If you bleed GM performance like we do, you were blown away by the 2014 Z/28’s introduction. When the new Z took the stage at this year’s New York International Auto Show, it joined an already stellar Camaro lineup that includes the LS, SS, 1LE, and ZL1. With the race-ready Z/28 slated to roll off the Oshawa line in early 2014, Chevrolet will dominate the Mustang at all trim levels, on all roads—and on all tracks.
You may have noticed that the “slash” is back. “Z/28” is the General’s latest alphanumeric riddle (it applies to the 2014 model…and the 1960s one…but not the slash-less 1970s-2000s Z28s…got that?). Z/28 joins ZR-1 and ZR1, LS-6 and LS6, and many other vehicle and engine names that we enthusiasts (and GM, for that matter) can’t seem to keep straight. But as Z/28 hearkens back to those heady days of high-revving, sharp-handling 1967 Camaros on SCCA circuits, this track warrior is clearly worthy of those Z/28 badges.
How worthy? The 2014 Z/28 is powered by a high-revving, dry-sump LS7 with an integral liquid-to-liquid engine oil cooling system. It wears massive carbon-ceramic brakes, 305mm gumballs at all four corners, an aero package, and a precision-tuned suspension with high-tech race dampers.
The Z/28 went through an “intensive lightweighting program”: In addition to weight removal from unsprung components, the interior sound deadening and trunk carpeting was tossed, the rear window got thinner (3.2mm) glass, a smaller battery was used, and the tire inflator kit was tossed (except for RI and NH-bound Zs). Lighter rear seats and no trunk pass-through save weight, too. Engineers wanted to remove the entire audio system, but had to keep it for the seatbelt warning chime—so it has a grand total of one speaker. Air conditioning is an option, a manual trans is standard. Even the manual-adjustment Recaro buckets are light. Combined, the Z/28 is 100 pounds lighter than an SS, and 300 pounds lighter than a ZL1.
The hard numbers are befitting of a true race car: 500-plus horsepower/470-plus lb-ft of torque, which could translate into high-3-second 0-60 sprints, and low 12s in the quarter. 1.5 g in deceleration, 1.05 g in lateral acceleration. And while “downforce at track speeds” is all of the aero info that GM is releasing at this point, you can count on significant aerodynamic enhancements, as well.
We were just as hot and bothered by those parts and specs as you were, and wanted to learn more about Z/28’s backstory. So we connected with Darren Bohne, the Assistant Program Engineering Manager for Z/28 and all-around good guy, who told us how the most extreme Camaro ever built was born.
GM High-Tech Performance: We heard that your team made nearly 200 changes to the Z/28 to improve its track performance. What was the main focus of those changes?
Darren Bohne: The Z/28’s focus on lap time is a three-pronged approach. Go, stop, and turn. The driveline, combined with the brakes/wheels/tires, is able to make this car the fastest track Camaro ever. When you look at the parts list that makes up the unsprung mass, we touched every one of the part numbers, except for things like lug nuts. And we even asked the question: What can we do to make the lug nuts lighter?
GMHTP: Compared to a 2014 Camaro SS, how does Z/28’s suspension and chassis differ?
DB: When we started engineering the Z/28 we looked at every part of the chassis; the biggest changes were going after unsprung mass in the tires, wheels, and brakes.
In addition to their individual performance benefit, the smaller tire/wheel package allowed us to bring the car’s center of gravity down 33mm compared to an SS. By using Multimatic’s DSSV (Dynamic Suspensions Spool Valve) Dampers with increased spring rates, we’ve developed a very track-focused package that delivers on the promise of being the most track-capable Camaro ever.
GMHTP: Can you provide some insight on how the Multimatic spool-valve dampers were chosen for the Z/28?
DB: On the ZL1, we have MR [dampers] for their great ability on both the street and the track. But with the specific focus of the Z/28, we chose to go with a passive damper that was tuned for one thing—the fastest lap times. Multimatic’s DSSV dampers fit the bill, and they also have mass-related benefits.
GMHTP: What were your team’s expectations for the DSSV dampers, and how were they dialed in at the track?
DB: We knew that Multimatic’s DSSV dampers had to give us very precise wheel control throughout the operating range, as well as be stable over long track sessions.
GM and Multimatic engineers spent time together using computer modeling and 4-post testing to determine the correct valve before ever going to the track. Instead of trying to flow fluid through a standard shim, the DSSV dampers allow us to control fluid flow through a calculated valve opening that can be adjusted for piston speed. This gives us very tight control over the dampers.
From there, the team headed to the track to make any necessary fine-tuning adjustments to get the most out of the car. The DSSV dampers gave us independent control over the low speed and high speed operating range. In addition, they’re not susceptible to significant changes due to temperature, so you have consistent handling, lap after lap.
GMHTP: Speaking of trick race-ready parts: Can you describe how the 15.5-inch front/15.3-inch rear Brembo carbon-ceramic brakes (CCMs) affect the overall feel of the Z/28? What was it like track testing with them?
DB: The best CCM brakes feedback came from our drivers after their first few test sessions. With their output capability paired up with the Trofeo R tires, some of our best drivers were taking the Z/28 so much deeper into the corners than they thought possible. The first time into the corner, the guys felt pretty good braking between the 2 and 1 markers. By the end of the session, they were coming back in and saying, “Did you know you can wait until .75 to brake?!”