Sometimes your subconscious makes choices that you aren’t 100 percent aware of. And over the last two seasons, I have experimented in several racing series. With nothing quite feeling right. There was always this nagging, ‘this ain’t it’ feeling, no matter how I approached the matter.
After my official exit from 944 Spec, I had to get things right this time around. I have always raced low-cost production cars. Think Porsche 944’s and Mazda Miata’s. So I started thinking outside the box. What if there were a low-cost tube chassis racecar? And that is just what I have found in the Thunder Roadster.
What is the Thunder Roadster?
The Thunder Roadster is a purpose-built, tube-frame, open-cockpit racecar. With a fiberglass body, the car can weigh as little as 1500 lbs in race trim. It was initially developed by INEX, which is the same company that produces the Legends racecar. And both the Thunder Roadster and Legends car share a ton of components, making parts cheap and easy to find.
Power-wise, there are two official prep levels, although a more open ruleset can be used in Super Touring. Prep level 1 runs old Yamaha air-cooled motorcycle engines and can weigh as little as 1500lbs. In prep level 2, the race weight is increased to 1600lbs, and the engine is swapped for a more modern, liquid-cooled Hayabusa motor.
In effect, the level 2 car is significantly faster with a power-to-weight ratio falling close to the 10 to 1 mark, with the prep level 1 cars being between 15 to 1 or 13 to 1, depending on engine health.
But that doesn’t tell the whole story, as there are a ton of prep-level 1 cars out there for sale for less than 10k. So when I saw the local listing for this well-sorted, hybrid liquid-cooled, Yamaha-powered Thunder Roadster, I jumped at the chance.
I mean, where else was I going to get a 1500lb racecar with a sequential shifter for under 10k? Like seriously.
First Impressions
I have raced the car twice at this point, once at Nashville Superspeedway and again at Barber Motorsports Park, and umm… to say I made the right decision is an understatement. For perspective, one of my fellow racers came up to me after the first event and said, ‘I don’t think I’ve seen you smile this season. Glad you like the car.’ Because the reality is, even at what is probably a 15 to 1 power to weight, this thing is way more fun and engaging to drive than I ever could have imagined.
At Nashville, once I got used to the fact that you do still have to use the clutch on the sequential box and that it is impossible to heel/toe with the current pedals, I began to find pace in the car quickly. Even though the top speed on the straight was only 110 mph, or about as fast as a 944 Spec, I was consistently 3 seconds faster than my previous ride. Where this car lacked in outright speed, it made up for it in handling, where I would gobble up cars in the infield.
During the Aussie pursuit, I would go from 14th to 2nd. Making for quite a ride. And securing 1st in class against a few heavy-hitting horsepower cars. (BMWs and Fords)
Thunder Roadster in Super Touring 4
I will discuss the Barber event in a separate post. I am still learning the car and making mechanical improvements that are outside the scope here. Regardless, this season I am campaigning the car in Super Touring 4. The prep level 1 car is allowed in ST4 if the wing is not run. And with the current horsepower, a wing would most likely result in slower lap times anyway.
However, I do have room to improve power and take this car to the pointy end of the field in ST4, so I will be documenting that process. The one drawback of the vehicle is that documentation is sparse. I am working on changing that.
Prep Level 2 GTR and TRX
I have a lot of plans around this chassis, and the second one I ended up buying. The current car will remain Yamaha-powered, and I am optimizing the platform for Super Touring. The other chassis I picked up has a blown motor. It will get the Hayabusa treatment to either run in the Spec series or the Southeast TRX class.
Thunder Roadster Knowledge Base
As I mentioned, documentation is sparse, and I will be building assets to make things a little easier for everyone. I believe there is a massive opportunity in this class to keep the prep level 1 cars alive and offer an insane entry-level performance per dollar class for those interested. And then document the conversion process of the second chassis to Hayabusa power to take the mystery out of these builds.
