What is "WastegateDutyCycleRPMBoundry1"?

[boostin1989]

What do the "wastegate duty cycle rpm boundry #" values do? I'm having a problem with my boost control and am wondering if knowing this might lead me to the issue.

My car makes minimum boost (Tial wastegate with a 6 psi spring) up until ~4200 rpm. Once I get above this RPM the boost goes to the set 16 psi for a short while, then starts to fall off back down to around 10 psi. The wastegate boundry values are set in the RPM range where my boost goes up to the set value.

[ShelGame]

That's the RPM boundary for the adaptive WG control. It only affects the adaptive portion of the duty cycle. Not the base DC. Did you adjust the WGDCFromBoost table at all? The factory table only goes up to 13-14psi. The adaptives are only good for a couple of psi worth of control.

[zin]

Would this be a good place to ask for a quick tutorial on how the factory controls boost?

It seems like there is a baseline PW for a specific boost level? Are the adaptives used to trim that PW to fit the desired/target boost level?

Frankly I'm surprised there would be a need for an adaptive on boost, I guess I always figured the MAP would give an accurate account of where boost was, then the computer would just modify the duty cycle to maintain the target boost... BUT, it seems there is more to it, at least in this case. I wonder if it saved memory space, or lessened the computational load on the processor to do it this way? (or whatever way it is actually being accomplished...).

Mike

[ShelGame]

There are 2 tables that lookup the 'base' WG Duty Cycle (it's duty cycle controlled, PWM, fixed pulse rate - I forget the total time). The main table is the DutyCycle from Boost Target. The other is Duty Cycle from RPM, but it only modifies the base duty cycle. The adaptives are there for the same reason as the fuel adaptives - to compensate for changes in the system like oil buildup, turbo wear, etc. Like I said, the adaptives only seem to adjust the duty cycle +/- 25% which equates to only a few PSI. You can turn the adaptives off just like the fuel adaptives. I put a note in the KC about that...

[boostin1989]

Rob,

I haven't adjusted the WGDCFromBoost table. I'm assuming that I need to lower the duty cycle since it seems that the solenoid is staying open too long and lowering the boost.

Also, what is the "KC" you referenced?

[zin]

Also, what is the "KC" you referenced?

KC is short for Knowledge Center... Lots of good info in there, though much of it hasn't been "ported" over from the old version... (yet).

Mike

[ShelGame]

It depends - what cal are you running? The T-SBEC & T-SBEC cals use the T1 style boost control where more WGDC equals more boost. T-LM and all the other T2 based cals are the opposite. Less DC equals more boost.

[boostin1989]

I'm running a T-SMEC turbonator V16 cal. I have my wastegate setup as a T1 style (i had it setup as the original T2 at first and this had me stumped for a couple weeks :banghead:). I'm going to try turning off the adaptives and increasing the dutycycle to see how she turns out. I greatly appreciate the input guys.

[boostin1989]

Increasing the duty cycle fixed the problem of the boost falling off as far as I can tell.

Any ideas why the boost would stay at minimum until around 4500 rpm? One other interesting note is that the rpm that it goes to full boost drifts between ~4000-5000 rpm. It's like an on/off switch when it reaches the point the computer decides to allow full boost.

[ShelGame]

Increasing the duty cycle fixed the problem of the boost falling off as far as I can tell.

Any ideas why the boost would stay at minimum until around 4500 rpm? One other interesting note is that the rpm that it goes to full boost drifts between ~4000-5000 rpm. It's like an on/off switch when it reaches the point the computer decides to allow full boost.

What does the AllowedBoostFromRPM table look like? It is usually set to a lower boost level below 3500rpm or so...