Then you read stuff like this:
December 21, 2006 – A very restrictive, strongly enforced noise rule will be in effect at Yakima Speedway for all competitors in 2007.
All competitors, local classes, and touring series must meet a DBA reading of 98@ 75 feet. There will be no exceptions.
A maximum exhaust pipe size of 4 inches will be enforced.
All competitors will be tested. Any competitors found in violation of the noise rule will be returned to the pit area and be given only one more chance to quiet the car down. If the car does not meet the noise level the second time, the competitor will be disqualified from further competition that race day. No refund of entry fees or pit passes will be given.
Officials may request a competitor make a timed lap to determine the noise level of the car. The timed lap must be within reason of the competitors normal racing, timed laps.
IMPORTANT:
Any competitor that installs a properly mounted, untouched, 4 inch, Aero Exhaust muffler will not have to worry about meeting the sound limits. The Aero Exhaust muffler has been proven to quiet the cars down under the DB level in force at the facility. The Aero Exhaust muffler is a high quality, performance enhancing, unit that Yakima Speedway would like for all competitors to use. The installation of the Aero Exhaust muffler will ensure competitors that when they come to Yakima Speedway the noise issue will be handled.
To encourage racers to use the approved Aero Exhaust unit, Yakima Speedway will sell them at the reduced cost of $130.00 per unit. Both 4 inch and 3 1/2 inch models are available.
The strong enforcement of the noise rule is due to many factors. Leaving it up to the associations, competitors etc. has not worked. With Yakima Speedway being located in the city limits, it is in the racing communities best interest to police ourselves.
