Timeline:
Streets of Detroit /
Transport America Redux /
The Land of Milk and Honey
Model Name: BMW i8 GTO
Manufacturer:
- BMW Motorsport (engine, drivetrain)
- Siemens Drive Technologies (hybrid system)
- Crawford Composites (chassis central section)
- Coyote Racing Cars (chassis ends, bodywork)
Model Type: Silhouette Racing Car
Model Year: 2012-2018
Origin
:
- Munich, Bavaria, Germany (engine, drivetrain, hybrid system)
- Littleton, Colorado, United States of America (chassis center section)
- Calverton, New York, United States of America (bodywork, chassis assembly)
Engine:
- BMW B58SR10 3000cc twin-turbocharged inline-six
- Siemens 2SCR kinetic energy recovery system (2 Siemens SR70K motor-generator units, Altairnano Technologies parallel lithium-ion battery/ultracapacitor energy storage)
Power: 627 hp @ 8750 rpm (gas engine), 794 hp @ 7000 rpm (with KERS boost)
Torque: 410 ft-lbs @ 7500 rpm (gas engine), 840 ft-lbs @ 4500 rpm (with KERS boost)
Drivetrain: Mid-engined, all-wheel-drive (KERS system operates on front wheels, gas engine on the back)
Transmission: Aisin Seiki SR804B eight-speed semi-automatic transmission
Weight: 1,175 kg (2,593 lbs) minimum
0-100 km/h: 3.7 seconds
Top Speed: 210+ mph (est.) 194.65 mph (qualifications, 2012 24 Hours of Daytona)
MSRP: $525,000 (limited)
Number Produced: 27
The dreams of a single set of Grand Touring car rulebooks went back right to the very beginnings of the grand touring car era of sports car racing in the early to mid-1990s, and through multiple evolutions of the rulebook, the differences of opinion between the world's various sports car organizing bodies made sure that commonalities, where they were found, were fleeting and rare....until the perfection of the GT3 rulebook by Stephane Ratel and his SRO organization in the late 2000s, followed by the evolution into something more of the GTE class cars at Le Mans in the early 2010s. For IMSA, however, things got different - the economic downturn of 2007-2008 and the financial problems that both rattled Detroit and shook the entire world's economy during that time period, when combined with the creation of the World Endurance Championship in 2008, caused a massive and precipitous drop-off in the field size for the IMSA American Le Mans Series' top classes. Faced with this but blessed with the series' top-notch GT categories, the introduction of GT3 cars in North America and involvement with the Japan Auto Federation and Germany's ITR over the Class One rulebook, focused its efforts on the creation of a single grand touring car rulebook for themselves, but quickly found out it was liked by others around the world.
The result in late 2010 was the WSC/LMP era which had begun in 1994 ended with the introduction of the GTO category, while the existing ACO GT2 class became GTE, the GT3 category came into its own as GTS and the monster tube-framed Trans-Am cars entered the series as AAGT. The introduction of the cars, which combined cost-effective rules with both high-tech features and a surprising amount of technical flexibility, was an instant hit when IMSA began operations with the rulebook in 2012, and was surprised to find the Super GT series in Japan doing the same at the same time, while the DTM series soon had an agreement with the existing ADAC GT Masters series for combined multi-class races on multiple occasions. The agreements allowed for the Super GT's combination of its 'mother chassis' GT300 cars to be integrated with the FIA GT3 cars, while the GTE cars swelled rapidly in both power and aggression, with Ferrari replacing the mid-engined 458 Italia with the awesome LaFerrari GTE and Porsche replacing the 911 GT3 with the 918 GTE for the category, while the competitors from Chevrolet, Ford, Dodge, Aston Martin, Lexus and BMW soon upped the pace of existing cars. It added up to new cars for most of the field in 2012, and it showed in IMSA's popularity, which thanks to the new, high-tech cars, multiple fan-engagement projects and a wide marketing program during 2011 grew quite substantially in 2012 and continued on an upward trajectory.
Of the GTO cars, the BMW i8, Mazda Furai, Lotus Esprit and Acura NSX-R went for mid-engined layouts, the i8 and NSX taking the 75 kg weight penalty for hybrid cars in return for a considerable amount of boost power, while the Ford Mustang, Toyota Supra, Mercedes-Benz C63 AMG, Audi RS5 and Nissan GT-R Class One chassis went with front-engined designs and only the Supra using hybrid power. As per the Class One rules, all cars had a spec carbon fiber center tub with a ultra-high-strength steel roll cage and carbon fiber-reinforced steel tube-frame structures on either end of the chassis, the Class One tub design made specifically to allow both mid-engined and front-engined cars to compete using it. Only three makers - one each in Germany, America and Japan - were contracted to make the Class One center, but anybody could make an outside chassis for it if they wished, and more than a few companies and teams did, but the cost control rules - complete, ready-to-race chassis had to be able to be bought from any manufacturer at a maximum cost of $450,000, including everything except an engine and an optional KERS system - did make sure as few people were priced out as possible. Engine rules were more than a little wide-open - production-based engines were allowed up to 6400cc naturally aspirated, 3800cc using forced induction and up to 5500cc when running on diesel fuel, while naturally-aspirated racing engines were allowed up to 4000cc when naturally-aspirated and up to 2200cc when using forced induction.
The i8 GTO was built using a Siemens-built energy recovery system similar to that which saw use in Formula One cars in the mid-2000s, using two geared motor-generator units and a battery-ultracapacitor bank to recover power and release it as a support to the gas engine. The car was powered by BMW's then-brand new S58 inline-six engine, which used twin turbochargers and fluid-to-air intercoolers for power, which soon gained a reputation for being both fast-revving and powerful at medium to high RPM ranges while weaker at lower speeds, a problem largely negated by the use of the KERS system in the i8 GTO. A transversely-mounted eight-speed semiautomatic gearbox and a mechanical limited-slip differential put the power to the wheels. The four different gearbox makers of the Class One cars - Aisin Seiki, Hewland, BorgWarner and Westland - all made eight-speed gearboxes for the Class One cars, with the taller-geared Westland and BorgWarner units seeing more use on the bigger-engined Mustang, C63 AMG and RS5 made up for the taller gears with torque, while a special short-gear Aisin Seiki unit was used in the Wankel Rotary-engined Furai.
Aerodynamically, the cars were designed wild and stayed that way. The rules allowed 'simple' active aerodynamics such as drag reduction flaps, rear wings and air brakes, and all cars used them. Tires were limited in grip by the requirement that they could only be changed on every other pit stop and all tires and all compounds had to be available to all teams who sought them, conditions that didn't stop Michelin, Continental, Goodyear, Bridgestone and Yokohama from competing. The cars used mostly-flat underfloors but with excavators, splitters and diffusers as well as spec-sized hanging wings. The chassis were all designed tough and durable, and while the crazy aero may well otherwise dissuade people from playing tough, competition in all three Class One series soon showed how untrue this was.