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What class am I/ what am I allowed to modify?

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  • What class am I/ what am I allowed to modify?

    Hi all, I'm very new to this so any help is greatly appreciated, I'm looking to get into autocross next year, and am wanting to do my research before I start adding bits to my car that would affect me negatively in terms of class, or if it's even deemed legal. I have a 1991 Chevrolet S10 that is stock, It would be quite simple to figure out what class that would be, however, I am looking to change the suspension, put on wider tires, see if I can manage the weight distribution better: relocating the battery and fuel tank as far back as possible, eventually getting fiberglass front fenders and hood, ultimately trying to reduce weight from the front end to help it handle better, as well as doing mods to the engine (intake, headers ect.)

    My questions are this:

    1) If I'm racing against my own time (obviously I know there will be lots of cars faster than mine), is there any downside to being in certain classes? maybe fewer runs per day, or specific safety equipment needed for specific classes? ie certified roll cage, fire systems, or harnesses ect.

    2) Are there certain mods I should stay away from? and why?

    Thanks for any and all help!

  • #2
    You are best to google and download the latest SCCA solo rulebook and read through the different classes as running an S10 isn't a common choice. I'll try to answer your questions though...

    1) Runs are all timed, so you have a "Raw" time, and then you have a PAX (time multiplier) based on whichever class you run in. Everyone gets the same number of runs throughout the day. So you need to decide if you want to mod for fun, or mod (or not) to be competitive. Do some research to see if anyone else has run something similar, and what other cars are common in the classes that you could be eligible. Then you can decide if you want to be competitive, or just have fun with your vehicle based on the modifications allowed. For example, I would like to put lowering springs on my Fiesta, but it's more important for me to be competitive in a class that doesn't allow it... think about what's more important to you. Maybe you want to put in different springs and you just have fun running whatever class you end up in, even if you aren't competitive.

    You don't "need" special safety equipment. All you need is to complete a basic "tech inspection" the day of. This usually includes a check to see that there is tread on your tires, your battery is secure, there are no loose items in the cabin, and that the brakes work.

    2) This is up to you. It depends on what class you want to run in. The more drastic the modification the tougher the class (higher PAX multiplier) you end up with. For example, my Fiesta competes in H-Street and has a PAX of 0.780. If I put springs in it, I move to STH, and have a corresponding pax of 0.813. If I put flare s on it, I'm in DSP, 0.842.

    So, if I do a run and my "Raw" time, start to finish is 54.218, then my results once all the scores are calculated and depending on my class, times could be

    HS: 54.218 x 0.780 = 42.290
    STH: 54.218 x 0.813 = 44.079
    DSP: 54.218 x 0.842 = 45.652

    So, if I want to be competitive, then I'd better make sure if I make modifications to put me into STH, then they should allow me to complete a run at least 1.789 seconds faster than if it was in HS, or, I can just be happy with running a car in whatever class it ends up in and enjoy it because I modified it the way I wanted to.
    1994 MR2
    2008 CSX


    • #3
      Thank you very much! that is helpful. I wasn't sure if the SCCA rules were the same all across the board (States and Canada) I'll do some more digging online, but your question about being competitive vs just for fun cleared things up for me, I want to do some mods but would still like to be competitive in the class I'm in, So that will ultimately come down to weighing the pros and cons of each modification as you stated.


      • #4
        You can DL the rules here.

        SCCA is an american organization, but they are usually the rules that are used by clubs in Canada as well.

        One other note is that it seems to me that to be competitive, you need to modify your car almost to the limit of the rule set. So, if you are going to do one mod, you might as well do most of them. That said, tires and driver education are by far the two most effective modifications in terms of cost and results.
        1994 MR2
        2008 CSX


        • #5
          It should also be mentioned:
          1. The club has not allowed any trucks to participate in our events. But if your S10 is low enough and its listed as an acceptable vehicle in the SCCA rules we can discuss it further. I don't want to discourage you, we'd love to have you join us but we need to avoid all rollover risks
          2. We currently do not have a site to actually run an event. The apron at the Pitt Meadows airport is under new lease holders and its really thrown the rental arrangement for a loop. We don't know when or if we'll be running there again.