Twin PFC guys PC and WG
10-08-21, 10:42 AM
#26
so boost can't go up much more, if duty is already at 90%.
the Duty number is, in theory the duty the solenoid starts at, then it looks at the current boost, and your boost target and adjusts. theoretically having a starting duty that is low would have a slower boost onset, so it'll go to whatever boost 70 get you, and then ramp up. if you set it to 90, it might spike and then come down.
you might try lowering the target to like .9 or .95, and then raising the duty and see what happens. make small changes, and then you can bring it back to 1.0. i guess with the duty too low its a little laggy, and with it too high it get spikey. so you need to adjust, and see what it does.
if you change the rpm points, i think it does change what the pri/sec does (or i should say when), but it also changes when the turbos switch, so its a separate thing to tune.
one thing at a time
the Duty number is, in theory the duty the solenoid starts at, then it looks at the current boost, and your boost target and adjusts. theoretically having a starting duty that is low would have a slower boost onset, so it'll go to whatever boost 70 get you, and then ramp up. if you set it to 90, it might spike and then come down.
you might try lowering the target to like .9 or .95, and then raising the duty and see what happens. make small changes, and then you can bring it back to 1.0. i guess with the duty too low its a little laggy, and with it too high it get spikey. so you need to adjust, and see what it does.
if you change the rpm points, i think it does change what the pri/sec does (or i should say when), but it also changes when the turbos switch, so its a separate thing to tune.
one thing at a time
10-08-21, 11:21 AM
#27
when the duty cycle chart is basically a square like that, fixed near max, it means the ECU is trying to hold that valve shut. So the WG will be completely closed before the transition point and the PC should oscillate to control the boost. Then when the transition happens (TCN and CCN bits switch), WG will start moving and controlling boost.
if you are at like 5000rpm and the WG is still closed with very high duty cycle and you're not getting the boost you want, it could be a mechanical issue with an air leak (boost or exhaust leak), the turbos aren't performing as they should, or you should consider replacing the solenoids with 3 port design. 3 port solenoids from MAC will help vent more air out of the wastegate diaphragm.
As mentioned above, normally you don't need a super elaborate method to tune this, but it's helpful to look at the logs if it's not behaving as expected.
if you are at like 5000rpm and the WG is still closed with very high duty cycle and you're not getting the boost you want, it could be a mechanical issue with an air leak (boost or exhaust leak), the turbos aren't performing as they should, or you should consider replacing the solenoids with 3 port design. 3 port solenoids from MAC will help vent more air out of the wastegate diaphragm.
As mentioned above, normally you don't need a super elaborate method to tune this, but it's helpful to look at the logs if it's not behaving as expected.
10-08-21, 11:47 AM
#28
Maybe I should have prefaced my messages. My boost target 14.7psi is holding well. There is a delay if I punch the throttle at 5krpm before it gets into boost.
I will try and play around with the duty to see what it does, but I was more interested in the PRM ranges for the low and high and if it could get me into boost faster with a lower setting relative to mine.
I will try and play around with the duty to see what it does, but I was more interested in the PRM ranges for the low and high and if it could get me into boost faster with a lower setting relative to mine.
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j9fd3s (10-08-21)
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