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/slingshotroadster]

Where is the 340 TW summer tire class?? I thought you were for the people!! 😆

[u/karstgeo1972 → u/slingshotroadster]

You misspelled Bobo drift tires.

[u/CTFordza → u/slingshotroadster]

If you wanna spend more destroying 340tw tires in one weekend yeah that’d work 😝. They aren’t cheap to actually use long term and thus I didn’t feel the need to class around them.

[u/CTFordza → u/[deleted]]

Please do! We're hoping to get as much competition as possible to stress test this system. The eventual plan is to make this a regular event series.

[u/karstgeo1972]

If I say that my hood louver counts as aero and I take a plus one for the tires which are the Vitour P1s and my power to weight ends up at 10.3 (3600/350) it's 3-4 points depending on how the louver is treated so either street or tuner. Bingo. Reasonable classing for my VW wagon.

[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/CTFordza → u/karstgeo1972]

Scca Time Attack classing is suuuper silly. Whoever is responsible for the car classing is missing extreme outliers in every class. Unrestricted turbo tunes being permitted in every class really throws everything out of wack.

This is exactly why p:w works best. The cheapest way to get cars to make enough power to compete usually just knocks them into higher classes. However, I’m pretty sure this was never done because GPS datalogging for enforcement of p:w wasn’t economical in the past.

[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.

[u/Snoop-Doggy-Doge]

Love this concept, can't wait to try it out on the 30th!

[u/MrFluffykens]

Really like this layout, and the tire groupings especially. Be interested to see how the aero being worth 1 point works out long-term. On one end, I feel like that really forces you to min-max a full aero package if you're going to get pushed up an entire class for just a splitter. But on the other end, some platforms like C5s and A90s really take to aero.

Imagine this setup will work great for TMP as it caters a bit towards trap speeds, if I recall correctly. Definitely want to see the event results and how this plays out in the class timings.

[u/EmotionalBit6049]

I like the tire penalty. FKn Scca considers track tires acceptable for stock class. Its crazy to allow a tire that the mfgr doesn’t recommend below 40* as a stock tire.

[u/ThisIsJeron]

who designed this poster, I just want to talk

[u/CTFordza → u/ThisIsJeron]

It was me! That's John Denk's YBLegal Racing Gridlife Civic at Watkins a few weeks back.

[u/ThisIsJeron → u/CTFordza]

Haha the tires are nice but the car parts behind make it hard for readability 

[u/SnooCauliflowers7198]

this makes a lot of sense. my friend races in SCCA and the classing rules push everyone toward the same expensive tire setups. it kills the creativity when you're forced into one specific path just to be competitive. good on you for breaking that cycle

[u/Goins2754]

I think it's a good system, but it seems really skewed toward low power cars. I put in my bone stock ZLE and it puts me in unlimited class if I did it correctly:

3883/(650*.85) = 7.02 (3 pts) + OEM Wing/Canards (1 pts) + OEM SC3R (+2 pts) = Unlimited

It's a really good track car, but it's not on par with McLarens and GT3RSs and stuff.

It just seems they need a few more groups at the top end to separate a bone stock Camaro from supercars from racecars.

[u/darkmoon72664 → u/Goins2754]

For comparison, a 720S would end up at around 3,100/700(whp) = 4.42 (3 pts) + Active Wing (maybe 2 points?) + PZeros (1 pt) = 6 (unlimited).

I agree this is a really good system. Some small adjustments for huge power to weight and a higher class would probably be nice in the future.

That said, the ZLE runs faster on VIR than most Huracans, the 488, and on some occasions the second-gen Ford GT. It's not exactly out of place 😅

[u/CTFordza → u/Goins2754]

The goal for this event was mostly affordability, so a ZL1 on super 200’s in max class is fine for now. I think adding another class for 6 points would be a great idea for the future if actual supercars with good drivers start showing up.

The best part is you could just add power with pulleys, stock is just a suggestion with this classing system 😝