WEST ALLIS, Wis. — IndyCar points leader Helio Castroneves insisted Friday that his race-winning car at Texas did not have a performance advantage from an illegal part that led to a failed post-race inspection.

IndyCar this week fined Penske Racing $35,000 and docked Roger Penske 15 owner points because the underwing height on Castroneves' car was too low following Saturday night's win. Penske Racing put the car in a wind tunnel Monday and determined it had no advantage from the part and actually raced at a disadvantage because Castroneves had three pounds less downforce and one pound more drag than if the wing was correct.

Castroneves, who said he was "very shocked" the car failed inspection, was thankful the team took that step.

"Just to show that Team Penske, when people start making noise, did not have any intention to do what happened," Castroneves said at the Milwaukee Mile. "It was just a simple mistake. And with that mistake, they spent the money to put the car in the wind tunnel to prove that it didn't go to improve the performance. One pound of drag, believe it or not, it cost a lot, especially at Texas."

Castroneves said he is determined not to let the penalty overshadow last week's run, which was his first win of the season and first for a Penske driver. Castroneves led the final 132 laps in a car he doesn't believe was the class of the field last week.

"We had a winning car, but I don't think we had the fastest car, to be honest," Castroneves said. "I think we had a consistent car. Mistakes happen, and we shouldn't judge that because of a simple mistake. It was certainly very shocking because the team did an absolutely amazing job. I will not allow this scenario to outshine what we did because it made my car slower."

Castroneves also downplayed the importance of his win at Texas as a breakthrough for Penske Racing. IndyCar has had seven winners through the first eight races of the season, and until Castroneves' win, none of the victories was by drivers from heavyweights Penske or Chip Ganassi Racing.

He believed focus on the stat was sensationalism.

"You guys in the press obviously want to sell news and this is a way to sell news — 'Penske didn't win!'" he said. "But, you have got to say we've been competitive. I made a mistake in the first race of the season. It's circumstances. All the teams are improving. You have to say it is not about Team Penske or Team Ganassi — other teams step up their game.

"A big credit for the small teams. It shows that the series is very, very competitive. It gives an opportunity for a rookie to win races. That is why our series is one of the best."