Qualifying was underway for the 1995 Daytona 500, and the buzz around the track wasn't just the roar of stock cars turning laps. The sound drawing attention around Daytona International Speedway was, in fact, closer to a high-pitched whine, something associated more with Indy cars than stock cars.
As Sterling Marlin drove the yellow No. 4 Chevrolet of Morgan-McClure Motorsports around the track, the car's sound had the attention of television crews, print journalists, and spectators.
Runt Pittman, the team's master engine builder, had found a new trick for restrictor plate engines, many reasoned. The distinctive sound made by the car was all the evidence needed. Further proof came when Marlin won one of the Twin 125 qualifying races. Then Marlin won the Daytona 500 for the second straight year, further validating Pittman as a top-flight engine builder.
Pittman had, no doubt, built a strong engine, putting him and the Morgan-McClure team at the pinnacle of the sport. But what about that distinctive sound?
Today that high-pitched whine is common at restrictor-plate tracks, and there's a story behind how that came to be.
Sound And FuryThe folks at Morgan-McClure, in late '94, were experimenting with their exhaust systems, trying to gain an edge, and trying to give Marlin the chance to do what only Cale Yarborough and Richard Petty had ever done-repeat as Daytona 500 champion.
Mark Giles, exhaust fabricator for the No. 4 Chevrolet, had contacted Boyd Butler just weeks before qualifying for the Daytona 500, asking if Butler had ovalized pipe that would work in Winston Cup. Butler, who owns Dr. Gas Exhaust Components, sent the team a set of pipes. Giles found a combination he liked, and Butler was soon boarding a plane.
"Larry McClure calls me on the phone and says, 'Boyd, put every piece of tubing you can carry in your luggage and get back here right now.' So I did just that," recalls Butler.
After two days working with Giles to develop an exhaust system for the team, Butler headed back home to Utah. Before he left, dyno readings showed a gain of 411/42 hp using Butler's custom-made exhaust system.
"I don't want to take anything away from Runt Pittman, because he was building great motors," says Butler. "He might have won the Daytona 500 anyway, but they went down there with a great motor that had 411/42 hp more than it had the week before. To just stick this on the back of the headers and gain 411/42 hp is unthinkable."
Under PressureButler's Dr. Gas exhaust system has been fine-tuned without undergoing drastic change in the time since Marlin's odd-sounding Daytona 500 winner hit the track over seven years ago. Butler has worked to improve the bends and shapes of his pipes, although the hole sizes and basic layouts of his system are the same.
There are several basic tenets of Butler's system, all built on ideas and methods perfected over the years in his quest to build better exhaust systems. One of the foremost beliefs he has developed is that backpressure in an exhaust system is never good.
"If you have a case where backpressure in the exhaust system causes the motor to make more power, it's because there are other problems in the motor that have to do with tuning, such as primary valve timing, which is dictated by the camshaft and rocker ratio," Butler says.
"What happens is, if you have a very efficient exhaust system and you lose horsepower with it, frankly, what it's doing is it's stealing some of the intake charge off of the exhaust during the overlap period (created when cylinders fire on opposite banks inside a V-8 engine)."
Primarily through the use of crossovers that tie pipes from each bank together, Butler's system focuses on reducing backpressure and efficiently moving exhaust from an engine