Boost creep problem
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#27
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my wastegate is at a 90 at the merge and seems fine... 9 lb spring made 9lbs. 10.5 lb springs make 10-11 pounds. One time i believe i installed one of the springs wrong (like it went sideways and got pinched when i bolted it together) and with 10.5 lbs of spring it would go to 15psi where i would let out of it.. running reference off the turbo.
#28
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When I ran the TC76 I could control boost down to 6lbs with a turbosmart 38mm gate. After I switched to the PT76 I could not control boost at all with the cutout open (15-16lbs). I installed a 46mm precision gate to try and solve the issue. With my cutout closed going through the factory slp dual dual exhaust I can run down to 6lbs, when I open the 4" cutout somedays when it's cooler it still creeps really bad, but somedays when it's not so cool it will run around 8-9lbs. The issue is less back pressure and not the greatest wastegate merge angle.
The more post turbine back pressure you have the higher pre turbine back pressure will be by an exponetial rate. Obviously lower back pressure makes controlling boost much more difficult. As the engine size decreases it's more difficult to control boost as a direct result of less back pressure.
The more post turbine back pressure you have the higher pre turbine back pressure will be by an exponetial rate. Obviously lower back pressure makes controlling boost much more difficult. As the engine size decreases it's more difficult to control boost as a direct result of less back pressure.