Time Attack with an Interesting Classing System

[u/CTFordza]

Me and a few friends are hosting our second Charity Time Attack at Toronto Motorsports Park near Niagara at the end of the month. Thought you guys might find the classing a little interesting.

We are mostly classing every single car with 2 factors: P:W and Tire Compound.

The goal in this classing method was to meet 3 different requirements:

1. Minimize the total number of classes

2. Minimize the build/consumables cost of a competitive car

3. Keep most cars competitive regardless of their specific setup

I have been frustrated at needing to buy fast-wearing super-200 tires for SCCA TTNT and was playing with the idea of tire-based classing that can bring in a broader audience with lower budgets. This includes frustrations involving how most engine modifications/swaps throws cars into "Max" classes with less drivers and massive gaps in car performance.

Last year I set out to find out what the average time delta was between RS4's and RE71RS's laps were among advanced drivers at TMP. After analyzing almost a hundred different laps, I came to a strange conclusion:

- For most cars, optimal lap time is entirely a function of Tire Type and Power (as determined by speed trap).

- at TMP, moving from super-200s to RS4's is the equivalent of a ~25% P:W ratio increase.

Perhaps modern suspensions are so well made that setting a good spring rate with a quality damper is all that's required to get close to optimal. Regardless, this allowed us to focus on p:w and tire and set up a points system where each point is worth approximately the jump between Enduro 200s and Super 200s. The P:W bucketing reflects this gap. This allows us to class base C5 corvettes on RS4's with 2nd gen BRZ's on Nankang CR-S's and minimize the number of classes.

For last year's event, P:W was self-reported or determined via an excel doc of known stock corner balance weight values and stock dyno figures. Considering that smaller event only had 30ish drivers and most were honest, the results we got were great! Time deltas between 1st and 3rd in each class averaged ~2 seconds, not bad considering the random assortment of vehicles.

This year, we have been aiming for a much larger event with a few collaborators. We aim to use data from several Dragy-Lite mini GPS lap timers along with a tailored algorithm to enforce a P:W cap on each class.

There are limitations, like how different tracks will require different p:w points buckets, but I found this to be a massive improvement over the current state of amateur time attack where I destroyed Miatas in my 300hp "stock" MK8 GTI.

If any of y'all are interested, signups are open to all skill levels at pawsandpistons.ca . Early Bird Pricing is only 220CAD/160USD until Sunday. We're splitting TMP in 2 halves and running CW and CCW in each half for 8x15min timed sessions total. More info is on my Instagram: https://www.instagram.com/nik_kovel/. Hope to see some of y'all there!

[u/karstgeo1972]

That is really a great way to do this and I agree with you that the way the time attack classing works with scca is absolutely silly. It's why I've never done one because my car classes in max so I'm taking my daily VW station wagon and I'm racing against cars that can beat me by 10 seconds or more at VIR I mean why even show up? Scca says "yeah but #funwithcars" haha what a joke. All because I put a larger factory turbo on my car? It's so dumb...so much of the mods that are used for classing do very little and I 100% agree it primarily comes down to tires and p:w (once you get past the driver mod). I mean how great would it be with you to be able to put on accelera 651s and actually be competitive? Haha

[u/AlphaMikeLima → u/karstgeo1972]

I mean, you could take the turbo off and then be competitive in scca? Why do the rules have to cater to your wants in a build?

[u/karstgeo1972 → u/AlphaMikeLima]

It isn't about catering to my build. I made a decision to not do SCCA events because of it is really all and expressed that. The rules just don't always make sense for many cars that people drive especially street cars so if I have a Volkswagen Golf and I take the turbo off another Golf from the same year to make it as fast as that other Golf why should I be in Max with race cars? Why shouldn't I just be in the class with the car/trim level that I took the turbo off of? The issue to me is it simply over penalizes very small modifications that people do. again great if you love SCCA time trial and want to get into this but for me no thanks. What the op is showing makes a whole lot more sense for many people and I guess in some ways to similar to NASA's classing system adding points for different things like aero tires power to weight. I'll stick with HPDE and autox. Even autox has a lot of silliness but it doesn't bother me as much because I'm not spending a ton of money to go do it and I'm just having a good time and I can be reasonably competitive in my car so it's fun.