Improvements for CDC Indexing for 2009

[echan]

I heard several different members talking about the current 2008 index system, the old 2007 index system, and the small bore class. Some of the comments included:

1. Some liked the old 2007 indexing better because it gave the newer drivers more of a feeling of accomplishment as they improved.

2. Some are surprised that it appears that some participants are not truthful when entering their indexes in the system. (I've noticed that this year, several people have started nit-picking what people have on their cars. I'm not sure this environment is very heathly for a club trying to focus on "fun").

3. Some liked the Small Bore Series Concept and thought is the most fair. However, if the concept is trying to have a low cost class that most can afford, why allow r-compounds? If only we only allow street tires, the cost would be even more affordable. (I personally think that we would then get into debates on what tires should be considered street tires, like the Bridgestone street tires that are as sticky as V710 (and cost as much).)

Here's your chance to weigh in on what you think we do to improve the indexing for 2009.

Thoughts? Comments?

Ed

[FredK]

I think any sytem will have problems, and someone will think it is unfare. I liked the old system, I like the new.

Pointing out that someone is running on R-compound when they forgot to mention it is not nit picking, especially when it puts them ahead of many people, me in particular.

I think the penalty for tons of HP is to much, on the small CDC courses no one can use that much power, anything over 250 RWHP should have the same index.

Anyone who is FTD everytime they show up should be banned.
FredK

[smetzger]

I think any sytem will have problems, and someone will think it is unfare. I liked the old system, I like the new.

Pointing out that someone is running on R-compound when they forgot to mention it is not nit picking, especially when it puts them ahead of many people, me in particular.

Agreed

I think the penalty for tons of HP is to much, on the small CDC courses no one can use that much power, anything over 250 RWHP should have the same index.

Anyone who is FTD everytime they show up should be banned.

I hope you missed the smiley on that. IMO, banning should be for something more serious like starting a fight, drinking alcohol, burnouts in the pits, etc.

Most of the top 10 indexed times are high end cars or highly modified cars. I don't know if that's because better drivers invest more money and time, or because a better car makes a better driver.

What would be interesting would be to see an SCCA index, with two categories Street Tire and non-street tire. I am not saying we should use the SCCA index. But it would give us a point of reference, because I have no idea if the index multipliers are anywhere near fair.

[Tedzilla]

You missed Fred's humor... FTD means Fastest Time of the Day.
SCCA has street tire classes. The meaning of street tires is a problem. The fastest street tires are better than 2nd rate R compounds. I run Toyo R-888 (R-comps) as my daily driving tires and Hoosier A6s for autocross on my M-B 190E so R-888s really are street tires in my case.
As it stands the current index is dominated by highly modified cars and if the index isn't changed no car legal for SCCA stock has a chance. I've been driving a stock legal Boxster and don't usually lose to genuinely stock cars. If I felt the need I could lighten the car from 3100+ lbs to 2500 lbs, install full race suspension, carbon fiber body panels with flares to fit 345 width R-Comps and limited slip differential without changing my CDC index...
SCCA's index isn't perfect but it's more fair to non-racecars.

Ted

[BrianK]

My opinions in order of personal preference:

1. Just go SCCA PAX and call it a day. One multiplier to figure out and that is it... It will be the most fair.

2. The '08 system isn't bad, but I think it could be refined further if it's kept in place. Even though I don't run street tires, it seems like the street tire guys are at too much of a disadvantage. I believe the R-comp multiplier should be bumped up to close the gap and give them more of a chance. I also agree with Fred that anything over 250 whp isn't going to help on a CDC course. There are also a number of cars out there that struggle to put down 100 whp so I think you should add a multiplier for them. As for weight, I think the current multipliers are decent. So if you want to refine on the '08 system I believe the following (IMO) will help even things out a little further:

Tire Multiplier
Street Tires = 1.00
R-Compounds = 1.04

Horsepower Multiplier
Below 100 hp = 0.99
101 hp to 150 hp = 1.00
151 hp to 250 hp = 1.01
Over 251 hp = 1.02

Vehicle Weight Multiplier
Vehicle weight < 2000 lbs = 1.02
Vehicle weight 2000 to 2500 lbs = 1.01
Vehicle weight 2501 to 3500 lbs = 1.00
Vehicle weight > 3500 lbs = 0.99

Still, no matter what you do, it will never be fair for everyone.

3. If having fun at the club is of the highest priority (as much as I don't want to say it) just eliminate any form of valuable prize for championship points (just wait until '09 to do it ). This way, I think less people will complain or try to use the system in their favor if a weakness is found in the system. Maybe instead of giving free passes to championship winners, you give CDC members a free pass after attending so many events. Spread the wealth over the masses who keep the club flourishing vs. the few who want to fight over a championship.

4. Ban FredK for being FredK.

[Wade Chamberlain]

4. Ban FredK for being FredK.

Finally, the voice of reason.


I can attest that the 1.03 R-comp multiplier isn't enough. I ran street tires for the last event just for grins. The 1.00 vs 1.03 tire multiplier wasn't nearly enough to get my indexed time up where it normally is w/ R-comps.

[AJ_RDR_Civic]

You missed Fred's humor... FTD means Fastest Time of the Day.
SCCA has street tire classes. The meaning of street tires is a problem. The fastest street tires are better than 2nd rate R compounds. I run Toyo R-888 (R-comps) as my daily driving tires and Hoosier A6s for autocross on my M-B 190E so R-888s really are street tires in my case.
As it stands the current index is dominated by highly modified cars and if the index isn't changed no car legal for SCCA stock has a chance. I've been driving a stock legal Boxster and don't usually lose to genuinely stock cars. If I felt the need I could lighten the car from 3100+ lbs to 2500 lbs, install full race suspension, carbon fiber body panels with flares to fit 345 width R-Comps and limited slip differential without changing my CDC index...
SCCA's index isn't perfect but it's more fair to non-racecars.

Ted

SCCA does have Street Tire class's, but their definition of a street tire is anything with a UTQG rating of 140 or higher. currently there are only a couple tires that are labeled 140, the Bridgestone Potenza RE-01R(some are 140, some are 180, depends on the tire size) and the Toyo R1R(140). currently the 2 best tires to run in the Street classes in SCCA are the RE-01R's and the Dunlop Direzza Z1 Star Specs(have a 200 UTQG).

[mla163]

I am in favor of the current system. It's easy, it's simple. I like the fact that I compete against a variety of cars in the 1.01 class. I like that little mods don't bump me into a class that I don't want to be in. I have heard no gripes other than that people are not putting down the correct modifiers when they sign up (accidentally,of course).

A few comments (not complaints): I think it may need a few statistical tweaks, i.e. somebody smarter than me compares data between cars in different classes and normalizes the values. Should R-comps be 1.03 or 1.035? etc. We may have to add another digit to the modifiers. Also, we may want to add a few more classes for weight and horsepower. There is a pretty big difference between 150 hp and 250 hp, 2500 lbs and 3500 lbs, but these are all in the same class. Maybe we divide these up. As Ted mentioned, there are no restrictions on suspension and drivetrain. However, these are hard to quantify into a definable class. I don't see any easy way to define a suspension class or enforce it. Unless you go with "stock" and "modified".

After dealing with the SCCA index this year, I am not a fan of their classing system. It favors certain cars in certain classes with certain mods. It eliminates the freedom of being able the modify a car to ones tastes. My car is not set up for STU, and can never be set up for STU, so I am out of contention before the first race.

A few suggestions:

1. Take a look at the results and tweak the modifier numbers to normalize the values, if needed.
and/or
2. Add or adjust classes for weight or power to normalize values.
3. Maybe add a "stock" class. Modifiers only for power and weight. Street tires only. No mods other than simple things. This class can be evaluated separate, like the small bore class with rankings and trophies unique to this class.
4. If Ed is concerned about encouraging new drivers (which I agree with). Perhaps we add a class for first year drivers or younger guys. Again, this can be separate from the rest of the group.

[ButtDyno]

First some observations about what's been posted so far:

1. Some liked the old 2007 indexing better because it gave the newer drivers more of a feeling of accomplishment as they improved.

It also gave experienced drivers a feeling of accomplishment as they sandbagged

2. Some are surprised that it appears that some participants are not truthful when entering their indexes in the system. (I've noticed that this year, several people have started nit-picking what people have on their cars. I'm not sure this environment is very heathly for a club trying to focus on "fun").

I can think of two examples. One, a guy was running Hoosiers and listed himself as street tires. Pretty flagrant, IMHO. Two, a person whose hat says they have 200 more horsepower at the wheels than they're registered for. Can't really explain that one.

(I personally think that we would then get into debates on what tires should be considered street tires, like the Bridgestone street tires that are as sticky as V710 (and cost as much).)

The fastest street tires are better than 2nd rate R compounds.

The RE01R's, while very sticky for a street tire, are not in the same league as an RA-1, V700, etc, let alone a true DOT slick like the V710 or A6. We've even seen this with same day same car testing when the Morans go from RE070s (one of the stickiest street tires out there) to their RA1's. If they were really as sticky as V710's, people wouldn't run V710's in stock classes. Yeah, street tires are more expensive than they used to be, but they're easier to drive to the event on, and they do last longer as long as you're not shaving them. And they are still much cheaper than V710's and A6's.

As for cost:
Hoosier A6's for my WRX in 245-40-17 are $244 each. If you're lucky you'll get 70 or so good runs out of them. There might be tread left but they're probably heat cycled to death at that point.
Dunlop Direzza Z1's in the same size are $148 each. RE01R's are $212 each. And the Dunlops are better tires. Even if you had them shaved, they'd still be much cheaper and last longer.
(all prices from tirerack)

From a purely practical perspective, you can't regulate this away. No matter where you set the bar, someone can buy a tire that barely clears that bar, and shave it, if they are so inclined.

I think the penalty for tons of HP is to much, on the small CDC courses no one can use that much power, anything over 250 RWHP should have the same index.

Yeah, it's not like anyone sees their peak horsepower on a short course. How about we go by how much torque you have at 2500 RPM instead Time to buy that S2000 I want!



Now, generally... I am largely indifferent either way as I just end up calculating out the PAX

But I agree that the R-comp multiplier needs to go up a little bit. You hardly ever see anyone on street tires in the top 5 (has it *ever* happened?) or the top 10 in the index. At local SCCA events, the PAX often works out the other way, even with the same drivers that run CDC events. (Except Brian, damn you)

The biggest loophole that I see is not penalizing suspension mods, like Ted and Mark say. Here's my proposal: a handicap of 1.01 if you have anything other than OEM springs. That's an easy test, and going to stiffer springs is really what buys you the most for autocross suspension wise. If 1.01 is too steep, maybe 1.005.

Just an idea

John
#199

[Tedzilla]

"SCCA does have Street Tire class's, but their definition of a street tire is anything with a UTQG rating of 140 or higher. currently there are only a couple tires that are labeled 140, the Bridgestone Potenza RE-01R(some are 140, some are 180, depends on the tire size) and the Toyo R1R(140). currently the 2 best tires to run in the Street classes in SCCA are the RE-01R's and the Dunlop Direzza Z1 Star Specs(have a 200 UTQG)."[/quote]

UTQG is determined by each tire maker and is not standardized. A Toyo R-888 is softer and stickier than a Toyo RA-1, both have a 100 UTQG. A shaved Bridgestone RE-01R (200 UTQG) is stickier than a Kumho VictoRacer V700 (60 UTQG). Use a Durometer, use your fingernails, better yet drive them back to back. The best 'Street Class' tires aren't really very good for street (read their cold weather warnings). Most serious drivers shave them, put them on special wheels and don't use them except to autocross. You'd be better off with R-Comps if you're going to go though all that trouble.

Ted

[ButtDyno]

UTQG is determined by each tire maker and is not standardized.

That's not entirely true.
http://www.tirerack.com/tires/tiretech/ ... ?techid=48

Re: standardization:

UTQG Treadwear Grades are based on actual road use in which the test tire is run in a vehicle convoy along with standardized Course Monitoring Tires. The vehicle repeatedly runs a prescribed 400-mile test loop in West Texas for a total of 7,200 miles. The vehicle can have its alignment set, air pressure checked and tires rotated every 800 miles. The test tire's and the Monitoring Tire's wear are measured during and at the conclusion of the test. The tire manufacturers then assign a Treadwear Grade based on the observed wear rates. The Course Monitoring Tire is assigned a grade and the test tire receives a grade indicating its relative treadwear. A grade of 100 would indicate that the tire tread would last as long as the test tire, 200 would indicate the tread would last twice as long, 300 would indicate three times as long, etc.

Further, the manufacturer can get fined if they are out of whack:

When looking at UTQG ratings it is important to realize that the Department of Transportation does not conduct the tests. The grades are assigned by the tire manufacturers based on their test results or those conducted by an independent testing company they have hired. The NHTSA has the right to inspect the tire manufacturer's data and can fine them if inconsistencies are found.

The test only mandates 7200 miles though, which is where the variance comes in:

The problem with UTQG Treadwear Grades is that they are open to some interpretation on the part of the tire manufacturer because they are assigned after the tire has only experienced a little treadwear as it runs the 7,200 miles. This means that the tire manufacturers need to extrapolate their raw wear data when they are assigning Treadwear Grades, and that their grades can to some extent reflect how conservative or optimistic their marketing department is. Typically, comparing the Treadwear Grades of tire lines within a single brand is somewhat helpful, while attempting to compare the grades between different brands is not as helpful.

A Toyo R-888 is softer and stickier than a Toyo RA-1, both have a 100 UTQG. A shaved Bridgestone RE-01R (200 UTQG) is stickier than a Kumho VictoRacer V700 (60 UTQG). Use a Durometer, use your fingernails, better yet drive them back to back.

If you want to lend me a set of V700's, I'd be happy to... I've got some 140-treadwear RE01R's on the car right now (235-40-17). I haven't found any quasi objective skidpad data yet. There's more to a tire being fast than durometer readings though, or else the R1R would be a lot more popular. From what I have read, it is a stickier compound than the RE01R/Dunlop/etc but you don't see many people using them on bigger cars because they apparently don't work very well in those conditions (soft sidewalls, or whatever).

Also the UTQG test presumably uses unshaved tires, while Kumho recommends shaving the Victoracers, so that's another reason this is not a great comparison. They're also really old and tire technology is constantly advancing, letting us get both more stickiness and more treadwear. Comparing the R888 to the RE01R is a better comparison IMHO as they are both relatively recent tires with similarish treadwear ratings, and no one would say that the RE01R was faster, even shaved.

Most serious drivers shave them, put them on special wheels and don't use them except to autocross. You'd be better off with R-Comps if you're going to go though all that trouble.

I like my special wheels

[kyle.bowker]

Treadware grades (AA, A, B, C) are determined by UTQG and are virtually worthless to the auto-x enthusiast. Treadware ratings (400, 200, 100, 60), on the other hand, are determined by the tire manufacturer themselves and only provide a relative treadware rate comparison among different model tires made by that manufacturer (i.e. Toyo RA1 vs. Toyo R888). They cannot be used to compare tires among different tire manufacturers (i.e. Kumho Victoracer vs. Hoosier A6).

[Tedzilla]

ButtDyno,

I found your unofficial CDC pax very good... and it would be useful to this discussion.
Tires aren't the problem with the CDC index. In order to be competitive at the highest level in this club I would have to spend around $14K, ruin the resale value of my car and not be legal or competitive in any other series or build a car with no purpose other than to run CDC for as long as we use the current index which may not be long. Thanks, but no thanks. I'd rather settle for 5th in the Driver's Points and drive the only stock legal street car in the top 10.
I'm not willing to do what it takes to win under this index and I can live with it. However I do get tired of listening to folks who show up at a competitive event in their mother's Camry on snow tires whining and moaning about it not being fair that fast cars with fast drivers always win... that's racing, we're casual and friendly, but it's racing.

Ted

[wrathe74]

4. If Ed is concerned about encouraging new drivers (which I agree with). Perhaps we add a class for first year drivers or younger guys. Again, this can be separate from the rest of the group.

Aug 30th was my first ever autocross, I ran completely stock suspension, no camber/toe adjusts, and with my daily all-seasons!

I had been looking forward to this all-season, I had quite a bit of fun, and was nervous - not about driving, but about remembering the course; however I do think this course was easier to remember than the Frederick courses.

As for comparing myself to others in my index (1.01) I feel like I have a long way to go...and at the very least I definately need better tires if I'm going to even compare. I'm not saying I'm dis-heartnened; in my case its a goal, challenge even, to become better; knowing that my index shows I should be able to get 20+ seconds faster ...

Bottom line, as a firs-timer I was here to have fun, and drive like I've wanted to do for so long with my car...I think I accomplished that - Thank You CDC!
IMO, though, until I start modifying the suspension/brakes/tires... I feel there is no point in comparing myself to others in my index because there is such a wide range. It would have been nice to see how I compared to others who are new, even if we aren't in the same index because it would let me know how I'm performing for my own benefit - not to win an award or anything.

Not to single out new/young drivers, but maybe make it so we don't even have an index until after we have X amount of races; this way its about improvement in driving and focus more on times and how well you compared from your worst to best times for that race. If everyone in the "New Driver Series" class shows a 5sec lap time improvement, thats more beneficial.

[smetzger]

Any index system that doesn't take into account suspension will favor the more highly modified cars. But I don't see how to do this without using SCCA or NASA.

Does anyone know if GeorgeCo.org in the purple mini is GS? He seems to be a decent driver and if he is GS then his car should be competitive. Yet in the last showing he came up 25th in raw times, yet dropped to 34th in indexed times. To me that either shows he is not as good a driver as a lot of people, or the index system isn't working.

I think tweaking the numbers and adding more HP and weight categories would probably be the best and maybe FWD, RWD/AWD.
Or we go with SCCA with Novice and TIRE added in.

Other things to consider, maybe adding some more 'classes' like how small bore works. If we want to encourage new drivers then a Novice class would be good. Whatever index system is used just break out the Novices into a separate group and run them together. Once you 'win' one race or you run 8 Auto-X's you are no longer eligible for Novice. Also, a PRO class maybe for those who are looking to step up.

The way membership and signing up for events works, I think it hinders Novice's. That's Ok by me. But we should step back and try to decide what the goal of CDC is. Is it a friendly environment for doing Auto-X on Sats? Or is it a friendly place to introduce people and foster them in the sport?
The two aren't mutually exclusive, but if we are going for the 2nd goal then more changes other than the index are needed.

Thanks,
Scott

[TubeDriver]

Here we go again. One goal we probably should try to reach is to NOT have a new index system every season.


The current system , while a staggering step forward over the original index system IMHO, has many faults. If we started an analysis of every CDC competitors car, tried to take into account all the various modifications and all the possible combinations we would probably end up with something VERY similar to the SCCA PAX index. I have competed in various clubs using different Index systems but the SCCA system is the most comprehensive.

The modified SCCA stock class index I proposed last year would have eliminated much of the complaints we hear about the current system. Specifically, our current system with a "hp at the wheels" requirement simply CAN NOT be enforced so I can't imagine why anyone would be surprised if someone played a bit loose with the rules. My modified SCCA stock class indx system would have no problem in this area. It also would have eliminated sandbagging which was one of the big criticisms of the original CDC index system.

[ProDarwin]

1. Some liked the old 2007 indexing better because it gave the newer drivers more of a feeling of accomplishment as they improved.

First of all, any driver who actually experienced both of the index systems is certainly not a "newer" driver. Second, I believe the index system was put in place to provide more than a false sense of accomplishment. The goal (for most) was to eliminate the car from the equation, and focus on who is the better driver.

2. Some are surprised that it appears that some participants are not truthful when entering their indexes in the system. (I've noticed that this year, several people have started nit-picking what people have on their cars. I'm not sure this environment is very healthy for a club trying to focus on "fun").

Yes, there have been cases of some participants not being truthful. Some of it is mistake - I was once listed as driving a stock 02 MR2, when I was really driving John's 93 MR2 on R comps. The difference under the current index system placed me much higher than I should have been. I sent an email to correct the error. Some of it is lying competitors. With an index system based on numbers that cannot be verified, there is bound to be some speculation, especially when the error appears to be on the order of several hundred horsepower.

3. Some liked the Small Bore Series Concept and thought is the most fair. However, if the concept is trying to have a low cost class that most can afford, why allow r-compounds? If only we only allow street tires, the cost would be even more affordable. (I personally think that we would then get into debates on what tires should be considered street tires, like the Bridgestone street tires that are as sticky as V710 (and cost as much).

I liked the Small Bore Series, but if the concept is to have a low cost class that most can afford, it seems to be self defeating. Most CDC participants are autocrossing a car that is their daily driver, which is relatively cost effective. Purchasing a <1800cc car to compete in that series is not exactly low cost. On the subject of R compounds... the series started as a "vintage" series. Most street tire sizes have vanished for these cars. "ST" level tires are no longer available in any sizes below 15". Since many of these cars are running 13-14" wheels, I'd say its only fair to allow R comps.

The Bridgestone street tires (not sure if you are referring to the RE01R or RE070) are nowhere near as sticky as street tires.

The best 'Street Class' tires aren't really very good for street (read their cold weather warnings). Most serious drivers shave them, put them on special wheels and don't use them except to autocross. You'd be better off with R-Comps if you're going to go though all that trouble.

Out of all the ST* competitors at SCCA events, I only know of one that switches tires at each event. I and several others give him endless crap about this. I agree that serious drivers do this... at tour events/national level competition. But at local events it isn't incredibly common.

I agree that the 2008 system is leaps and bounds ahead of the 2007 abomination. I also believe that the current system could be refined to come up with a more fair system. Ted's (or anyone else's) SCCA stock class based system would probably work as well. Keep in mind that the majority of the competitive drivers at CDC events also campaign their cars at various other autox events as well, most of which operate using SCCA rules. Having a system that requires you to build your car in a completely different manner in order to win is not very enticing.

[TubeDriver]

Ted's modified SCCA Index system? I thought I was the one who created, posted and argued for the "Modidfied stock class SCCA system?

Anyway, it does not matter, there is too much anti-SCCA sentiment at CDC to ever see my proposed Index system implemented. But in the future, if CDC changes the index system again it should probably leave out non-enforceable variables like "RWHP".

I agree that the 2008 system is leaps and bounds ahead of the 2007 abomination. I also believe that the current system could be refined to come up with a more fair system. Ted's (or anyone else's) SCCA stock class based system would probably work as well. Keep in mind that the majority of the competitive drivers at CDC events also campaign their cars at various other autox events as well, most of which operate using SCCA rules. Having a system that requires you to build your car in a completely different manner in order to win is not very enticing.

[Jim Harris]

The current system actually works pretty well.

That said, the suggestions by Fred, Brian, and others about the horsepower index and the R-comp index are pretty reasonable. The comment about using horspower at the crank as advertized instead of at the wheel is also reasonable; using horsepower at the wheels just invites too many mistakes of judgment.

I don't have any problem with allowing for suspension mods, too, except that it makes the construction of the total index more complicated. Not so complciated we couldn't live with it, admittedly.

I see my competitiveness slipping away....

Jim
Mustang Bullitt

[ProDarwin]

Ted's modified SCCA Index system? I thought I was the one who created, posted and argued for the "Modidfied stock class SCCA system?

My mistake, brain fart as I was typing that. I saw the green text in your name but from some reason saw "tedzilla".

[TubeDriver]

You can't use "advertised hp at the crank" because that becomes meaningless as soon as someone drops a turbo into their engine bay or adds engine/boost management to an OEM FI setup. You have to start taking account what mods are on a vehicle.

The current system actually works pretty well.

That said, the suggestions by Fred, Brian, and others about the horsepower index and the R-comp index are pretty reasonable. The comment about using horspower at the crank as advertized instead of at the wheel is also reasonable; using horsepower at the wheels just invites too many mistakes of judgment.

I don't have any problem with allowing for suspension mods, too, except that it makes the construction of the total index more complicated. Not so complciated we couldn't live with it, admittedly.

I see my competitiveness slipping away....

Jim
Mustang Bullitt

[wrathe74]

You can't use "advertised hp at the crank" because that becomes meaningless as soon as someone drops a turbo into their engine bay or adds engine/boost management to an OEM FI setup. You have to start taking account what mods are on a vehicle.

Dyno-day maybe?? wonder if its possible to rent one - like the setup they do in Carlisle, PA?

[TubeDriver]

That is completely unmanageable. We can barely get 10 organizers to show up for a dinner meeting much less 250+ CDC autox competitors to show up for a "dyno day"


Plus, requiring a dyno to autoX completely defeats the idea. No autoX club that exists requires a car to be dynoed.

You can't use "advertised hp at the crank" because that becomes meaningless as soon as someone drops a turbo into their engine bay or adds engine/boost management to an OEM FI setup. You have to start taking account what mods are on a vehicle.

Dyno-day maybe?? wonder if its possible to rent one - like the setup they do in Carlisle, PA?

[TubeDriver]

just for giggles, here is my original modified SCCA Index system proposal cut from earlier threads:




"For those of you not familiar with the SCCA PAX system, the SCCA looks at the actual results of over 200 events every year. Stock cars are placed in classes depending on how well they do. The stock classes range form SS to HS (fastest to slowest). So SS class cars are Z06 Corvette, Lotus Exige, Porsche Turbo and GT3. The next class is AS and is primarily made up of S2000, Boxster S, C4 Corvettes. This continues all the way down to HS cars (Chevy Baretta, Fiat 124 Sedan, Scion TC etc.) Virtually ALL car models are covered and fall into one of the stock classes, look it up and I bet you can find your car listed.

The idea behind that SCCA PAX is to answer the question: who is a faster driver and how to compare times when one driver shows up in a Z06 Corvette and another driver shows up in a Scion TC? We know that if the two drivers are fairly close in terms of skill, the Z06 driver will get a faster raw time then the Scion TC driver. But since each class gets its own handicap, we can compare the two runs. The Z06 driver get a 60 second run and has a PAX index of .848 so the Index time for his run is 50.88. The driver in the Scion TC gets a 64 second raw time, her index is .789 so her Index time is 50.496. In this case, the Scion driver would be in 1st place and the Z06 driver is in 2nd place. The VAST performance difference between the two vehicles (Scion TC and Z06 Corvette) has been equalized and the better/faster driver gets recognized.

The issue that many people have with the SCCA index is how it handles r-comps and mods. I would suggest using the stock class Index as a starting point and then assigning some additional handicap for mods. Something simple might be to say that basic bolt ons (intake/exhaust/springs/shocks/swaybars/wheels/seats/steering wheels/mild internal engine mods like cams) puts you in a “modified” class which would be your stock class index + some additional mod index modifier. We could also make a “ultimate” class for cars with engine swaps/forced induction/engine management on forced induction cars which would put you into a “ultimate” class made up of your stock index + a “ultimate” modifier.

Lastly, we could average all the street tire raw times and all the r-comp raw times at the end of each event to get an r-comp Index modifier number. This number would handicap all cars that ran on r-comps. So my PAX modifier from the last event would be stock class (.838 since I have a S2000) + “modified class modifier (due to front swaybar and exhaust) + r-comp modifier = my index modifier for that event.

We could certainly handle mods and r-comps differently; there are a lot of ways to take into account these variables. Using the SCCA stock class as a base gives our index some basis in reality.

Also from a follow-up post of mine;



My system only has the stock classes (SS to HS). Period. No prepared classes, no street prepared, etc.


Then each stock class Index gets a modifier based on level of mod (if any) and a modifier for r-comps. My suggestion was to use two levels of modification 1) bolt-ons and 2) ultimate (engine swaps, forced induction, and engine managment for forced induction cars (which can easily add 20-50hp).


How simple is this?


let's looks at a few concrete examples.


My S2000 currently has a front swaybar and a catback exhaust. My index would be AS (.838) + bolt-on mod addition (.xxx) and also a r-comp modifier (.xxx). My total index is a single score based on the variables above.

Your mustang would start with a FS Index (.809). you would add a bolt-on mod addition (.xxx) due to your springs/wheels/camber plates/exhaust/pulleys etc and a r-comp addition at .xxx (if you decide to run on r-comps).

My Miata would start with CS Index (.822) and then get a bolt-on Index addition (.xxx) due to coilovers/wheels/exhaust and a r-comp addition (.xxx)


Most people would fall in stock or bolt-on mods classes. Basically, a stock car means just that, a completely stock car (I would probably not require OEM tires, any NON r-comp tire is fine as long as it is on OEM size, offset wheels). Basically, any mod and you get a bolt-on modifier
(yes, that means cars with a tons of bolt-ons will gain some advantage over cars with only an exhaust). Any car with an r-comp (wear rating less than 140) will get r-comp modifier.

The SCCA stock classes have some validity based on the standing at hundreds of events each year. Is it perfect, no but probably a lot more valdid then just breaking cars in 3 groups and having at it."

[wrathe74]

Didn't mean that as a Requirement...i was thinking more along the lines, setup a dyno/track day and whover wants a dyno pays for a few pulls.
but regardless, i get the point, dumb idea

That is completely unmanageable. We can barely get 10 organizers to show up for a dinner meeting much less 250+ CDC autox competitors to show up for a "dyno day"


Plus, requiring a dyno to autoX completely defeats the idea. No autoX club that exists requires a car to be dynoed.