Are traditional wastegate spring changes potentially a thing of the past with Turbosmart's 'StraightGate50?'
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Stewart Mahony from @TurbosmartHQ gives us some insight into what a boost or vacuum-actuated straightgate can and does do compared to the traditional poppet-style wastegate options.
One of the first questions on your mind might be how much this butterfly valve will leak. 0.006% is the answer thanks to specific valve seat design considerations that are different from a throttle body where we typically see butterfly valves in use.
Turbosmart claims the self-balancing nature of the StraightGate50 means a huge tuning window of over 5 times base spring pressure can be obtained with Stewart stating they had no issues from 5-35psi on their test rig using a 3-port solenoid, 5lb spring at 45% duty cycle. 35psi was the limit of the test rig, not the straightgate. Note features listed since this interview (included below) state 6psi to 42psi of control with the supplied base spring.
Compared to the electronic version the boost or vacuum-actuated option gives those without a somewhat uncommon 20Amp H-Bridge output on their ECU or an external H-Bridge module another option as well as more friendly emissions considerations in relation to OEM style vacuum-actuated control as discussed.
It's mentioned and worth noting the StraightGate50 (pSG50 or pSG50v) 50mm butterfly style flows more air at 383.9 CFM than a traditional PowerGate60 (WG60) 60mm poppet style at 360.9 CFM, and without the requirement for a 90-degree turn in the wastegate flow and also heat dynamics are changed for the better, all with a wider window of precise control. Some of this does come at a cost though with the max safe pressure ratings for the StraightGate50 being 100psi vs 220psi for the PowerGate60.
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