2022: Time Trials?

I’m thinking ahead to possibly competing my Z3 in time trials next year. Looking around at the various series that exist in Northern California, I find the following organizations. I’ve made some notes about each.

    • The Z3 would be in the non-M class. Literally, all non-M cars regardless of engine size, model, year, etc. There is of course the M-class for all M cars regardless of performance. I’m not sure any events are running in Norcal.
  • NASA
    • The Z3 would go in the TT6 class. This includes actual race cars on actual race rubber. I don’t mind competing against Spec Miatas, but I don’t want to do it on slicks. That’s too much money and also I would need a race seat to deal with the Gs.
  • NCRC
    • 13:1 weight:power ratio is the slowest class. I’m not sure how they calculate weight or power. With the factory numbers (2690 and 138) I get 19.5:1. If I calculate actual race weight and wheel hp, it’s about 21.5:1. These are a long way from 13:1.
  • OnGrid
    • Their slowest class includes the Honda S2000. That’s a lot faster than a 1.9 Z3.
  • SCCA
    • See below
  • Speed SF
    • My Z3 isn’t in their class calculator, but I’d surely be in the bottom class, which has a lap record that is about 7 seconds faster than my Z3. I’m sure I could put aero and sticky tires on my car and drop a couple seconds, but there’s no way I’m getting to 1:25 at West.
  • Speed Ventures
    • They run several time trial series and have the Bimmer Challenge for BMW cars. The slowest class includes E36 M3.
  • Tracktime
    • Not truly a time attack, but something called Handicapped Pro Racing. Slow cars start before fast cars and they are timed to get to the finish about the same time. Sounds like fun, but also dangerous as there are essentially no safety requirements.
  • Turn 8
    • Classing based on prep level not performance. A Spec Miata would be in a higher class than a C8 because it has a cage. What a weird way to class cars.

First off, I can’t believe there are so many organizations offering competitive lap timing. I’ve probably even missed a couple. My 1.9 Z3 isn’t competitive in any of these organizations except SCCA.


My local SCCA chapter, San Francisco region, doesn’t do time trials, but the Reno region does. They run most of their events at Thunderhill West, which is my favorite track. So this is one very good reason for driving with SCCA Reno.

A stock 1.9 Z3 fits into the Sport 6 class. Other cars in this class include econoboxes like Honda Fit and Ford Fiesta, sporty FWD coupes like Acura Integra GSR and VW Corrado, and low-end sports cars like NA/NB/NC Miatas and FRS/BRZ/86. In what universe is it fair for a Toyota 86 to compete with a Honda Fit? This is some of the dumbest classing ever.

As it turns out, my Z3 isn’t legal in S6 because it has adjustable suspension and an ECU tune. That means I would have to class it in the Tuner 5 class. Let’s see what else is in that class: B-Spec cars (Honda Fit, Toyota Yaris, Ford Fiesta, etc.), older Miatas (NA/NB), and E30s. The E30 is going to be a couple seconds faster than the B-Specs but as a whole, the class isn’t a shit-show, and I would be happy to race my Z3 in T5.

SCCA also has the Max category. The lowest class is M5, which has a 1.9L cutoff. At 1895cc, the Z3 would compete in M5. The Max category allows for engine work (e.g. cams) and aero (wing & splitter). If I did those things, I could probably compete in other time trials series as well. However, my Z3 spends most of its life as a street car and I don’t want it to become a full race car.

Mk4 GTI?

My racing buddy Tiernan has two Mk4 GTIs. Let’s not discuss why anyone would own 2 Mk4s but rather what class they would be in, and which cars they would compete with.

In the Sport series, a Mk4 GTI ends up in S4. Note that this is 2 levels up from the FRS/BRZ/86, despite having less power and more weight. In this class, you will also find the classic German battle between a Porsche Cayman and a BMW 318is. Wait, what? Truly. A base model 2012 Cayman has 265 HP and a BMW E36 318is has 138. Somehow they are in the same class. Looking over the cars in S4, it’s even more stupid than S6.

Once again, Tiernan’s GTIs have adjustable suspension so off to the Tuner classes they go, to the tune of T4. The competition here includes some other FWD turbos like the Fiat 500 Abarth, Ford Fiesta ST, Ford Focus ST, and Mini Cooper S. Don’t get too excited about a level playing field because T4 also includes E36 M3, NC Miata, ND Miata, Boxster, and S2000. Oh, and on the low end it includes the Ford Crown Victoria. The S2000 and P71 make about the same HP but the cop car weighs ~1200 pounds more. Sounds fair.

If I had a GTI, would I rather race it in S4 or T4? Both classes are a such a mess that it hardly matters. I guess I would go with T4 so I could make a few modifications if I wanted to.


The main problem with the Z3 as a time trial car is the seats. They just aren’t very supportive. Do I want to get actual race seats or try to invent some kind of bolstering for track days? Hmm, the inventor in me says to make something…

9 thoughts on “2022: Time Trials?

    1. I generally like NASA TT rules, but they stop classing at 18:1. My modifiers are: +0.6 for higher than 100 TW, -0.7 for A-arms, +0.4 for BTM aero, -0.1 weight. That puts me around 22:1, which would make a TT7 if they had one. In order to be competitive in TT6, I would have to do a lot of upgrades.


      1. 19:1 now. And they’ve made enough changes for the upcoming season that an intake and tune in my sloppy slow Miata may actually make it mid-pack competitive. A 2300lb NA with a spoiler and 200s has about a 114hp cap.


      2. This year’s 19:1 is a lot like last year’s 18:1 because they give more bonuses (mechanical throttle body, tire width, tire compound). I don’t think many of the cars previously in TT6 would be reclassed to TT5. If I race on Hoosiers and mount a wing, I would still be allowed an average of 135 hp. My average hp is probably 118, so I’m giving up a lot. More realistically, I would use the 200TW VR1 tires I already have and not mount a wing, which would allow me 154 hp. That’s a better fit with the 2.5L Z3.


      3. Looking at the compliance docs, it looks like they are converting from whp to bhp. A Miata with 122 peak hp gets booked as 130 average hp. So maybe TT6 is fine after all.


      4. Yeah, it was designed to make Hoosiers less appealing from what I’ve heard. Where are you seeing the HP info btw? I was looking at 6.3.1 Definitions that doesn’t seem to have changed:

        1) The “Adjusted Weight/Power Ratio” for each vehicle will be calculated based on a simple competition weight to average chassis dynamometer (Dyno) horsepower ratio (Wt/Avg HP), followed by the adjustment of the resulting ratio by adding to, or subtracting from it, based on the list of “Modification Factors” below.


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