GRX: big dreams, little boxes

This is the first post in a new series that is taking a slight departure from the crash-fest that is the bread and butter of YSAR. In these posts, I’ll be writing about my new project: the Generic Racecar Experiment, or GRX for short. In the future, expect to see some crash posts and some GRX posts. Hopefully the two won’t coincide.

I developed a passion for racing cars rather late in life (mid-40s) and now have a lot of catch-up to do. I’ve participated in 18 endurance races to date, but I haven’t tried autocross, time trials, sprint racing, hillclimb, rallycross, or stage rally. On a practical level, I only have so much time, money, and space to allot to this hobby, so I can’t simply buy a bunch of cars and a big tow rig. In fact, I can really only justify one car as I already have a Miata in my garage. Can one car compete in everything from stage rally to the SCCA Runoffs? Well, that’s why this is called the Generic Racecar Experiment.

Absolute Requirements

  • Street legal
  • Race track legal
  • Stage rally legal

There are several reasons why the GRX needs to be street legal. Since rally cars are driven between stages on public roads, they are supposed to be street legal (although many get around this somehow). Another reason is that I hate towing. Driving to the track means that I don’t have to take my unsafe tow rig (Ford Ranger and scary 2-wheel trailer) and I can drive faster than 55 mph (vehicles with trailers have a lower speed limit in California). On the other hand, I won’t be able to bring as much stuff, and I’ll have to really pad the roll cage to make sure it’s safe to drive without a helmet. Street legal also means I can park it on the street in front of my house or grab groceries if my Ranger is acting up.

The main difference between track and rally cars is the suspension. Track cars are low and stiff while rally cars are high and soft. The GRX will either have to swap suspension between events or make a compromise. Thankfully, even though the safety requirements are slightly different between track and dirt, the rules mostly supplement rather than compete with each other. This means it’s possible to build a car for both track and rally without any difficult changes.

Wish List

If you were building an all-purpose racecar, what would you choose? For me, budget is a major concern. Fuel, tires, brake pads, etc. are all cheaper for lightweight low-powered cars. As mentioned above, I plan on driving it to events, so it needs to be able to carry race tires, tools, and camping equipment. I want to put a telemetry system in the car, and this is much cheaper to do if the car has CAN bus, which is in all US cars from 2008. From a practical standpoint, I already have several sets of 15×7 4×100 Miata wheels, so it makes sense if the GRX uses the same dimensions. Lastly, one of my main goals is to compete in the SCCA Runoffs in 2018, so it needs to fit in some Runoffs class.

  • Inexpensive to build, maintain, and race
  • Enough storage to bring tools, spares, and gear to events
  • CAN bus
  • 15×7 4×100 wheels
  • SCCA Runoffs class

Admittedly, it’s hard finding a car that meets all these criteria.


For the Generic Racecar Experiment, I chose a Toyota Yaris. A what? Yes, a 1.5 liter FWD econobox with 106 crank HP. There’s a racing class for these little cars! The SCCA B-Spec class pits the following cars against each other: BMW Mini Cooper, Chevrolet Sonic, Fiat 500, Ford Fiesta, Honda Fit, Kia Rio, Nissan Versa, and Toyota Yaris. Each model has its own upgrade kit. A combination of race weight and restrictor plates is used to achieve parity among the vehicles. The Yaris has the least expensive kit. Just shocks and springs. Not even an anti-roll bar. This puts the Yaris at a bit of a disadvantage for handling, but it does have one of the lightest race weights at 2425 lbs. Having such a simple race kit also keeps the build as inexpensive as possible. Here are the classes I can easily race the GRX in.

  • SCCA: B-Spec (Road Racing), Stock Front (RallyCross, RallyTrials), FWD under 2.5 (Rally Sprint), STF (Solo)
  • NASA: PTF (Road Racing), TTF (Time Trial), Stock Light (Rally Sport)
  • Rally America: B-Spec (Stage Rally)
  • CRS: Stock 2WD (Rally Cross), Performance Stock (Stage Rally)


So what exactly does one need to build a B-Spec Yaris?

  • 2007+ Toyota Yaris
  • Crash Safety: roll cage, cage padding, seats, seat brace, harnesses, window net, center net
  • Fire Safety: fire system, fire bottle, kill switch
  • Driver Amenities: quick release steering wheel, wide angle mirror, cold box, hydration
  • Performance Parts: suspension, brake pads, crash bolts, filter, exhaust, wheels, tires
  • Electronics: telemetry, camera, radio
  • Miscellany: ballast, labels, tow hooks, hood pins, inspections

Here’s a Car & Driver video about professional B-Spec builds. Each build adds $10-20k to the $15-20K vehicle price tag. Total price for each racecar was $25,000-35,000. Of note, none of them are actually legal! Can the GRX compete with these cars while costing less than 1/3 the price? Again, that’s why it’s an experiment.

Stay Tuned…

  • For build details
  • For a complete list of parts and expenses
  • For testing and tuning experiments
  • For autocross
  • For hillclimb
  • For rallycross
  • For time trials
  • For endurance races
  • For sprint races
  • For stage rally
  • For more crash videos (hopefully not me)
  • For more bullet points

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