the benefit of being allowed to disable it...

Replacing both front and rear a/r bars, using camber plates and/or crash bolts to achieve more negative camber, and being able to upsize / downsize wheel diameter each address issues that some cars have and others do not, which I believe will serve to equalize the performance of the cars in any given class (which, I admit and accept, may well not be their present class) and also make it possible to keep cars compeititive for a longer period of time, all of which I personally view as a net plus.

Maybe, but why create yet another new class when revamping an existing class can accomplish essentially the same thing?

Personally, I don't understand why so many people find it such a burden to have to work on their car (or pay others to work on it if they can't or won't do it themselves) in order to realize its full potential. Do people honestly expect an inexpensive or off-the-shelf anything to be competitive in any sport? And if they do, should the SCCA really cater to them at the expense of those who understand and accept this concept? (When I was younger and raced sailboats and bicycles, setting up one's equipment properly was at least as important as it is in autocrossing, especially in sailing's spec classes, but this was seen as part of the fun, not a problem that needed to be addressed.)

Fwiw, after completing my first event in 1988, I immediately realized that it was necesary for me to buy a second set of wheels and A-008R tires to be competitive; by the fourth event, I had also put a round of shocks on the car. As I recall, it never crossed my mind to complain about this as somehow being unfair or burdensome (and believe me, money was tight for me back then!) or to suggest that it needed to be changed or I would quit ... times have changed, eh?

balefire

after a lot of thought and reading about the STREET proposal...

I still like street tire limitation and camber allowances.
but
I think the wheel diameter could be limited to <=15" can +1", >=19" can -1"
one swaybar allowance is probably safer than 2
single adjustment shock is better than 2
ECU stock until there is a better way to police it.

Audii-Dudii

When you say "one swaybar allowance is probably safer than 2," do you mean in terms of actual safety or playing it safe with respect to performance potential? If it's the latter, then what's the big deal ... a/r bars can be had off the shelf for almost any car for less than $500 each (and usually much less) and if it's the former, then allowing competitors to install a balanced pair of a/r bars makes more sense than allowing them to install only half of a balanced a/r bar package.

And aside from Bilstein, which makes performance-oriented shocks that are non-adjustable, which company (or companies) these days makes a "single adjustment shock" that even a casual autocrosser would consider installing on their car?

If your concern is that the proposed changes will upset the balance of existing car classifications too greatly, I certainly understand, but the reality is that even the most minor rule tweaks will have the same effect in one class or another (the autocross equivalent of the "butterfly effect"!), so in order to move forward overall, we (all of us, collectively) have to get past the idea of preserving the status quo and address issues of car competitiveness / class structure as they shake out over time.

Personally, I'm very much in favor of the proposed Street Class because it will make my car more fun to drive while remaining eminently "streetable." Yet at the same time, I know there's a good chance that the new class rules will ultimately work to my detriment if I'm forced to compete against Z06 Corvettes with my Cayman S by moving them down to AS or my Cayman S up to SS ... and thus it ever was.

PedalFaster

The big deal is that serious competitors won't (and won't be able to, if they want to stay competitive) limit themselves to off-the-shelf bars. Opening up both sway bars will prompt people to get gargantuan bars custom made. On the other hand, limiting the bar allowance to one end of the car is inherently self-limiting, since you can only put on so much bar before the car becomes unbalanced. For almost all cars, the one bar rule self-limits to a size that's commonly available on the aftermarket, keeping expense in check.

Audii-Dudii

Well, if you understand how a/r bars work, then you also understand there is already an effective limit as to how much additional rate a/r bars can add in roll (i.e., they can at most double the existing spring rate). And that limit will be reached well before the bar becomes "gargantuan" in size (unless you count its effect as ballast, in which case, the bigger the better!), so the apparently widespread concern that people will ultimately end up running the same effective spring rates in roll that they do now with stiffer springs in the ST classes via custom, gargantuan-sized a/r bars is comletely unfounded. The same mostly holds true for the notion that in order to make effective use of these new, larger, stiffer a/r bars, new matching shocks will also be required; in some cases, Yes, this may indeed be true, especially if the shocks are OEM, but in most cases, the existing shocks should work well enough.

As for limiting the a/r bar allowance to only one end of the car, many (most?) a/r bars are sold in pairs, so many competitors will end up buying both bars even if they only use one, which seems sort of silly. And because a/r bars are typically available off-the-shelf for most cars and are reasonably quick-and-easy to install (except for the Cayman's front bar, of course!), why not allow people to use both, as is commonly the case for cars that are driven regularly on the street, rather than force them to (once again) resort to extreme measures and create radical, autocross-only solutions to what are common problems in order to workaround an artificially and illogically restrictive set of rules?

Bottom line: As I understand, one of the fundamental purposes of creating the proposed Street Class is to bring autocross back into the real world from the cloistered and increasingly out-of-touch world where it has lived for the past 40 years or so. If the net result of a two-bar allowance is to make some cars more or less competitive than they would be otherwise, then so be it ... shuffle them to another class so the competitive balance is restored and everybody lives happily thereafter with cars that are more fun to drive whenever they are driven.

NJ-GT

Remember to submit your letter to:

www.sebscca.com

Title of Request: Street Category.

I personally submitted a letter of support.

Stock is designed to be the entry level class for SCCA AutoX, it is in the rulebox. Then comes ST, then SP, SM, Prep and Mod. There is an excessive number of classes that require race tires, and just a handful that require street tires. There should be a balance.

The ST classes have a gigantic list of cars excluded from running in them. Every year more cars show up to the market and get assigned to a Stock class, but not to a ST class. ST cars don't make daily drivers, these cars are running stand alone ECU, stiff springs, lightweight racing seats, etc.

I like the following ideas for the Street Class:

- Limiting any sway bar to just one axle
- No camber allowance other than stock settings
- Non-remote reservoir shocks (they add springs if you play with canister pressures), and up to 2 adjustments
- Wheels < 16" + 1" and > 18" - 1".
- No ECU tuning (this is getting harder to police, I saw a guy with a remote download a new tune 50ft away at an SCCA event)

Using the 0.975 factor to differentiate lap times with AutoX race tires and fully legal street tires, the difference is just 1.25 secs on a 50 secs course. I have observed similar results (A6 vs. many flavors of street tires) in my 996GT3, 997GT3RS, Cayman and Fiat.

I corded my RE11 two weeks ago, over 15,000 miles, autoX, DE, NASA Time Trials, and almost 4 years on them, saved a bunch of gas money, tire money and 3-4 hours per day not having to load/unload/store the trailer twice per day.

I prefer a 26mpg trip with a helment/tire inflator/perssure gauge, than my 10mpg trip with the tow vehicle, trailer, gear, car on the trailer, and the time hassle, for just three 50 secs laps.

PedalFaster

Your point about sway bars' contribution to spring rate is interesting, but your conclusion ("that limit will be reached well before the bar becomes "gargantuan" in size") is incorrect. How do I know? Because, like all other Stock class S2000 owners, I'm *already* running a gargantuan front sway bar (1.375") even though I'm not allowed to touch rear bar. I can't say for sure whether I'd be able to go with a yet bigger front bar if I also got to change my rear bar, or if a gargantuan rear bar would work on my car, but the odds would be pretty good.

Did I mention that my front sway bar cost over $1000 as-is?

One thing I suggested while corresponding with my friendly neighborhood SAC and SEB members was limiting sway bar diameter to something non-gargantuan, like 1", or the OEM diameter, whichever was larger. Allowing bars that size on both ends of the car would still introduce a lot of tuning headache, but it would at least keep things non-ridiculous (and reduce the need for custom bars costing four figures).

Audii-Dudii

Personally, I wouldn't consider a 1-3/8" bar to be "gargantuan" -- in a past life, I've actually used a larger (1.5") one! -- but this brings up a good point, which is that one cannot judge an a/r bar's stiffness by its diameter alone. Its width, the number and radii of any bends, the length of the arms, and the location of the mounting points on the chassis all play a role as well, so if you have long arms on a 1-3/8" bar that has a few bends in it, then it may well be softer in situ than a straight 1" bar with short arms. Accordingly, any attempt to impose a limit on the stiffness of an a/r bar by enacting a rule that restricts its diameter alone can easily be worked around by someone who is willing to pay for a custom, one-off design...

In view of the above, I have no idea whether the 1-3/8" bar on your S2000 is truly stiff or not at all. That said, though, I suspect it's more stiff than soft, and as such, I would not be surprised if you find that swapping to an ever larger bar still will not have nearly as much effect as swapping to this bar from the original one did...

BTW, this same basic effect also occurs with springs. I had a friend who many years ago autocrossed a DSP Pinto (don't laugh; it was actually quite quick and a hoot to drive!) and when he swapped from 600 lb front springs to 1000 lb springs, he found this had no effect whatsoever on the car's behavior. This is because the chassis was so flexible, that once the spring rate exceeded 600 lbs, the chassis would twist before the springs would compress!

As explained above, any attempt in the rules to restrict the stiffness of an a/r bar by limiting its diameter is effectively no restriction at all. Possibly this could work if the bar must also maintain the same dimensions as the OEM bar in all other respects, but there are many cars where such a restriction will prevent any but an OEM bar from being used because of space limitations, which is counter to the point of having the allowance in the first place...

Allowing only one a/r bar to be changed instead of both will definitely limit how much of an increase in roll rate can be tolerated without upsetting the balance of the car, but I'm not sure it will save much money. As I noted, many bars are sold in pairs, so many people will have to buy both even if they only use one. Also, many serious competitors will no doubt buy bars for both the front and rear and then experiment to see which one works best for their purposes ... in either case, no money has been saved, so what was the point? <shrugs>

P.S.: It's not relevant to this discussion, so I won't digress, but my analysis of a sway bar's contribution to spring rate is not wrong. Think about it: If one end of the bar is clamped solid, as Porsche did when it used torsion bars instead of coil springs, then a bar's inherent stiffness does matter and a larger diameter bar will have a higher spring rate than a smaller diameter bar. In the case of an a/r bar, however, one end is not clamped solid but is pushing against a spring. In effect, it allows the spring on the outside of the car, which is being compressed by the loads fed into it, to resist these loads (hence compress less) by "borrowing" some of the energy from the spring on the inside of the car, which is extending, and this energy is then transferred to the outside spring via the a/r bar. If the a/r bar was perfectly rigid, then all of the energy from the inside spring would be transferred to the outside spring and therefore this sets the upper limit for how much additional roll resistance an a/r bar can contribute. If the a/r bar is not perfectly rigid (and none of them are!) then some portion of the energy from the inside spring is used to twist the bar instead of being transferred to the outside spring, so the additonal roll resistance contributed by the a/r bar is less than 100%. By changing the design of the a/r bar (diameter, arm length, etc.), one is changing the extent to which the bar twists and in turn, how much of the inside spring's energy it transfers to the outside spring.

abqautoxer

Interesting thoughts.

Yes I'm here, just lurking as usual.

kjchristopher

The bigger the bar, the more the suspension will act like a solid axle. You'll get good initial response and poor handling as you go skidding around corners. Those who understand vehicle dynamics won't be going to tree-size bars. At least, not for long.

PedalFaster

Personal definitions of "gargantuan" aside -- 1 3/8" is far larger than most off-the-shelf sway bars marketed to non-racers, meaning that most people wanting to run bars this big will have to get them custom built or from a race shop. Either way, they'll be pricey. Also, I know from firsthand experience that a bar that size will tear through sway bar mounts with some frequency, which requires either replacing sway bar mounts with some frequency, which I don't think is good for the class, or buying custom beefy mounts, which will again be expensive.

That's a bizarre assertion. "No restriction at all" implies that it's possible to create an infinitely stiff anti-roll bar of any arbitrary diameter, which is of course not correct.

Understood that a bar with short, straight arms will be stiffer than a bar with long, bendy arms, but that point is orthogonal to mine about limiting bar diameter -- a 1" bar with short, straight arms be still be softer than a 1.5" bar with short, straight arms.

Many bars are sold singly. Your point?

I didn't say it was wrong; I said that Stock competitors can and already do mount massive sway bars, and allowing them to modify both bars will make doing so attractive to people for whom it's not feasible under the current one bar allowance.

PedalFaster

To clarify, I assert that it would be bad for the class if custom / race sway bars became commonplace, as custom / race bars tend to be significantly more expensive than off-the-shelf pieces. Right now many / most Stock competitors run off-the-shelf bars; from what I've seen, it's mostly because they can't run a larger bar without skewing the handling balance of their car too far towards understeer or oversteer. (My car, an S2000, is an exception to this rule.) Allowing competitors to change both front and rear bars will increase the likelihood of people being able to mount larger-than-off-the-shelf bars on one or both ends of their cars, which will in turn increase expenses.

Agreed that there's such thing as too much sway bar, but that has no significant bearing on my concern, as you can go considerably stiffer than off-the-shelf sizes (and thus have to spend on custom / race parts) before you reach a point where excessive sway bar stiffness hurts more than it helps.