DAYTONA BEACH, Fla. -- Joe Gibbs Racing has suspended two Nationwide Series crew chiefs for the remainder of the season in the wake of penalties handed down by NASCAR after rule violations were discovered by inspectors prior to post-race testing on the chassis dynamometer Aug. 16 at Michigan.

NASCAR announced that seven crew members -- including No. 18 crew chief Jason Ratcliff and No. 20 crew chief Dave Rogers -- have been placed on indefinite suspension.

In response, team owner Joe Gibbs said in a statement: "A poor decision was made by some key members of our organization, and 100 percent of the blame rests with us."

Gibbs also noted that JGR would adding its own penalties to the team members on top of NASCAR's sanctions.

"We had come to the conclusion that we would add to any NASCAR imposed penalties with the minimum being suspension for the remainder of the season for those involved, including our two Nationwide Series crew chiefs. There will also be an additional monetary fine beyond the amount announced by NASCAR earlier today, which will be the responsibility of those involved."

A JGR spokesman confirmed to NASCAR.COM that team has suspended the seven crew members for the remainder of the season.

Both the Nos. 18 and 20 cars were found to be in violation of:

• Section 12-4-A (actions detrimental to stock car racing); 8-9 (competitive analysis -- from time to time, NASCAR may determine, in the interest of competition, that it is necessary or appropriate to undertake an analysis of the performance capabilities of a car, car part, component or equipment. The Competitor shall take whatever steps are requested by NASCAR Officials for this purpose. NASCAR also has the right to seal or impound cars, car parts, components and/or equipment for this purpose);

• Section 12-4-Q (1): (car, car parts, components and/or equipment used that do not conform to NASCAR rules, detailed in Section 20A of the 2008 NASCAR Rule Book, or has not been approved by NASCAR prior to the event, or is not required for the normal functional operation of the race car, or has been altered to detract from or compromise its integrity or effectiveness, whether operational or not);

• Section 12-4-K: (when NASCAR Officials mandate inspection during the Event, if any car, car parts, components, and/or equipment which have been used in the Event are taken from the racing premises without permission of a NASCAR Official, or are tampered with by any member of the team or anyone associated with the team: Magnetic spacer attached under the gas pedal with the intent of compromising the chassis dynamometer test).

As a result, NASCAR issued the following penalties:

• Both of the drivers -- Joey Logano of the No. 18 and Tony Stewart of the No. 20 -- have been penalized with the loss of 150 championship driver points and placed on probation until Dec. 31. Joe Gibbs, owner of both of the cars, has likewise been penalized 150 championship owner points for each of those entries.

• Both crew chiefs -- Ratcliff and Rogers -- have been fined $50,000 and indefinitely suspended.

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Both JGR crew chiefs and five other team members were indefinitely suspended by NASCAR following an attempt to manipulate dyno results after the Nationwide Series race at Michigan. Did the penalties fit the crime?

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• From the No. 18 team, car chief Dorian Thorsen, engine tuner Michael Johnson, and crew member Toby Bigelow have been placed on indefinite suspension.

• From the No. 20 team, car chief Richard Bray and engine tuner Dan Bajek have been indefinitely suspended.

• In addition, the entire Nos. 18 and 20 Nationwide Series teams have been placed on NASCAR probation until Dec. 31.

"In our post-race inspection, our inspectors discovered some shims that were placed on the gas-pedal stop. They were magnets that were about a quarter-inch thick that prevented the accelerator from going 100 percent wide open," said Robin Pemberton, vice president of competition for NASCAR.

It is not unusual for NASCAR to test cars on the chassis dynamometer, which measures rear-wheel horsepower. Officials have administered this test several times during the season, and the Nos. 18 and 20 cars were only two of several that were tested following the race.

"In 17 years we have never had any representative of Joe Gibbs Racing knowingly act outside of NASCAR's rules, and that is something we consider essential to how we operate on a daily basis," Gibbs said. "What we have determined is that these individuals involved used extremely poor judgment in attempting to alter the results of NASCAR's dyno test following Saturday's Nationwide Series race in Michigan.

"Although in no way was anything done that might have altered the race outcome, these JGR employees attempted to circumvent the NASCAR rule book and that is unacceptable."

The JGR teams in question have dominated the series for much of the season, combining to win 14 of 25 races. The infractions come shortly after NASCAR announced rule changes for the Toyota engines used in the Nationwide Series last month. The guidelines were intended to cut 15 horsepower and level a playing field that fellow competitors had insisted was lopsided for much of the season because they believed the Toyota engines were producing more horsepower than other manufacturers.

"We take full responsibility and accept the penalties NASCAR has levied against us today," Gibbs said. "We are, however, disappointed that NASCAR chose to place our drivers on probation, as they had no knowledge or involvement of this incident."

• Related: JGR faces penalties after Nationwide post inspection