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Does anyone know why the Wastegate Duty Cycles table is set to 50 from 25% TPS and from 0-2250 RPM?

I've read some interesting threads on MSF (namely "Wastegate control, Boost spikes and PID control"), but didn't find anything explaining this. These are stock values, which COBB left alone in the OTS maps.

I noticed that sometimes, when I blip the throttle while stopped in neutral (0 WGDC), the duty cycle shoots up to 98.65% for a quick moment (see 3rd row in attached log). I have a GrimmSpeed EBCS, so I can hear the solenoid tick when this happens. I changed those values from 50 to 0 and this WGDC "spike" went away. I'm wondering if 50 is used as a special value for some reason. The formula reported in that MSF thread is: Actual WGDC = 2 * table value + 10 +- 1. When you apply 50 to that, the result is > 100.

Any ideas as to whether or not it's OK to use 0 WGDC for RPM values < 2500?

View attachment wgdc_spike_datalog.zip
 

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the reason its 50 is because you would basically wanna slam the WG shut at anything below 200 rpms to get the turbo spooled.
 
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That makes sense... I was worried because people (e.g., COBB) say that it's not recommended to run the solenoid at more than 95% duty cycle to prevent it from sticking. But I guess it doesn't matter if it's momentary like that?
 

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........people (e.g., COBB) say that it's not recommended to run the solenoid at more than 95% duty cycle to prevent it from sticking. But I guess it doesn't matter if it's momentary like that?
Yeah, when they say "run it at 95%", they mean all the time when in boost. I use aftermarket EBCS....
 
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So a "50" in ATR = 100% duty cycle of the BCS, = 100% closed WG? Is the scaling linear from there, eg. "25" in ATR = 50% duty cycle?
 

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So a "50" in ATR = 100% duty cycle of the BCS, = 100% closed WG? Is the scaling linear from there, eg. "25" in ATR = 50% duty cycle?
The formula from the first post
WGDC = 2 * table value + 10 +- 1
was deduced by someone on the other forum (I can't remember who now) based on his observations. It's probably not very accurate, since the ECU doesn't exclusively use the Duty Cycles table to control the wastegate.

Yes, more duty cycle = less boost seen by the WGA (i.e., more boost is recirculated to the intake, bypassing the WGA) = less open wastegate.

Also, 0 duty cycle doesn't mean 100% open wastegate. The turbo must be making some boost (10-12 PSI for stock turbo) to mechanically overcome the WGA spring. The duty cycle is just a signal to the EBCS to bleed boost away from the WGA.
 
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