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Restrictor plates cut New Hampshire speeds

NASCAR will use horsepower-reducing engine restrictor plates for next weekend's New Hampshire Winston Cup round following two fatal accidents at the track this season

Adam Petty was killed after hitting the Turn Three wall in practice for a Busch Series race in May, with former Winston Cup Rookie of the Year Kenny Irwin dying after a near-identical crash in Winston Cup practice in July.

The New Hampshire banking is among the least steep on the Winston Cup schedule. The entry to Turn Three is the fastest part of the 1.058-mile oval and cars suffering a stuck throttle - which was initially suspected in both accidents - are unable to scrub off significant speed on the banking before hitting the wall. Energy-absorbing foam on the wall was initially considered, but rejected in favour of a reduction in speed.

The one-inch diameter plates, which are fitted to the carburettor air inlet, will reduce engine power from 750bhp to under 500. NASCAR technical director Gary Nelson estimates that top speeds at New Hampshire will be reduced by 10mph, to 135mph. Smaller diameter (7/8 inch) plates are already used at Daytona and Talladega, but this is the first time NASCAR has mandated their use at a track other than a superspeedway.

"It would take magic to get the speed back when you take away that much horsepower," said Nelson, "so we are very confident that the speeds will be reduced at New Hampshire at the critical stages on the racetrack when the cars are at top speed."

Nelson countered fears that the restrictor plate would mean the whole of the lap would be run on full throttle - a situation that has led to several multi-car accidents at the superspeedways, due to the field running in a single pack.

The Winston Cup cars will also run compulsory brake-warming laps behind a safety car before each practice session at New Hampshire.

NASCAR has already introduced steering wheel-mounted kill switches in the wake of the accidents and will continue to investigate other safety measures, including a Jack Roush-designed automatic engine kill switch that can detect a sticking throttle. Roush driver Jeff Burton has already run the system in this weekend's Busch Series race at Richmond.

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