Quick Links for Autocross Car Classification

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Quick Links for Autocross Car Classification

Postby lowside67 » Sat Sep 26, 2009 10:38 pm

Step #1: What type of class am I in?
The options start with stock class (limited prep, race tires allowed), then street touring class (more prep, street tires required), next comes street prepared (more prep than ST, race tires allowed), and street mod (engine swaps allowed, race tires allowed) and beyond.

SCCA Milwaukee Region offers this useful chart:
http://www.scca-milwaukee.org/Solo/carm ... cation.pdf

If there is ever any doubt, always refer back to the 2013 SCCA Solo Rulebook:

Step #2: What vehicle class am I in?

Stock class possibilities include SS, AS, BS, CS, DS, ES, FS, GS, HS in approximate order of declining speed. Note: Stock Class allows any race tires that will fit on stock sized wheels.

SCCA Stock Class Vehicle Classing:
SCCA 2013 Rulebook (Link Above)

Street touring classes come in 5 flavours: STF, STC, STR, STS, STX, STU. Street touring is unique in that it classes cars differently, based primarily on drive layout (AWD vs 2WD), engine size, etc.

SCCA Street Touring Allowable Modifications & Vehicle Classing:
http://cms.scca.com/documents/Solo_Rule ... cturer.pdf

Street Prepared classes range from ASP to FSP in approximate order of descending performance. Street prepared allows much more modification, race tires, update/backdate, etc. For more information on allowable modifications, refer to the Solo Rulebook above and reference the "Street Prepared" section.

SCCA Street Prepared Vehicle Classing:
SCCA 2013 Rulebook (Link Above)

Finally, Street Modified allows for extensive modification and is broken up into SM (4 seaters), and SSM (2 seaters, and 4 seaters wishing to run with lower minimum weights). For this class, please refer to the Solo Rulebook.

If anything is unclear, please ask!
Last edited by lowside67 on Thu Nov 03, 2011 10:55 pm, edited 3 times in total.
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Postby lowside67 » Sun Sep 27, 2009 12:52 pm

A few modifications and what they do to classing...

Changes to wheels/tires - Only legal in Stock if the exact same size (diameter and width), and approximate offset as stock. If different size, legal for ST, SP, and SM.

Lowering springs/coilovers/rear swaybar change - Not legal in stock, legal in ST, SP, and SM.

Front swaybar change - Legal in stock, ST, SP, SM.

Catback exhaust - Legal in stock, ST, SP, SM.

Delete Catalytic Convertor ("Test Pipe") - Not legal in Stock or ST, Legal in SP or SM.

Carbon Fibre Hood or Trunk - Not legal in Stock, ST, or SP. This is a bump to SM or SSM depending on the vehicle.

Engine Swap - unless covered by the update/backdate allowance in Street Prepared (refer to Solo Rulebook or ASK!), this is an automatic bump to Street Modified assuming the motor came out of the same manufacturer as the shell. If not, the car will go to X-Prepared (well beyond Street Modified).
Example - SR20DET swapped into a 240sx = Street Modified, LS1 V8 swapped into a BMW = X-Prepared.

Interior Carpet Removal - Except for any loose carpet not tied down (ie floormats, sometimes spare tire cover), removal of any interior carpet, sound deadening, etc. is not allowed in Stock, ST, SP, or SM. This is a bump to the "Prepared" Class (this is NOT the same as Street Prepared).
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Re: Quick Links for Autocross Car Classification

Postby alejo98cx » Thu Nov 03, 2011 10:04 pm

Would a Porsche 944 non turbo be allowed in ST? Engine is 2.5L 4cyl... seats 4 (has 4 seatbelts) but the SCAA guide (second link) says no Porsche's are allowed in ST, if this applies to all Porsche's then where would it belong (assuming common bolt-ons and suspension work)?
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Re: Quick Links for Autocross Car Classification

Postby won » Thu Nov 03, 2011 10:32 pm

alejo98cx wrote:Would a Porsche 944 non turbo be allowed in ST? Engine is 2.5L 4cyl... seats 4 (has 4 seatbelts) but the SCAA guide (second link) says no Porsche's are allowed in ST, if this applies to all Porsche's then where would it belong (assuming common bolt-ons and suspension work)?


SCCA hates Porsches. Straight to Street Prepared and beyond!
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Re: Quick Links for Autocross Car Classification

Postby lowside67 » Thu Nov 03, 2011 10:57 pm

won wrote:SCCA hates Porsches. Straight to Street Prepared and beyond!

Actually, that is not true; the 924, 944 non turbo, and 968 are all legal for the newish SCCA STR class and is actually probably not such a bad place to race the car.

Mark
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Re: Quick Links for Autocross Car Classification

Postby won » Fri Nov 04, 2011 11:05 pm

Oops, sorry! Didn't mean to misinform. I just remembered reading about base Boxsters being specifically excluded from STR and SCCA publicly stating that they didn't want "expensive German cars" to dominate the class.
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