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Below is a copy of a letter I sent to the SEB regarding stock classification.  I figured I would post it here so you all could send your opinions to the SEB also.  Some of you might consider this a simplistic approach and that is the point.  I am hoping to simplify the decision making process and make it clearer for everyone. 

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Open letter to members of the SEB and SAC regarding car classification for stock classes:

 

I would like to offer my opinion and a potential solution to all the perceived confusion on car classification for the stock classes.  Let me start by saying that I have only competed in stock classes for the past year but I have over 15 years of autocross experience in Street Prepared.  I intend to continue to participate in stock classes but I have yet to determine what class(es) I will be in since I do not currently own a car that would meet stock class rules.

 

I have been following a lot of the discussion regarding the classification of DS, GS, and HS cars and a little bit of the discussion regarding some of the other stock classes.  The one underlying thing that keeps coming to my mind is that everyone seems to want some sort of consistency regarding classification.  Yes, some want their cars moved, and some want others cars moved but I think most of the membership just wants to know that their car is in a particular class, to understand why it is in that class, and to know that their car will remain in that class.  I think if we can achieve this, then much of the discussion on car classification would go away.

 

In my opinion, the current method of car classification is broken.  It is my understanding that we are classifying cars based on performance potential.  This term, “performance potential” is vague and open to many different forms of interpretation.  We all have seen that we can not determine the “performance potential” of a car until someone has fully developed a car within the limit of the rules and a national-caliber driver is actively campaigning the particular car.  If we are classifying a car before it is fully developed within the rules, at best, this becomes pure guesswork.  

 

If we were to begin the whole car classification process with a set of criteria that is applied to each car, it would be a good start.  These criteria would have to be something that is known by everyone and, preferably, would be printed in the Solo II rulebook. 

 

This is purely for example purposes but let’s take DS, GS, and HS since they seem to have the most discussion and the cars seem to be very similar.  It would appear that for the most part we already have an underlying criteria for each class.  HS appears to be relatively low performance, comparatively speaking, economy based cars that are very high in production numbers and relatively low in initial purchase cost.  GS appears to be medium performance, slightly more expensive and possibly slightly less plentiful cars than what is currently available in HS.  DS appears to be higher end, mainly FWD cars that have specialized equipment geared towards the automotive enthusiast.  DS cars, in general, seem to be lower production number and higher cost cars than GS and HS.  I hope we all agree on the “underlying criteria” fact.

 

Now, if we were to take this one or two steps further, I think it would help clarify things with the membership and make classification easier for those who have to make the decisions. 

 

The first step would be to refine what we already have as “underlying criteria”

by identifying specific items that we would use to classify cars instead of the existing grey area of “performance potential”.  In my opinion, we could use specific items to look for that the potential stock class car comes equipped with.  HS would be low horsepower, cars (possibly 140 hp or less) equipped with open differentials, and having no adjustability for camber in the front.  GS would be slightly higher horsepower cars (possibly 120-180), with open differentials, and having the possibility of camber adjustment through factory authorized means.  DS would be high horsepower cars (possibly 160+), likely with a limited slip or with the option for one from the factory, and likely to have adjustable camber from the factory.  I think this would work for the FWD cars in the classes.  If you wanted to classify AWD and RWD cars in these classes, as we do now, you would probably want to use a slightly modified set of criteria for AWD and another set for RWD which would tend to keep the playing field level between the different drivetrain layouts that are in one class together. 

 

The next step would be to print all of these criteria in the Solo II rulebook.  That way, the membership understands, not only why their car is classed the way it is, but what cars will be coming to their class in the future.  This would be useful not only on the national level but probably more so on the local level.  I can’t tell you how many times a new person has come to me to ask why their car is classed against car X where it can’t possibly compete.   With a set of criteria printed in the rulebook, I could take it to them and say, “Your car is classed based on the fact that it makes 140 horsepower and has the capability for adjustable camber and has an open differential.  The other cars in your class also meet this criteria.” 

 

Obviously, you could pick any criteria you would like to use for each particular class.  You don’t have to use what I have used above.  However, if you determine a set of criteria to use and stick to it, I think you will help eliminate a lot of the confusion on where cars are classed and when they are moved to different classes.  You will also have progression in the classes since car manufacturers are constantly improving their cars and the newer models tend to perform better than the older models.  Additionally, if something in the way the manufacturers equip their cars changes (such as if they discontinued the use of limited slip differentials on FWD cars) you can always change the criteria for those classes that would be affected.  This would be similar to the occasional stock class realignments we have had in the past. 

 

I hope you will approach this proposal with an open mind and give it some serious consideration.  I think it will help the membership by having a more detailed description on how cars are classed.  It will also help you, the rule makers, by simplifying the decision making process and allowing you to concentrate on other issues that may need to be addressed.  Finally, it could possibly help our relationships with the manufacturers by letting them know how cars are classed and eliminating any perception of bias toward or against any manufacturer.

 

Sincerely,

Mark Pilson

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Mark Pilson
owner of STS2 Honduh
co-driver of ES Miata (race tires rule)

I like the basic idea. I would change the HP ranges to power to weight ratio however. A 3500 lbs car with 200 hp is not going to be competitive with a 2500 pound car with 200 hp no mater what else it has. I also think the camber adjustment should be quantified by how much adjustment exists, more or less than 1.0 degree for example.

You might even be able to come up with a points type formula that could class all cars in stock.  There could be several catagories.  Power to weight, wheel width vs. weight, amount of negative camber achievable, drive type, suspension type etc.

Power to weight:

8 lbs/hp or less =10 point, 8.01 to 9.0 = 9 points, 9.01 to 10.0 = 8 points, ect.

Wheel vs. weight (weight divided by total of all 4 wheels added together):

60 or less lbs/in = 10 points, 61 to 70lbs/in = 9 points, 71 to 80 lbs/in = 8 points, etc.

Camber:

more than 2.0 degree negative in front and rear = 10 points, more than 2.0 front and 1.0 to 2.0 rear = 9 points, more than 2.0 front and less than 1.0 rear = 8 points, more than 2.0 front and none rear = 7 points, 1.0 to 2.0 front and rear 6 points, 1.0 to 2.0 front and less than 1.0 rear = 5 points, 1.0 to 2.0 front and none rear = 4 points, less than 1.0 front and rear, 3 points, less than 1.0 front and none rear = 2 points and none front or rear = 1 point.

Drive type:

AWD = 10 points, RWD = 8 points and FWD = 6 points

Suspension Type Front:

Double wishbone =10 points, Short Long Arm = 8 points, Struts = 6 points, live (solid) axle = 4 points 

Suspension Type Rear:

Same as Front

Vehicle Size Perimeter distance in feet:

 34' and less = 5 point, 34.01 to 37' = 4 points, 37.01 to 40' = 3 points, 40.01 to 43 = 2 points, 43.01 to 46' = 1 point, over 46' = 0 points.

So on this scale an '04 Z06 would get the following score

P/W = 10 points, W/W = 10 points, Camber = 10 points, Drive Type = 8 points, Suspension = 20 points, Size = 3 points total = 61 points.

So maybe SS would be 60 to 65 points, AS = 55 to 59 points, BS = 50 to 54 points, CS = 45 to 49 points, DS = 40 to 44 points, ES = 35 to 39 points, FS = 30 to 34 points, GS = 25 to 29 points and HS = less than 25 points.

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Mike Minear

BTW, I guessed some of the specs on the Z06, so if my point total is aff a bit, correct me and let me know what is should score.

My wifes '01 Trans AM, currently and FS car, would score 35 points.

How would your car score?

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Mike Minear

Hmmm, my Cooper (not S) scores 29...  (edit  33 with size)

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Keith
'90 Miata with a really big roll bar
chaserace.com
tightntidyracing.com
jimsdetail.com
vorschlag.com

You need to take into account size. A narrow car often has an easier time on smaller courses.

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Polo Green 95 LT1 6-spd Chevy Corvette
Upgrading as stuff wears out and/or breaks
Autocross / Road / Drag in whatever class they decide to stick me in this week!
2000 CCM Group IIG Autocross Champ
Member: NCCC, NCM, SCCA, NHRA, CART

Your right I forgot that one, we need a way to rank dimensions. Narrow, short cars have an advantage in all slaloms, not just tight courses. I'm not sure it should carry much weight as some of the other catagories however. Maybe we can use perimeter distance around the car, Lx2 + Wx2 = Perimeter. If a mini is say 12'x4' (guessing) you get 32' perimeter, an old Town car is about 22'x6' = 56'.

So, 34' and less = 5 point, 34.01 to 37' = 4 points, 37.01 to 40' = 3 points, 40.01 to 43 = 2 points, 43.01 to 46' = 1 point, over 46' = 0 points.

Add 5 points to all class point ranges.  I've made the changes above.

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Mike Minear

What would an "S" score?

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Mike Minear

A top of the head calculation found me at 49 for the Elise....B-Stock? I guessed at camber points though...it can hit about .6-.7 up front and mid 1s out back = often used. It's got a peaky motor (with sweetspot MPH ranges), is not long and the brakes are very good.





Seems like gearing/powerband type factors could be formula-ized, along with length / width dimensions. Cubic inches are a powerband factor. Keep length and width separate...consider wheelbase / overhang? Braking ranges. Tire capacity and availability of top choice brands. Fudge factor aka competition adjustment?

I'd imagine that course dependencies could get tricky as we are just adding up points, yet the mix matters.

Wheel size covers tire capacity IMO and availability is a non issue. If it comes with 19's, your gonna end up in SP so you put 18's on it anyway.

Gearing and power band is interesting, any suggestions on how to score that? What about engine location, Front/ mid/ rear? Or maybe weight distribution would cover that well enough?

From what little I know of the elise, I get 56 points, AS on my scale.  I used the Z06 as a bench mark for SS to start the scale, but the ranges are off the top of my head and could definately use refinement by people that know the bench mark cars of other classes better than I.

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Mike Minear

00 SS wrote:

What would an "S" score?

Cooper S  = 36...

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Keith
'90 Miata with a really big roll bar
chaserace.com
tightntidyracing.com
jimsdetail.com
vorschlag.com

I don't think static camber is a good parameter...the Elise may "only" get -.7 or so on the front, but with the favorable camber curve of the design, it is not at all like a MacStrut type design where you start with little and end up with nothing!

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In slow, out fast.
In fast, out backwards.

The Elise has MacStruts? On both ends?

That's good input about the camber curve. How, specifically, would you modify the catagory and scoring? Do you like the general idea of a points system like this to class new cars? I just made this up in about 10 minutes this afternoon, I wasn't trying to be precise at all, just trying to outline the idea.

Also, we need and LSD yes or no catagory.  LSD = 5 points per diff, no LDS = 0 points per diff.

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Mike Minear

00 SS wrote:

The Elise has MacStruts? On both ends?

 

No, the Elise does not struts, that's what I was trying to say: different suspension designs will have different needs for lots of static camber!

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In slow, out fast.
In fast, out backwards.

Certainly I think this discussion is great and maybe it will lead to a better classification system.  However, this points system seems very complex.  Do you think we could simplify it?

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Mark Pilson
owner of STS2 Honduh
co-driver of ES Miata (race tires rule)

I think there's some "fudge factor" you have to throw in. Certain cars are simply better than the sum of their parts, and it's awfully hard to quanatatively take that into consideration...on the other hand, some cars are less than the sum of their parts. With all the characteristics of a car that can help/hurt it on an autocross course, it makes it awfully hard to put a number to that.

Obviously, just like now, we'd have some cars that are simply overdogs/underdogs in their class. Which will beg the question, "why can't we move them up/down into an appropriate class?"... and that puts us right back where we are now.

I like the concept of the idea, but I don't think a points system is the way to do it. Wish I had a better idea...

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Jesse
-2002-2006 E-stock 93 MR2 (sold)
-2007-2008 XP Spyder