Peak Performance: Part 2—The Vehicles
by Chris Leone // Website // Twitter
Images via Acura
As times continue to plunge at Pikes Peak year after year, one manufacturer found itself rewriting the history books in 2018. Join us at Rally-America.com and iRally every day this week as we take a look back at Acura's 2018 Pikes Peak International Hill Climb program!
In the end, Acura would send four race vehicles to Colorado: Peter Cunningham’s Open class TLX GT, Nick Robinson’s Exhibition class TLX A-spec, James Robinson’s Time Attack 1 class NSX, and Jordan Guitar’s Exhibition class RDX, along with many other pieces of equipment and the RDX A-spec pace car driven by Olympic figure skating bronze medalist Chris Knierim. Each featured a number of different upgrades to help it get up the mountain faster, but some were more stock than one might expect.
“The NSX that I got to drive this year has been an incremental growth from the base car, and in fact it’s still in a lot of ways a mass production NSX,” admits James Robinson. “Basically, this year we were fiddling with new aerodynamics on the car, and also working on the powertrain calibration on the car.”
Interestingly enough, despite sharing a nameplate, the two TLXs may have been the most different of the bunch—though that may be no surprise when you consider that Cunningham’s car, prepared by his RealTime Racing group, was intended for a different purpose entirely before being converted to hill climb spec.
“I think I heard (Peter) say that his car, the TLX GT, and the road car, which is what mine was based off, I think they share an A-pillar,” Nick Robinson says. “Everything else is completely bespoke on PD’s car. But the purpose of the TLX GT was to race in the Pirelli World Challenge as kind of a silhouette car, to get the Acura name and the TLX shape out there and competing.
“What we do at the R&D team is, we kind of have a decree from our executives to race what we build. So all of the cars that we’re driving or competing with, we actually developed in Ohio, including the TLX. So the car that I drove was, I think, a late pre-production car, meaning it was a saleable unit before mass production. Honestly, a shadetree mechanic could replicate that car from a chassis standpoint pretty easily.”
It’s finding power at altitude that always proves the biggest challenge at Pikes Peak, and so most of the modifications to the vehicles were made under the hood.
“We used the exact same engine and turbos that had just run the year before,” Cunningham notes. “But because of further research by the HPD folks, they determined that our boost settings, or more specifically our turbo speed settings from 2017, were conservative. These turbos are designed to race at sea level, or even 4,400 feet above sea level in the case of Utah, so in 2017, we could only rev the turbos to a certain speed—which limited the amount of power that we could generate.
“At 9,000 feet, you can only make so much boost at that top RPM on the turbos, and then as you ascend, we actually had to turn the boost down twice during the run. Last year, we probably had 500 horsepower at the start line; then, at Glen Cove we had to turn it down to 450, and at Devil’s Playground, we had to turn it down to 400, in effect. Whenever the turbo alarm went off, we turned a mechanical switch to turn down the boost ask. This year was the same deal, only we started at 550, so we definitely had at least 50 more horsepower this year than we did last year.”
“This year, we changed the turbochargers from the mass production version to a larger unit to help us compensate for the altitude there, which is very extreme,” says James. “The start line is almost at 10,000 feet, so you’re already at a pretty distinct disadvantage. We’re trying to incrementally bump up to the limit of the powertrain to find the limit of the NSX street car.”
“James’s day job is in the engine development side of R&D, so he and some of his friends built (the TLX A-spec) engine actually a few years ago,” adds Nick. “He used the long block of that engine in the first-generation NSX that he competed with at Pikes Peak for several years. We recycled that engine, freshened it up, and used a different single turbo modification on it. Previously, it was a twin turbo in the NSX. So that part of it is probably a little bit more complicated, and maybe the shadetree mechanic would have a little more trouble replicating that part of the car.”
As if all that wasn’t enough, there was still one more advantage for Cunningham in the Open class: tires.
“This year, the rules changed for the Open class,” he explains. “In all previous years, the Open class had a requirement of running a DOT tire, so last year we ran a DOT tire and they worked very well. But this year, we were on some pretty nice Pirelli slicks, which didn’t hurt us! The DOT tires were great, but the Pirellis, being a race tire, certainly provided more performance.”