The headers transition into 3″ tubes that merge via a 2 into 1 Burns merged collector. From the merge the Y-pipe goes to the turbine housing.
The way that everything now packages, the twin 60mm Turbosmart Powergates can have an ideal mounting location for the best flow, right past the header collectors with the discharge in the direction of flow. In a low boost engine like this, up to 60% of the total exhaust flow can be discharged by the wastegates. Because of this, paying attention to good wastegate flow is an often overlooked yet important attribute for power production.
The Turbosmart Powergates exhaust up and out through vents in the hood.
Our exhaust system is coming out with a near optimal configuration. Good tuned length, good accessibility of critical parts, vastly improved weight distribution. Protection of sensitive parts from heat and improved protection in a crash are all important considerations in the design of the exhaust that are being taken care of in the redesign.
Even though the engine is a stressed member, solidly mounted in the chassis and the turbo is mounted to the chassis, the exhaust system needs to have some flex built into it to prevent cracking. The header collector is left as a slip fit to the primaries, held together with springs. We will be adding flex bellows to the Y pipe before the merge to allow expansion and contraction without adding stress to the tubing that can lead to cracking.
The Y pipe with routing to the turbo is shown here. Everything routed cleanly and smoothly.
The wastegate actuators should be protected from extreme heat as even the silicone and nomex diaphragms can only withstand about 400 degrees of continuous heat. Many fabricators forget about this and place the actuators where they get baked by header tubes. This can result in wastegate failure and sticking.
Even the best wastegates can fail by overheating Low boost and large displacement engines can be hard on wastegates as well because the valves are open a lot and flowing a lot of hot exhaust gases, heating the wastegate up.
Previously, the wastegates on this car did not get any cooling airflow and there were some minor issues with the springs fatiguing with heat and sticking open, losing boost. Our actuators are now out in the open and faced away from the hot exhaust tubes while being exposed to cooling fresh air. The wastegates will not get hot anymore.