I believe the reason we are seeing 20psi of boost pressure is because the FP calibration is allowing it to get that high. Regardless of ambient temps the stock calibration will command the wastegate to regulate boost to 18 pounds so in theory a stock ST should never see higher than 18 unless there’s a boost creep situation which I don’t believe is an issue with the ST, certainly not at stock boost levels with stock turbochargers. Does anyone know if wastegate duty cycle has a PID? My GTR has one and I never looked when I set up my datalog PID list.
I would agree that “yes” the FP tune is allowing it to get that high, but there is a caveat to that. It’s totally dependent on a bunch of factors. Usually the peak boost is observed right before a shift. So it’s not “really” seeing that max boost, but for a very brief time. Usually, but I don’t have a FP tune, so making a bit of an assumption based on looking at a lot of eco logs with vacuum WGs
These, like all other eco platforms are torque based. How they hit the desired torque is based on a bunch of factors and inputs. If you boil it down to something super high level that doesn’t tell a bunch of the story, it focuses control around throttle opening, boost and timing. The stock strategy will actually try to leverage timing over boost to a certain extent. As an example, I worked through building my own tune and testing a few methods based on courses I took. I found that if I didn’t increase driver demand, but would allow it to take more timing advance (obviously keeping safeties in place based on inferred octane, KR, etc.), that the car would reduce boost, but increase timing advance and still hit the same desired load/torque. I did three versions with this method and would have to go back and look at logs, but there was a significant decrease in boost, while timing was higher. I tested these at try track and ran within the same tenth.
Sorry for the ramble.
Anyway, yes there is a WGDC channel in HPT and the same PID in SCT. The channel in HPT is set so that the lower the percentage, the more WGDC is being used. Because I have a little elevation where I am, it’s one I pay close attention too as I am always fearful of over spoiling since popping a turbo on my truck.
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