Rahal: Honda's IndyCar road course aero needs improving everywhere

Honda has struggled to match Chevy ever since the manufacturer-designed aero kits made their debut at the season-opener in St Petersburg.

Rahal ended the opening day of practice for this weekend's race on the IMS road course as the quickest of the Honda-powered runners, but he was still more than 0.4 seconds off the pace, and admitted that the gap will be difficult to breach.

"We've got a lot of work to do," Rahal said. "As you can see, it's half a second to the Chevys.

"I don't know where half a second is going to come from, but we're going to try awfully hard to try to find it.

"I think at this point we just have to find a little bit everywhere.

"The car is pretty hard to drive. It's pretty pitch sensitive. You find you're sideways more than you're pointed straight.

"If you're doing that [and] it's fast, that's okay. That's where we've been this year.

"It's not typically how I would have set up a racecar, but it's worked for us so far.

"I think the guys at Honda are working awfully hard at digging away to find more power, a little less drag. We'll have to see how it plays out.

"At this point we have just got to do what we have to do to try to make the thing go a little bit quicker.

"Us as a team, we've never had it in a wind tunnel or anything like that. We're just kind of having to keep it pretty simple and do what we need to do to help improve the car."

Honda leads the manufacturers' championship despite having only scored one win to Chevy's three, as the result of Chevrolet incurring a raft of points penalties for making repairs before its engines reached their 2500 minimum mileage.

Those penalties did not apply to the drivers' championship however, where Chevrolet's early dominance is reflected in the fact that there are no Honda-powered drivers in the top five, and just two in the top 10.

Following this weekend's race, the teams will switch to the speedway-spec kits in preparation for the Indianapolis 500.