Honda stumped by deficit to Chevrolet in Phoenix IndyCar qualifying

The manufacturer was afforded off-season scope to change its aero kit, but on the year's first oval failed to get a driver into the top 10 in a Chevrolet-dominated qualifying session.

Honda teams had 11 of the last 12 spots on the grid with the only Chevrolet driver out of the top 10 Sebastien Bourdais, who qualified 15th.

Chevrolet repeated the numbers in the final practice session by sweeping the top 10, with Bourdais again the only driver to miss out, in 14th.

When asked if Chevrolet had an advantage, Tony Kanaan, who qualified second, said: "I think you can look at the grid.

"That answers you right away. Look at the top 10 there and you tell me what you think."

Consultant Gil de Ferran admitted Honda did not know why its short-oval aero kit was so far off the pace in qualifying, or whether it would be any different in the 250-lap race.

"We observed that the opposition has an edge in qualifying trim," he said.

"We need to analyse and understand why and see what happens in the race.

"Maybe the same thing will happen in the race, and maybe race conditions will be a little different.

"I don't know what Saturday will look like but obviously [on Friday] we have to analyse and understand because this is not how we want the grid to look like.

"But I cannot tell you until then what is causing what.

"We need to understand the reason and do proper engineering analysis and do a lot of timing data from the cars and work."

Marco Andretti will lead the Honda drivers away in the race, in 11th.