It's about time this forum had a thread for common questions and answers. Feel free to add specific information or links on autocross or autocrossing VWs..
What is autocross?
Autocross, at its essence, is very simple. It's motorsports for the masses. Anyone can come out, with virtually any car, and test their driving skills in a safe, controlled manner. My favorite description of what exactly it is comes from Dennis Grant, one of the founders of the Street Modified class: "The basic concept is simple: take a large paved area. Describe, on it's surface, a race course, marked off with traffic cones and flour lines. Place a timer at the start and finish, and one car at a time, drive through as fast as you possibly can. Hit a cone, and get two seconds added to your time. The track is never the same twice from event to event. There are no practice runs. We run rain or shine. In Formula One terms, an autocross is like bringing your team to a track (which was completely torn down and rebuilt from the last time you were here); you get three qualifying laps, from standing starts (each one!) and on cold tires (no tire warmers allowed). The next day, you do the same thing, but in the opposite direction, and then the track owner rips up the track and starts building a new one. 6 runs total [generally 3 runs for one day events], best one each day counts. This all makes for a sport that is very different from any other style of motorsport. On the whole, it is less expensive and less dangerous than other forms, as there is very little chance of crashing into something hard, and speeds tend to be slower. On the other hand, it demands a very high level of aggressiveness and driver precision - you have to be instantly fast, and everything must go right right away. There is just no margin for error.
Races are won and lost by thousandths of a second, and the mental pressure can be enormous."
Is it dangerous?
Just like any other form of motorsports, Solo2 has some element of risk. However, the SCCA has specific rules defined to make an event as safe as possible and, in general, Solo2 is at least as safe as driving on the street. Usually, there are no more than 3 cars on a course at a given time, and that's only when the course allows sufficient separation. Workers are positioned around the course with fire extinguishers and red flags to inform cars when there's a problem. Courses are designed so that if a car does lose control, or spin, there's nothing even close to it that could be hit. Spectators are only allowed in certain areas around a course. Kids under 12 are not allowed in hot areas, which include grid, prestart, course and impound. Be aware that other organizations have differing rules, and many are not as safe as an SCCA event.
What is ProSolo?
ProSolo is a national series run by the SCCA. Where most Solo2 events run one car at a time, a ProSolo runs two cars head-to-head on mirror image courses with a drag strip start and a Christmas tree. Reaction times are part of the times. Each car gets 4 runs on each side and the best run on each side is totaled for their time. ProSolo also has a Super Challenge at the end of each event. Each car in the Challenge has a dial-in similar to bracket drag racing. In a given round, the two cars get a run on each side, whoever wins advances.
Example map: http://www.wincom.net/trog/new...e.JPG
Don't expect much in the beginning..
Out on the street, we all think we're the best drivers. And who wouldn't? There's no evidence to the contrary, so we get to think whatever we want. Often someone new checks out an autocross and just thinks it doesn't look like that big of a deal. Driving is a lot different than watching. Once you get to the start line, and there's a big sea of cones in front of you, things change. For those of you who may be nervous or a bit intimidated already (hopefully you're not!) the next couple sentences are not for you. For the street racer or canyon cruiser or spirited street driver, read on. Here's the first step. Check your ego in at the gate. Assume you can't drive, because chances are, compared to a seasoned autocrosser, you can't. This isn't a hit or a knock on your driving skills, because we all start out at this point. We all think we're the greatest, and then we get out there on course, see our times, and realize we're not. The best things you can do is listen to the experienced people around you, pay attention during the course walk, and take advice. Your goals for a first autocross should be to stay on course and, if you can do that, improve your time by the end of the day. At this point, the car you drive, or what modifications it has won't really matter. In fact, having a modified car will only hurt as it may mask things you may be doing slowly. The primary limiting factor will be the driver. As you get better, you will be able to truly take advantage of making the car better. A couple of mantras you will probably hear repeated in one form or another, but won't really "get" for awhile. "Slow down to go faster." The beginner usually tries to be too fast in the slow parts of a course, and too slow in the fast stuff. "In like a lamb, out like a lion." Generally, late apexing is the only answer.
Walking the course
Your goal when walking the course is twofold. To commit the entire course to memory so you can go through it in your head at "full speed", and to choose the line through the course that you think will be the fastest and be able to do it without thinking. So walk the course twice. Generally try to focus on what you're doing and have enough clear area ahead of you so that you can see what the course will look like when you drive it. Break the course up into sections and try to analyze the entire section as a whole to determine where you want the car to be at each turn. Memorize it, play it back through your head, and go!
SCCA Solo2 Classing Structure
Cars are classed in the SCCA first by modifications and second by the cars' set of traits and capabilities. Each ruleset is strict; in other words, if it doesn't say that you CAN do it, than you CAN NOT do it and remain legal for the class. The general progression of levels of modifications is as follows: Stock, Street Touring, Street Prepared, Street Modified, Prepared, Modified. Note that this is not a linear progression. Everything, for instance, that is legal for Street Prepared is not necessarily legal for Prepared. Once a car is placed in one of these categories, its placed in a specific class along with other cars that perform similarly. Example cars for each class are below.
Why the rules are the way they are; or why even adding 1psi of boost must be considered the same as adding 20 psi.
The ruleset is very stringent. To people new to autocross or motorsports in general this may seem antithetical. "Why does having a chip place me in Street Modified, its only a software map and I'm still underpowered!" or "I have a different transmission in my car, but it doesn't really help that much, so why am I placed in such a hard class?" are common questions. The ruleset for each class has to cover all cars. Further, the rules must be able to place cars properly based on the car's potential as it would be if it were modified TO THE LIMIT OF THE RULES. This is important. Changes in stock boost level, for example, are illegal in Stock, Street Touring, and Street Prepared. It would be an impossible task to set boost level maximums and actually be able to control or check levels at an event. The alternative is either allowing unlimited boost (which is what Street Modified does) or allowing no boost changes (SP and lower). Note that the below listings are not exhaustive. For complete rule details see the SCCA Rulebook. This is just a general guide.
Roll bar or roll cage (SCCA specs)
Shock absorbers with the same mounting type
Wheels with the same diameter and width as stock (i.e. a GTI 337/20th must use a 18x7.5", it cannot use a 17" from a GTI)
Air filter (not intake)
Tires (anything D.O.T. legal including R compounds)
Classes and example/common cars for each class
Super Stock: Corvette Z06, Viper, 996 911, 93+ RX-7
A Stock: C4 Corvette, Mitsubishi Evolution, Subaru WRX STi, 00-04 Honda S2000, E46 BMW M3, Porsche Boxster S
B Stock: Mazda RX-8, Nissan 350Z, E36 BMW M3, MR2 Turbo, Porsche 968 M030
C Stock: Mazda Miata 1.8L, Toyota MR2 Spyder, Porsche 914
D Stock: Integra Type-R, Audi S4, VW GTI/Jetta 24v VR6, R32, Lexus IS300, BMW 325/328/330
E Stock: Toyota MR2 non-turbo, 90-97 Mazda Miata, Porsche 924
F Stock: Camaro V8, Mustang V8
G Stock: Celica GT, Mini Cooper S, VW Corrado VR6, GTI/Golf/Jetta 1.8T, 16v
H Stock: Mini Cooper, BMW 318
STS - four seat vehicles, maximum displacement of 3.1L NA and small displacement forced induction sedans
Shocks, springs, swaybars, strut bars/braces
Wheels up to 7.5" width
Tires up to 225 width
Street tires with at least 140 treadwear rating
Short shift kits
Fully upholstered seats
Body kits, spoilers, wings, removal of factory trim
Brake pads, rotors, lines
Intake, cat back exhaust, header
Emissions legal engine management
Relocation of battery
STX - 2WD vehicles may use any LSD, engines up to 5.1L NA, 2.0L forced induction.
STS modifications carry over
Any LSD for 2WD vehicles
Wheels up to 8" width
Tires up to 245 width
STS: Honda Civic, Dodge Neon, Toyota Celica, Mini Cooper, VW GTI/Golf/Jetta 1.8T, Jetta/GTI 16v, Corrado VR6, Audi A4 non-Quattro
STX: Honda Civic, Mini Cooper S, Subaru WRX, Integra Type R, E30 BMW M3
The allowed modifications in SP are extensive, the following is a general summary.
Anything allowed in Stock
Update/Backdate rules for any cars on the same line in the rulebook
Any wheel and tire width
Shocks, springs, swaybars, strut bars/braces
Any fully padded seats, steering wheels, pedals, roll cages up to 8 points of attachment
Fuel cells allowed with certain qualifications
Limited Slip Differentials
Carburetion, fuel injection, intake manifolds, intake, exhaust manifolds, exhaust
Overbore to .0472" with oversize pistons
Port matching, milling
Classes and example/popular cars for each class:
ASP: C5 Corvette, Lotus Elan, 996 911, 93+ RX-7
BSP: C4 Corvette, E36 BMW M3
CSP: Honda CRX, Toyota MR2 Spyder, Mazda Miata, Mazda RX-3
DSP: E36 BMW 325/323/328, Lexus IS300, E46 BMW 330, Fiat X1/9, Acura Integra GS-R, Mini Cooper S
ESP: Camaro V8, Mustang V8, WRX, WRX STi, Mitsubishi Evo
FSP: Honda Civic 92+, VW Scirocco 8v, VW Rabbit/Jetta 75-84
Anything in Stock, Street Touring, or Street Prepared
Drivetrain is unlimited except: engine from same company as manufacturer (Honda/Acura, VW/Audi swaps are OK)
FI: 3L OHC, 4L pushrod
Suspension is unlimited except: Must use original suspension attachment points
Rear passenger seat can be removed
Hood/front fenders can be changed
Firewall, roof, doors, rear quarter panels, floor pans, trunk lid must be stock
FWD: 1800 lbs NA, 1900 lbs FI
RWD: 2200 lbs NA, 2400 lbs FI
AWD: 2400 lbs NA, 2600 lbs FI
FWD: 1500 lbs NA, 1600 lbs FI
RWD: 1900 lbs NA, 2100 lbs FI
AWD: 2100 lbs NA, 2300 lbs FI
SM: Any sedan/coupe with four seats (not sports-car based) such as VW Scirocco, Golf, Jetta, Passat, Dodge Neon, Honda Civic, BMW 3 series (including M3), Supra, WRX, Mitsubishi Evo, Talon/Eclipse, etc, etc
SM2: All two seaters/sports cars such as Corvettes, MR2, 911, Z cars, Honda CRX, Miata, or an underweight or over displacement SM car. All Lotus are excluded.
Autocross specific wheel philosophy
The general, most common rule of thumb in autocross is get the most rubber possible down at all 4 corners. While there are some minor exceptions to this rule, it almost always holds true. Wheel size will help you do this. Lets start with diameter. On the street, we all run big wheels because it looks cool. Drag racers tends to run small, wide wheels and tires with lots of sidewall. Several factors play into choosing a wheel diameter: weight, gearing, and fitment. The smaller the wheel, obviously, the lighter it is. The less unsprung mass, the better, so this is a good thing, and favors a smaller diameter. The shorter the wheel/tire combo, the shorter your gearing will be as well. So if you have a low-powered car, or your gearing is already very tall, a smaller diameter wheel will help you get a better gear ratio. Suddenly, you might not have to be shifting to third in a short straight. On the flipside, if you have a car with very short gearing (the STi comes to mind), a taller wheel/tire combo could help you stretch that out. The last main factor is fitment and tire size. Make sure you have an appropriate tire size for that wheel, and make sure it will fit on your car, clear your brakes, and not cause any tremendous problems.
As two examples, there are the high powered ASP/BSP cars, and there are the low powered ASP/CSP/FSP cars. The Corvette's of ASP/BSP want as much rubber as possible under their high powered, relatively heavy cars. So they run 17x11s or 17x12s with 315 or 335 width tires. The ASP Corvettes may also run 18s up front, allowing even less sidewall for better turn-in. The BMW M3s of BSP and even the E36 DSP cars are moving to 18s with 285 series tires and very short sidewalls. The low-powered, smaller, more nimble cars of ASP/CSP/FSP have none of these weight or power problems. So they all run 13" wheels that give them the shortest gearing, and the least amount of weight. Chances are they couldn't heat up a 275+ width tire anyway, so the 225/235 R comounds that Hoosier and Kumho offer are just fine.
Now on to wheel width. Let's say we've decided we're going to run 13" wheels on our SP cars. We have tires available that give us an 8-9" recommended width. What do we do? Well, the common thing to do here is to move to the wider side of the spectrum. The more width the wheel has that the same tire is on, the more width of the tire will be put down, so the wider the contact patch, to a point.
Of course, in a stock class, your wheel choice is limited to what came with the car, in which case you simply go with the lightest thing you can find, and then stuff the widest tire you can on it. C Stock Miata's usually have 225s on their 5.5" wide wheels.
Add more good information!
Modified by Mhyrr at 6:30 PM 1-28-2005