The Spring that Revolutionized Nascar

Travis Road is one of a hundred dirt lanes that road crews in this part of southeastern Michigan haven't gotten around to paving. On this late November day, a cold, steady rain has enlarged the potholes into craters that bounce my car as I approach a large, nondescript metal building. It's the kind of obscure facility that's sprinkled across the older suburbs of Michigan, Ohio, and the rest of the car-building belt of the Midwest. GM's Milford Proving Ground is 10 miles to the north, the border of Detroit 25 miles to the south. A small sign outside says PSI SPRINGS.

Inside is the guy everyone says I need to talk to, Steve Bown. He is tall, with wide shoulders and noticeably broad hands that make him look more like a tight end than someone who devotes his waking hours to the minute details of valve springs. He drops me off in the conference room and leaves to fetch his partner, Larry Luchi. And then I spot it on a dusty shelf: a heavy, slightly blackened coil mounted on a small piece of wood. A plaque underneath reads "Jeff Gordon, 1998 Rockingham Win." This tube of steel wire was the first PSI valve spring used in a Nascar race. It revolutionized engine building and the country's most popular motorsport, but few people have ever heard of it.

My interest in the subject began with a remark by legendary Nascar team owner Jack Roush. This was 15 years ago. I casually asked him if there was a single automotive part with the potential to dramatically alter racing stock cars. Roush isn't in the business of disclosing trade secrets, but he lit up. "Oh, yeah," he said enthusiastically. "Valve springs. We're getting higher quality valve springs that are going to let us do some tremendous things." It was an unexpected answer: These springs are humble engine parts. They simply keep the valves to the combustion chambers closed until the moment that a fresh dose of mixed fuel and air has to enter, or exhaust leave. Roush wouldn't elaborate?maybe he thought he had said too much already. Intrigued, I called other Nascar teams. But racers are as tight with their secrets as the NSA. I got a bunch of "no comment" answers and moved on.

Recently, Nascar's big rules change for 2012?a switch from carburetors to electronic fuel injection?made me wonder whether the innovations Roush hinted at had really changed the sport. I dug back into my contacts among Nascar team owners and engine builders. This time I was able to get people to talk. The highly publicized switch to fuel injection was a sideshow, they told me, in comparison with the changes in engine performance that occurred between 1998 and 2004. During those years, horsepower and engine revolutions had reached once-impossible heights. To understand how, I needed to ask Steve Bown about his valve springs.

Bown and Luchi return to the conference room, where I am contemplating the Jeff Gordon spring. "We were in the pits during the race," Luchi says. "Keeping our fingers crossed watching the 24 [Gordon's] car." It wasn't a particularly exciting race. Videos show Gordon hanging back for most of the contest but clearly dominating the final third of the race. At one point he has a 4-second lead. Gordon had just won the 1997 Nascar championship, and fans had no reason to suspect that anything other than driving skill was at work. But Nascar engineers knew. Inside his engine, 16 newly designed valve springs were ticking away, giving him an advantage. "By 2001," Bown says, "all the teams were using our springs."

Rules governing Nascar engine architecture date back 50 years. They have evolved, but the basic regulations that limit engine size to 358 cubic inches and define the layout?two valves per cylinder and pushrod valvetrains?were written in 1968. For that reason, Mike Fisher, Nascar's managing director of research and development, has a strange job for someone with his title: keeping a lid on innovation. "We try to maintain a pretty tight box around what teams can do to the engine," he says. "We don't want one team having more power." If the details can seem backward, like running carburetors and burning leaded fuel decades after passenger cars had moved on, there's a certain genius to the strategy. Nascar grandstands are packed partly because, in any given race, there are at least a dozen drivers who could win. In terms of lead changes and tight racing, a Formula 1 race is, by comparison, a procession.

Despite the straitjacket rules, however, Nascar drivers, engineers, and mechanics have always hunted for ways?some legal, others not so much?to get a performance edge. Counterintuitively, massaging the old tech of the Nascar V-8 at the granular level has produced highly advanced engineering. When it came to engine design, though, there was always one weak link. "The vast majority of engine failures?85 to 90 percent?are caused by broken valve springs," says Cecil Stevens, a longtime engine builder who now heads the engineering consulting firm Illusions Engine Development. The reason is simple: Valve springs have an incredibly tough job.

At each of the engine's eight cylinders, the intake valve lets in fresh air and fuel, and the exhaust valve releases spent gases?16 valves in total. A spring holds a valve closed until the valvetrain system pushes on the top of the spring, forcing the valve to open. Since an engine's output is directly related to the amount of air that flows in and out of the combustion chamber, the valves play a vital role. The larger the valves, and the farther they open, the greater the airflow and the horsepower the engine can produce?and the greater the stress on the spring.

As much as airflow dictates engine power, so does the speed at which the engine operates. Spin an engine faster and it will, in most cases, make more power. Randy Dorton, the chief engine builder at Hendrick Motorsports, Gordon's team, started a quest in the early '90s to increase engine rpm. Dorton died in a plane crash in 2004, but Jeff Andrews, who is now Hendrick's director of engine operations, has been at the team for about 20 years.

"Back then," Andrews says, "the biggest limiting factor [for higher engine rpm] was the valve springs." In 1998, a stock car's V-8 peaked at about 8000 rpm. The valves cycle at half the speed of the engine's crankshaft, so at 8000 rpm the valves open 4000 times per minute, or 67 times each second. During many oval races, engines remain at peak rpm for 500 miles?and the valve springs were operating outside their comfort zone.

The springs were a commodity product. Teams bought them from companies whose steady clients were mainstream carmakers. One such company is Peterson Spring, a privately held automotive supplier founded in Detroit in 1914. Dorton approached Peterson about building better valve springs. The company made some improvements, but it simply wasn't focused on racing. While there, Dorton met Peterson engineer Steve Bown and ultimately convinced him that there was a need for a company that focused on racing valve springs. Bown enlisted Larry Luchi, a former Peterson CFO, to handle the business details while he focused on design and manufacturing. In 1996, with $170,000 of startup capital, the two men formed Performance Springs Inc. (PSI). "During our first year, we had one customer," Luchi says. "Hendrick Motorsports."

Source: http://www.popularmechanics.com/cars/news/vintage-speed/the-spring-that-revolutionized-nascar-6643778?src=rss

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