A boost is not always a plus in IndyCar racing

INDYCAR officially announced on Thursday that boost levels for Fast Friday and both Pole Day and Bump Day qualifying will rise to 140 kPa from the current 130 kPa maximum level.

But what exactly does that mean on the track?

As a rule, a ten kPa increase in turbocharger boost results in an additional 30-40 horsepower delivered to the wheels, which at the 2.5 mile oval at Indianapolis Motor Speedway should translate to lap speeds an additional 3-4 mph faster than those recorded so far this month.

For example, the fastest speed recorded over Thursday's six-hour practice session was that of Carlos Munoz at approximately 225 mph. On Friday it's quite likely that, all things being equal, Munoz could and should clock a speed of 229 mph. All things being equal, of course, means that if conditions on Fast Friday are more favorable (cool weather, light or no wind, a clear track and a tow from another fast car) we might even see several 230-plus mph laps at the Speedway.

Ironically the IndyCar series Dallara produces its fastest speeds at Indy with the least boost used at any track on the schedule. Boost levels of road and street courses are routinely set at 150 kPa, with "Push to Pass" levels of boost extended to 160 kPa.

You might ask why the series doesn't raise the boost for Indianapolis, just for Fast Friday and qualifying, in order to challenge the long-standing four-lap track record set by Arie Luyendyk in 1996 at just shy of 237 mph, and one sizzling lap at nearly 237.5 mph.

The answer is: engine reliability.

More boost means more wear on the engine, specifically, not to mention the other drive train components under the IndyCar bodywork.

Drivers are eager to get more ponies under their right foot and most acknowledge that the increase in power at Indy over the next three days is a welcome change.

"The cars are so close (in terms of performance)," said Andretti Autosports James Hinchcliffe, "that even a change in ambient air temperature can make a difference in who gets into the top nine cars and shoots it out for the pole. You can plane it (the car) out, and trim it out to go faster and all the rest, but the only way you can say for good that the car will go faster is with more power."

In 2012 Chevy benefitted the most from the hike in boost levels at the Speedway. After being routinely pummeled by Honda in the season's earlier rounds, the bow-tie engine came to the fore in the sessions leading up to last year's 500 when the boost limit was raised to the same levels as will be allowed this weekend.

Despite the competitive success afforded by the change, Chevy engine development chief Peter Bennett says that keeping the boost level at a higher level long-term and running faster aren't the full scope of the manufacturer's goals. “We continue to develop all the time and our goal is three-fold: more performance, fuel economy and durability,” he said. “The 2012 season gave us confidence in the twin-turbo engine. However as we increase performance and push the engine harder, we will undoubtedly uncover other durability concerns.”

One should keep in mind that engine changes in IndyCar are mandated at 2000 mile intervals, and not sooner; which forces a constraint to maintain durability on the engine suppliers. It also helps keep costs in line with IndyCar's desired expense profile for the series.

The result is a fascinating game of engine management cat and mouse as teams, drivers and manufacturers look for that special combination of speed, mileage and durability that will put them in line for a taste of milk on Memorial Day.