TBT: The Infamous Restrictor Plate Race
This year, New Hampshire Motor Speedway celebrates its 25th Anniversary. Throughout the year as part of that celebration, the Granite Stripe will throw it back on Thursday and give a small history lesson on past events at the track.
The above photo is a restrictor plate being installed on a car. Not just any restrictor plate, but one being placed on a car before the Dura Lube 300 at New Hampshire International Speedway on Sept. 17, 2000.
The plates were put on the cars at NHMS for the first (and last) time during this race. Earlier in the year, Adam Petty and Kenny Irwin, Jr. passed away in separate racing incidents at Loudon. In both instances, reports stated that the throttle stuck entering Turn 3 and the cars hit head-on in a time before SAFER barriers. While adding the plates didn't address the throttles, it did regulate top speeds on the tight track and it was believed that would make the race safer.
How does it work?
A restrictor plate limits the amount of air flow into the engine, which in turn regulates a car's top speed. They're currently used at superspeedways, like Daytona and Talladega, where cars can go unsafely fast (yes, that sounds ironic in racing). They're what cause the pack-style racing at those tracks.
However, restrictor plates not designed for one-mile, paperclip tracks, like NHMS ("NHIS," as it was at the time). The notion that it's impossible to pass at NHMS is far-fetched. Just this past July, Brad Keselowski's crew chief, Paul Wolfe, threw track position to the wind and kept shuffling his driver back in the field by taking four tires. He knew Keselowski had the car to race his way up front again on four good tires, and sure enough, he led a race-high 138 laps en route to the win.
But, passing at NHMS isn't simple. The track isn't wide enough for a driver to move around and try different lines, like they do at larger intermediates. Passing takes a confident driver in a faster car.
In the case of the restrictor-plated Dura Lube 300, no one had a faster car than anyone else due to the regulation. The track doesn't lend itself to pack racing or drafting, so the race turned into a lengthy game of Follow the Leader.
Jeff Burton started on the front row alongside pole sitter Bobby Labonte, and immediately jumped to the front. It proved to be a wise decision to make the move early. Burton would go on to lead all 300 laps in what will forever be remembered as the most dominant and least exciting Cup race in Magic Mile history.
The NHMS restrictor plate experiment was scrapped after the race ... sort of. The NASCAR Whelen Modified Tour continues to use them to this day at NHMS, but the ground-pounding aerodynamics of those cars allow for drafting that isn't comparable to the stock cars in the Cup Series.