Autocross is a form of motorsports that emphasizes safe competition and active participation. An autocross is a timed competition where drivers navigate one at a time through a defined course on either sealed or unsealed surfaces. Autocross differs from road racing or oval racing in that generally there is only one car on the track racing against the clock rather than other cars. As an entry level motorsport it provides a stepping stone for drivers looking to move into other more competitive and possibly expensive forms of motorsport including, on-track driving (DE’s), rallies and Club Racing.
ARPCA – Beginners Guide to Autocross by Frank & Kristi Gaus (National AX Champions and ARPCA Members)
Autocross Events:
Autocross courses are typically around a 1/2 mile in length and tend to place more emphasis on car handling and driver skill rather than on sheer horsepower. Autocross courses are set up using soft orange traffic pylons which will not damage your car, but they do melt! Events are run at speeds usually between 40-65 MPH, usually in 2nd gear. Autocross is a “performance driving event” and a safe way to learn how to drive your car at its limit. You not only learn how to handle your car at speeds that you drive daily, but you also:

Autocross
- Gain confidence in your driving ability
- Learn the limits of your car’s brakes
- Learn correct seating, hand, and feet positions
- Learn the limits of your car’s tire adhesion
Finally, Autocross is a social gathering of new and old friends and LOTS OF FUN!
Events typically have many classes which allow almost any vehicle, from economy sedans to purpose-built vehicles, to compete. Due to the nature of a typical track speeds can be slower in absolute terms when compared to other forms of motorsports, usually not exceeding highway speeds, but the activity level (measured in discrete turns per minute) can be higher than even Formula One due to the large number of elements packed into each course.
ARPCA follows PCA Parade Autocross Rules. We use the “Medium” region car classification system.
APRCA Car Categories
There are four categories of classes for Porsches – Showroom Stock, Production, Improved and Modified. Categories are related to automobile configuration. There is a separate category for all non-Porsche vehicles.
- Showroom Stock (S) category contains classes of automobiles as normally delivered and specified for use in the United States and Canada. Factory options as normally available for a specific model year are permitted. Certain factory and/or dealer installed equipment/ options will move an automobile out of S and into Production or higher so as to maintain the intent and integrity of the Showroom Stock classes. Choose this class if your car has no modifications.
- Production (P) category contains automobiles (as normally delivered to the United States and Canadian public through authorized sales outlets of the manufacturer) plus others with limited performance-affecting changes from stock. In general, you will choose this class if you have minor upgrades to suspension components, “chipped your car”, etc, but you have not added significant performance modifications and the car is still street legal and running on street tires.
- Improved (I) category contains automobiles with more substantial performance-affecting changes from standard (stock) specification, whether changed by the factory, dealer or owner. These modifications have defined limits. These automobiles are classed according to their number of cylinders and actual displacement. Read the PCA Autocross rules to determine if you are running in the Improved or Modified categories.
- Modified (M) category contains automobiles that have performance-affecting modifications outside of the limits of the Improved category and for race automobiles (factory-built or otherwise). These automobiles are classed according to their specified number of cylinders and actual displacement.
- X-Class – Non-Porsche (X) category contains all non-Porsche automobiles. These automobiles are classed according to their specified number of cylinders and actual displacement.
Typical ARPCA AX CLASSES (updated annually in accordance with PCA)
To compete in Porsche classes, your car must have a Porsche Chassis, Engine and Transmission as defined in full rules. This Document is just a guideline and is only meant to get you started. If you have any questions, before you run an ARPCA event, ASK a tech person to help you make sure your car is properly classified.
- Showroom Stock
- S1: 968 (All), 964 Carrera 2 and 4 (1989-‐1994), RS America (1993-‐1994), 986 Boxster (1997-‐2004)
- S2: 993 Carrera, Carrera S, C4S (1995-‐1998), 986 Boxster S (2000-‐ 2004), 987 Boxster (2005-‐2012), 987 Cayman (2006-‐2012)
- S3: 996 Carrera (1999-‐2004), 997 (2005-‐2012), 991 Carrera (2012-‐On), 965 C2 Turbo ( 1990-‐1994), 987 Boxster S (2005-‐2012), 987 Cayman S (2006-‐2012), 981 Cayman (2014-‐On), 981 Boxster (2014-‐On)
- S4: 997S except X51 (2005-‐2009); 991S (2012-‐On), (All), 993 Turbo (All), 987 Boxster Spyder, 987 Cayman R, 981 Cayman S (2013-‐On), 981 Boxster S (2013-‐On), 981 Boxster GTS (2013-‐On), 981 Cayman GTS (2013-‐ On), 991 GTS (2013-‐ On)
- S5: 996 Turbo (Non-‐GT2), 997S X51 (2007-‐2009), 997S/GTS (2010-‐2012)
- S6: 996 GT2/GT3 (2002-‐2005), 997 GT2/GT3/GT3RS (2007-‐2012), 997 Turbo/Turbo S (All), Carrera GT (980:2004-‐2007), 991 Turbo (2014-‐On), 991 GT3 (2014-‐On), 918 Spyder (2014-‐On), Cayman GT4 (2015-‐On)
- S7: Cayenne (2003-‐ On), Panamera (2010-‐ On), Macan all (2014-‐On)
If your car does not fit into Showroom Stock Classes – If you have single adjustable aftermarket shocks Non stock Wheels one inch wider or less than stock – Non stock Wheels one inch bigger in diameter or less than stock – No engine modifications besides an Engine control chip, Air cleaner, Exhaust – Using DOT street Tires with a tread wear rating 180 or higher. – You have a Showroom stock car with under 140 treadwear rated Original equipped Dot tires
Your car can be found in one of the following classes:
- Production
- P1: 356 (All), 912/912E (All), 914/4 (All), 924 (All) P2: 911 (1965-‐1969), 914/6 (All), 924S (all), 924 Turbo (931: All), 944, (All)
- P3: 911 (1970-‐1977), 944S (All)
- P4: 911SC (1978-‐1983), 928 & 928S (All)
- P5: 911 Carrera 3.2 (1984-‐1989), 911 Speedster (1989), 944 Turbo (951: All), 928 S4/GT/GTS (All)
- P6: 964 Carrera 2 and 4 (1989-‐1994), RS America (1993-‐1994); 944S2 (All), 968 (All), 986 Boxster (1997-‐2004)
- P7: 911 Turbo (1976-‐1989), 993 Carrera, Carrera S, C4S (1995-‐1998), 986 Boxster S (1997-‐2004), 987 Boxster (2005-‐2012), 987 Cayman (2006-‐2012)
- P8: 996 Carrera (1999-‐2004), 997 (2005-‐2012); 991 Carrera (2012-‐On), 965 C2 Turbo (1990-‐1994), 987 Boxster S (2005-‐2012), Cayman S (2006-‐2012), 981 Boxster (2014-‐On), 981 Cayman (2014-‐On), 991 GTS(2014-‐On)
- P9: 997S except X51 (2005-‐2009); 991S (2012-‐On), (All), 993 Turbo (All), Boxster Spyder (2012), Cayman R (2012) ) , 981 Boxster S (2014-‐On), 981 Cayman S (2014-‐On) P10:996 Turbo (Non-‐GT2), 997S X51 (2007-‐2009), 997S/GTS (2010-‐2012), Cayman GTS (2014-‐On), Boxster GTS (2014-‐On)
- P11:996 GT2/GT3 (2002-‐ 2005), 997 GT2/GT3/GT3RS (2005-‐On), 997 Turbo/Turbo S (All), Carrera GT (980:2004-‐2007), 918 Spyder (2014-‐On), 991 Turbo (2014-‐On), 991 GT3 (2014-‐On), Cayman GT4 (2015-‐On)
- P12: Cayenne (9PA:2003-‐ On), Panamera (2010-‐ On), Macan (2014-‐ On)
If your car does not fit into the Production classes
Does your car still have the same passenger capacity as delivered by the factory? Does your car have full interior including Door Panels, Dash, Head liner, and Carpeting? Find your class below:
- Improved
- I1: Improved Automobiles (All 4 Cylinder, up to 1999cc); (All 4 Cylinder, 2000cc up to 2499cc); (All 4 Cylinder, 2500cc and above and All 6 Cylinder, up to 2399cc)
- I2: Improved Automobiles (All 6 Cylinder and above, 2400cc up to 3199cc; All Turbo/Supercharged 4 Cylinder)
- I3: Improved Automobiles (All 6 Cylinder and above, 3200cc and above); (All Turbo/Supercharged 6 cylinder and above)
All other cars can be found below:
- Modified
- M1: Modified Automobiles (All 4 Cylinder, up to 1999cc; All 4 Cylinder, 2000cc up to 2699cc; All 4 Cylinder, 2700cc and above; All 6 Cylinder, up to 2399cc)
- M2:Modified Automobiles (All 6 Cylinder and above, 2400cc up to 3199cc; All Turbo/Supercharged 4 Cylinder)
- M3: Modified Automobiles (All 6 Cylinder and above, 3200cc and above; All Turbo/Supercharged 6 cylinder and above)
- X-Class – Non-Porsche (X)
- X1: Non-Porsche Automobiles (All 4 Cylinder, up to 1999cc, 1800 pounds minimum; All 4 Cylinder, 2000cc up to 2699cc, 2500 pounds minimum; All 4 Cylinder, 2700cc and above and All 6 Cylinder, up to 2399cc, 2200 pounds minimum)
- X2: Non-Porsche Automobiles (All 6 Cylinder and above, 2400cc up to 3199cc, 2150 pounds minimum; All 6 Cylinder and above, 3200cc and above; 2700 pounds minimum; All Turbo/Supercharged 4 Cylinder; 2150 pounds minimum; All Turbo/Supercharged 6 cylinder and above; 2500 pounds minimum)
More details can be found in the PCA Parade Autocross Rules Guide: Here