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The turbo, exhaust and wastegate is this small and compact unit. The turbo is a production Garrett TR30R.
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The turbo, exhaust and wastegate are all being bolted on. Everything is held together with quick release V-band clamps. The tubular 321 stainless exhaust manifold is covered with this Inconel and ceramic shield. You can't be setting that expensive carbon bodywork on fire!
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The turbo, exhaust system and wastegate all bolted in place. You can also see that the bottom of the engine support trellis is in place as well at this point.
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Professional motorsports teams can buy the TR30R turbo from Garrett and it is probably the ultimate medium frame turbo. The compressor and turbine wheel aero are customized to the specific customer needs to be as optimum as possible for the expected operating conditions. The compressor housing is made from magnesium, the center housing titanium and without water-cooling to minimize weight, and the exhaust housing is investment cast, thin-walled stainless. This makes the turbo light, very light. A TR30R can weigh as little as 7 lbs! The ball bearing center section has the highest specification materials to maximize durability under race conditions. Lastly, the wire hanging out of the center housing is a speed sensor. The speed sensor is critical when using a restrictor to prevent turbo over-speed. The TR30R was developed for WRC rally use but Garrett works with race teams to develop the turbo to their needs.
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The TR30R breathes through an ALMS mandated 42mm restrictor. Even with the restrictor this little engine makes over 500 hp and 442 lb/ft of torque. The external wastegate is water cooled and has a very efficient tangential mounting. It also dumps right into the exhaust at a good angle. Since a lot of the total exhaust flow is through the wastegate, having a good flowing wastegate is something that is ignored by a lot of people, wasting free power that is sitting on the table.
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The engine's heat exchangers for coolant, charge air and oil are in aerodynamic ducts on both sides of the chassis. The engine heats the oil very little, probably a by product of the ethanol fuel thus only about 20% of the car's oil cooling is being used. The designers did not anticipate this and thus a lot of the oil coolers space ends up being blocked off most of the time! This will have aero design repercussions in future iterations of the car.
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