Art St. Cyr, president of Honda Performance Development, explains how HPD has taken advantage of IndyCar Rule 9.3 to make gains on the opposition this season.
Honda Performance Development (HPD) has had a lot on its plate since the end of the 2015 Verizon IndyCar Series season. Even before the previous campaign was complete, HPD had been proactive in requesting changes to their aero kit, which had been deficient to the Chevrolet kit.
That didn’t stop Honda from winning races, but it certainly proved to be a problem in qualifying, where Chevrolet captured all 16 poles in 2015. In fact, Chevy powered cars locked out the front row for every race.
HPD went to IndyCar’s leaders and requested added changes to the three permitted on aero kits at the start of each season through rule 9.2. The manufacturer invoked rule 9.3, asking for remedies to remove the car’s relevant aero deficiencies.
Art St. Cyr, president of HPD explained: “Part of the issue we had last year was a recognized aerodynamic deficiency, in both superspeedway and road course trim. Rule 9.3 stated it allows us to catch up to where the competition was.
“Based on some exhaustive testing in the wind tunnels, with both our kit and the competitor’s kit, IndyCar deemed there was a measurable difference in performance between our kit and the competitor’s kit on road courses, but in the superspeedway spec they deemed us not to have quite the disadvantage, although the results of the Indy 500 might say something different.”
In that race Graham Rahal, fifth, was the highest-finishing Honda driver; he went on to take fourth in the championship chase, winning two races in the process.
St. Cyr continued: “Once we [were allowed] to do the 9.3, then we still had Rule 9.2, which are the open area boxes to develop, so both Honda and the other side are working with those, as well. So the differences that you’ll see on the track are really mainly due to those 9.2 areas.”
Cars were "hard to drive"
Essentially, once allowed to open their development on the aero kit, which had originally been designed in conjunction with Wirth Research, who place great emphasis on computerized simulation correlating to computational fluid dynamics (CFD), HPD addressed difficulties experienced by teams and drivers.
“Our cars were a little bit hard to drive, depending on the setup,” said St. Cyr. “You could go into the corner with an understeer, be neutral in mid-corner and oversteer coming out of the corner or some combination of the bunch. It made it really hard for the teams to setup the car the way that they wanted to set it up.
“If you could get the setup correct, the kit could be really fast. However that forced the teams to adjust to the way the aero kit drove and not the other way around.
“One of our main goals with the aero kit for 2016 was to widen the operational window, to make it simpler and much easier to drive.”
Asked about the manner of deficiency, of course St. Cyr was coy, stating that there wasn’t a specific target number to increase downforce and decrease drag on the Dallara DW12.
“It’s a ‘lift over drag’ efficiency number that was the basis” for the changes that Honda sought and received, utilizing both the catch-up rule (9.3) and the standard 9.2 adaptations from 2015 to this year.
Engine specs also tweaked
In addition to aero changes from last year to this, both Honda and Chevrolet have been able to make adjustments to their engine specifications - and are able to adjust some items in-season from their first-spec engine to their fourth-spec engine. Only four engines are permitted for the full, 16-race season and for testing. Engine homologation rules allow for specific changes for each year.
Said St. Cyr: “This year a lot of the combustion chamber areas - intake ports, camshaft, cam timing - were open for adjustment. We did make some pretty significant jumps in engine power.
Last year, especially in the low-speed corners, we were actually pretty fast so we would say we were fairly competitive on the engine side. This year we did make a pretty good jump in both torque and horsepower on our engine to hopefully be even more competitive this year.”
In 2015 HPD was forced to change some engines earlier than the mandated 2,500 miles, so the manufacturer was striving to increase the longevity, reliability and strength of its power plants this year.
“There are changes that we made to the first spec engine that’s in the car right now that is an improvement over last year,” said St. Cyr but there are some other hardware points that have some incremental changes, but a big chunk of it is already on the cars right now.
“There are some items that are open: you can always change pistons, you can always change valves, you can do those types of things.
“So any time you change the spec of the engine, you can change those parts, so there’s always some opportunity for some small improvements as you go from the first engine to the second to the third to the fourth engine. Right now, all cars have the first spec at the start of the season.
“Like I said, our aero kit philosophy was to make the window wider so that teams could actually drive the cars harder, but a lot of the speed difference that you’ll see will be due to increases in engine performance.”