Corvette - The Ideal Race Car - Interview with Steve O'Hara
Steve O’Hara has won 9 national karting championships, raced in the Formula Atlantic series and battled some of the biggest names in racing history. He is acknowledged in the vintage karting hall of fame for innovations in the sport as well as his flawless race craft and ability to think outside the box. After 50 years of racing, these are his thoughts on how the average guy should build a Corvette.
Reduce Drag
“Drag reduction is a no-brainer,” he explains. “You take door handles off, close up openings, eliminate parasitic drag with objects sticking out, put a flat floor in the car to clean up air underneath it, reduce the grill opening to only what’s necessary for cooling and no more. These are all things that you don’t need to be an aerodynamicist or have a wind tunnel in order to accomplish. It’s the functional equivalent of gaining horsepower. With spoilers, diffusers, and wings you need very specific angles of attack, sizes, and placement to be effective. For the average guy without a wind tunnel getting it wrong means large drag without any real downforce. If you focus on reducing drag you’ll increase your top speed and get there faster.” Great advice!
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Reduce Inertia
Now you put your car on a diet according to O’Hara, “You want to focus on reducing inertia. Go-karts maneuver around corners really fast because they don’t weigh anything. Reducing drag makes you faster in a straight line and reducing weight gets you around corners faster. Those are things the average guy in his garage with limited resources can accomplish.” He advises against the track day mantra of buying a rear wing and a front diffuser. “You’re just shooting in the dark if you try to copy what you see. Aerodynamics are incredibly sensitive.”
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Case Study
He goes on to explain how in the Atlantic days he was involved in a development program for Swift racing cars under the famous designer David Bruns. The company was seeking aerodynamic gains by updating the underbody “tunnels” for more downforce. Bruns, a designer of CART winning open wheel cars had to make changes to keep up with rivals Reynard and Ralt. Swift sold a underbody update kits to customers that was a total failure. Steve laughs, “to this day the original tunnels on a Swift DB-4 are still better than any substitute that came along.” The tunnels became hyper-sensitive to as much as 1mm of ride height change.
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Manage Brake Temperature
“It’s important to maintain brake temperature,” Steve said rather simply. “Brakes that are built for the street aren’t made for racing so ducting a lot of air to them is critical,” says the racer with 5 decades of experience. Anyone who has experienced brake fade or even failure can attest to how important this advice is. Some readers may be thinking this is an obvious bullet point, but formats like endurance racing can push a car far beyond what might work in a 20 minute track day session.
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Springs and Shocks
These are one of the most modified parts on any enthusiasts car. Steve again had some interesting comments for those reading. “Springs and shocks do absolutely nothing when you’re going in a straight line. People think it’s the most critical thing. You’ll improve the car through a few key cornering sections of the race track to boost average speed, but they only help in certain areas. They don’t help in straight line, top speed and rate of acceleration coming off of a corner like drag and weight reduction do,” he concludes. Of course, they are important, but the format of this interview was to see the order of importance in a build.
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Setup
So what’s the last thing? Steve begins to wrap up the conversation, “Actual setup. Things like camber, caster, and toe. While these can help the car, unfortunately, these are things that often track specific. We all know that the settings we would use at Willow Springs are not the same settings we would use at Chuckwalla or a tight twisty track with lots of stop-and-go chicanes.” At higher speeds, you can build instability with these type of settings. Whereas a format such as an autocross, you'll need the car to transition quick and some instability can actually be a good thing.
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Engine Tuning & Gear Ratios
“Now you start moving into the realm of engine tuning and gear ratios,” he recalls about his experiences in the past. “We were changing gear ratios in my Atlantic for every track and if you were to ask me this same list about that car the priority list changes completely.” This guy knows his stuff. Tailoring your gearing to each track if possible is essential to produce the best lap times!
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Here is my garage
You know what I like more than driving race cars? Knowledge. This was a fun interview that aims to help you see tuning in a different way. I hope you learned something and I’ll continue to do more interviews with him if there is interest. His understanding of downforce is substantial and he has a genuine love for motor racing! Parked next to his Swift DB-4, among several other karts and a vintage Formula Ford is a perfectly restored Chevelle. Proof that the best drivers are Chevy guys. See you next time.
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