Note: there are some links within this post. They lead to posts from other threads that contribute to this vehicle’s overall lore.
Made in collaboration with @kookie
Blast from the Past
Zacspeed Racing partook in Group 5 before the silhouette days. Prior to 1968, Zacspeed ran 875s in the Group 6 Prototype-Sports Cars category. Come 1968, however, the FIA restricted Group 6 cars’ engines to three liters in displacement. With the Silver-York 427 four whole liters over this restriction, the 875s were rendered obsolete, meaning the team needed to switch gears.
Group 5 attracted Zacspeed’s attention because starting from 1969, minimum production was reduced from 50 to 25 cars. Since the team rebuilt its race cars with a new chassis every race or two, this gave them the idea to build a whole new car to race in this series. The end result was the Zacspeed 408, which ran 12-cylinder engines hovering around the class’s maxiumum displacement - five liters.
1972 arrived with a bevy of changes, including applying the Group 5 classification to the Group 6 category. Engine sizes were now reduced to three liters, banishing the 408 to Group 7 (better known as Can-Am). In its place came the 248, a 12-cylinder car free from the production restrictions the previous iteration of Group 5 utilized.
With 1976 on the horizon, Group 5 was revamped yet again. No longer could prototypes run in this category - competitors needed to modify production-based vehicles homologated in Groups 1 through 4. Zacspeed could not just throw a 12-cylinder in a light frame and get away with it anymore - they needed to bend one of their few production cars, the Zacspeed ONE, into a race-ready form.
1982 Zacspeed ONE Turbotarga
This would not be an easy task. The ONE did its own thing in more production-based classes, such as the ONE GTO finishing second at the 1970 24 Hours of Nürburgring. One of the perks to this program was how its new body tested a wedge-shaped front end with the lights implemented in the front. With improved aerodynamics and favorable owner responses, headlights on the bottom were here to stay.
The next key innovation came from the aforementioned 408. That car was banished to Can-Am, but while there, its 12-cylinder engine grew a few tenths of a liter larger and got hooked up to two turbochargers. This experiment, the 408/7B “Turbohammer,” did more than spit flames and hiss. It proved turbocharging’s viability in motorsport. The Turbohammer program ran from 1972 to 1973, and its findings were put into practice with the 1975 Zacspeed ONE Turbo.
Presented here is a 1982 example for this car. The Turbotarga is what happens when the fanbase prefers their near-death experiences without a top. Inside is the same 3214cc twin-turbocharged flat-six as the racing variants, but the wick is turned down to a reasonable 313 HP. It comes with plenty of turbo lag and is crammed behind the rear axle, which mix to complete a 0-62 MPH sprint in 3.8 seconds.
Despite the more radical bodywork and open top, it weighs it at just over 950kg. Part of this is due to its monocoque chassis and aluminum body, but it is also due to not having much in the first place. Later models, such as the 1989 Turbotarga, came with power steering and ABS. This does not. Add the fact it has a five-speed manual transmission “as God intended,” and it becomes clear why purists flock to this model even if they may not extract the maximum from its package.
Of course, to sell on Monday…
1982 Zacspeed ONE 5 #43 "Arctic Hare"
…You must first win on Sunday.
The ONE 5 was built from the ground up to fight. Grip and power were the two factors Zacspeed Racing focused on, especially considering how much weight was stuck in the rear. The bodykits applied to this car grew wide and wild, keeping the lights toward the bottom of the bumper and the wing as large as possible. Restrictions on the flat-six got loosened, and with more boost came almost double the power when it first appeared in 1976. By 1978, some versions made almost 650 HP, and these numbers only climbed as boost increased.
ONE 5s, such as the #38 car called “Peregrine”, rapidly spread across teams as a solid option for seizing high positions. As Zacspeed shifted focus toward other projects in 1979, customer teams developed their own ONE 5 specials, with some exceeding the factory cars on pure performance. Zacspeed Racing caught wind of this one-upmanship, and despite its shift in focus, it set out to build the ultimate ONE 5.
Grip was provided by the same 380-section rear slicks as some other ONE 5s. Turbocharging was advanced further to run an immense 840 HP. There was one new trick up the sleeve, however: ground effect. Ground effect primarily appeared in Formula One at the time; Zacspeed Racing started using it in 1979 with the FZ79. Aerodynamicists from the F1 team noticed that with the ONE’s monocoque chassis, it was possible to implement ground effect tunnels. From there, it was just moving components here and there around to grant clean airflow through them. On top of greater cornering, already aided by a curb weight of 1025kg, ground effect generates less drag, letting the Arctic Hare punch through 340 km/h. The Arctic Hare is the only ONE 5 sporting ground effect.
Concealing this potent package and one transmission mounted upside-down for lower ride height was an ever more extreme fiberglass bodykit. Off visuals alone, the car’s evolution into a prototype not unlike its predecessors was crystal clear. It sounds unfortunate, then, for it to be developed in Group 5’s twilight. Group 5 was shut down in favor of Group B from 1983, the same year, coincidentally, that F1 banned ground effect. That did not stop the Arctic Hare and its ONE 5 brethren from flocking to IMSA GTX and JSPC, where their kind was still accepted. The Arctic Hare in particular did quite well in IMSA even with the rise of purpose-built, ground-effect GTP cars as the Arctic Hair itself was already in essence a GTP car. Its drivers were John Paul Newman and Derek Bellof.
Arctic Hare remains the most extreme interpretation of the ONE 5. It borrowed experience from Zacspeed Racing’s Formula One team to develop aerodynamics to a new level. In return, the ONE 5’s numerous lessons on turbocharging were key to developing the engines Zacspeed relied on throughout the turbo era.
Wabbit Season
