New look for race cars at Honda Indy
If you’re attending the Honda Indy Toronto race this weekend, and aren’t a regular follower of the Verizon IndyCar Series circuit, you may be in for a shock. The cars look very different than they did last year.
They look much different than those you might have seen on the Indy 500 telecast, too. And different even from those that started the season on street and road courses.
All those differences are the result of what IndyCar calls “aero kits,” available for use this season for the first time and evolving almost race-by-race.
Beneath their new skins and wings, the cars are essentially the same as they have been since they were introduced in 2012 — all Dallara DW12 chassis with either Chevrolet or Honda engines.
For the first three years of the cars’ use, they were all restricted to the same bodywork and wings, as supplied by Dallara per specifications dictated by IndyCar, the series’ sanctioning body.
To increase the competitive variables and provide for more visual differentiation for fans, the so-called aero kits were introduced for the 2015 season. That expansion of the regulations allows teams to vary their bodywork and wings, within tight limits, to improve their aerodynamic efficiency.
Each of the engine manufacturers developed their own aero kits, for use on cars powered by their en- gines.
They didn’t have carte blanche on what they could do, however. Twelve different “volume boxes” were defined on the cars, within which aerodynamic changes could be made. The rest of the cars had to be left unchanged.
They each had two different aero kits to develop — one for use on superspeedways such as Indianapolis, where speeds are consistently above 200 mph (322 km/h), and one for street and road courses such as Toronto, where speeds are lower and vary dramatically on each lap.
In either case their broad objectives were the same: to maximize downforce and minimize drag — two goals that are typically at odds with each other.
For speedway use, minimizing drag takes precedence, which is why the cars you may have seen on TV in the Indy 500, or last weekend in Texas, seemed to have minuscule rear wings.
For Toronto and other street or road circuits, however, downforce is king. It’s essential to maximize traction for accelerating out of corners as well as maintaining grip through them. So big wings, at both ends, are key components in the aero kits for those tracks.
Within those broad objectives, the two manufacturers’ responses to the challenges were quite different in appearance. Both succeeded in significantly enhancing downforce, however. Too much so, in fact.
When they submitted their initial test data to IndyCar for approval of their designs, the sanctioning body became concerned that the resultant loads might exceed the design limits of the Dallara chassis.
Consequently, additional specification changes were made in underbody strakes and side walls to ensure that forces stayed within safe limits. IndyCar set a maximum downforce target of no more than 25 per cent above that achieved with the basic Dallara aero kit.
At the opening race of the season in St. Petersburg, Fla., front wings on both manufacturers’ cars proved highly susceptible to even light contact, littering the track with carbon fibre.
Since then, changes have been mandated for both manufacturers’ aero kits to simplify them and remove the most susceptible or aggressive elements, such as freestanding winglets on the Chevrolets and vertical planes on the Hondas’ front wing-ends.
Those changes were in effect for the last road-course race, in Detroit, and are expected to remain unchanged for Toronto.
Which is not to suggest that the challenge here will be decreased in any way. It’s always a tough track for which to set up and the adoption of aero kits will probably make it tougher than ever.
Its many corners and changing surfaces put traction at a premium, which means lots of downforce is required. But high top speeds are essential for lap times and passing at the end of the long Lake Shore Blvd. straight, so low drag is also on the want list.
How the engineers balance those two conflicting requirements will weigh heavily on how their drivers perform.
To that end, those engineers now have many more decisions to make than ever before, for the aero kits bring with them many more possible adjustments — even the possibility of adding or subtracting various aerodynamic elements.
Lots more opportunity to improve things, or to make them worse. Assuming they get them right, expect a new track record. Gerry Malloy is a regular columnist for Toronto Star Wheels. His Tech Talk appears every two weeks. For more automotive news, go to thestar.com/ autos. To reach Wheels Editor Norris McDonald: