Tucked away under the lights at this year's Tokyo Auto Salon in January was a very interesting prototype. Looking like something out of a German DTM series, the Lexus IS Racing Concept was on display next to the new IS-F. The specks of information from the guys at Toyota left the crowds perplexed but equally amazed at this mean-looking interpretation of a possible future touring car. Toyota's move was primarily done to get people talking, and that they sure did. All sorts of rumors were started, but it wasn't until a few weeks later that confirmation of a Super GT race car came in. Most assumed it was the car they saw at the Auto Salon, but in fact a private team built the GT300 class contender from the ground up. Behold the mid-engine, Green Tec Kumho IS350.
Wanting to find out more about this outstanding-looking car, we met up with the guys from Team Takeuchi during a closed test run at Fuji Speedway. Built by Shift, this Lexus IS350 shares very little with its road-going counterpart. First off, Super GT regulations allow a certain amount of modifications to be made to the chassis suspension layout, and engine type and position. So when we walked into the pits, we almost didn't recognize what we were looking at. The mechanics were swarming around a semi-deconstructed car with half of its bodywork gone to allow access to both the engine and suspension components.
Super GT allows race teams that compete in the GT300 class no restrictions in engine position, orientation, and type of engine used, as long as it's a production motor made by the manufacturer. On top of this, as long as the center part of the base shell isn't modified, teams are allowed to go crazy on chassis modifications. So it's not hard to understand why Shift dropped the engine behind the driver for optimal weight distribution.
This required some pretty impressive work on the chassis side of things, which started with most of the rear section being cut away and a firewall placed behind the driver. Then, it was on to the construction of the complex tubular frame, which is fixed onto both the shell and the Xtrac transaxle six-speed sequential transmission. So effectively the gearbox is used as a part of the chassis and as a mounting point for the pushrod-type rear suspension layout.
The dry-sumped RV8J engine is extremely low within this rear tubular subframe-and yes, this is no 3.5L V-6, but a fully race-tuned Toyota 3.0L V-8. Capable of developing a massive 550 ps in Formula Nippon single seaters, the tiny Toyota V-8 has been forced to breathe through 24.8mm air restrictors and has been re-tuned for more midrange power. While 300 ps and 300 Nm might not sound like much, on a fully fledged 1,200kg racing car, it's more than enough to put down some serious times. The RV8J is fed air through a massive carbon roof scoop, which doubles as an airbox. Spent gasses are expelled via a pair of equal-length headers and a straight-through exhaust.
Due to the rather unconventional engine positioning, the bodywork has been engineered to be very easy to remove, so that as soon as the car comes in the pits the mechanics can peal off the rear carbon doors, rear carbon window cover, and trunk lid, giving them access to all of the components. An air jack system allows the car to be lifted up instantly with a small shot of pressurized air.