Pre-1.4 beta 10 boost control duty cycle

[E30_Driv3r]

OK, pretty sure I see the problem.

By design we wanted there to be one bias table. Blending is between the two boost target tables.
Say you have 150kPa target in one and 200kPa in the other and you are partway, you might end up with 180kPa.

The code should then lookup the duty cycle needed for 180kPa from the bias table.

However... there's a mismatch. The ini file is doing that and showing one bias table, but the code is actually using both bias tables and blending between them. (Oops.)

Can you think of any circumstances when it actually makes sense to use two bias tables? Do different fuels alter the turbo operation enough to warrant it?
Having two gives you more flexibility, but is more tuning. Our aim is to keep things simpler if possible.

Experienced users - please chime in!

James

IMHO, two bias tables aren't necessary even when running different fuels that effect turbo spool-up (IE. e85). In my situation some targets will only be targeted on one fuel type so there isn't a need to target the same kpa twice on two bias tables. If somebody wanted great precision maybe I can see the advantage of two bias tables but I prefer having just one simply handle both target tables.

[nathaninwa]

In what I have tested, I didn't see much duty cycle change running 116 vs E85. But my setup does not see any extra spool either. Back to back testing showed maybe an average of 50 rpm faster spool on ethanol over race gas

I'm fine with one bias table, but others may need different. Can it be setup to have an option to turn it on?

[Chiburbian]

How does this work with boost by gear?

given:
* target boost table value of 190kpa at a given rpm
* In 3rd gear with a boost by gear target of 180kpa

In a fully functioning properly set up closed loop boost control setup working as it should, is the boost limited to 180kpa at that given RPM?

Say the same target boost value but instead in 5th gear with a boost by gear target value of 210kpa? What would the actual engine boost value be (given all of the above?).

[nathaninwa]

As far as I know, setting it to boost by gear ignores the boost table value and uses the value you setup for each gear

You can test this with a datalog of your own targeting slightly different values and looking at the boost target in the datalog

[Chiburbian]

In the opinion of those here - would we perhaps like to have the boost by gear function changed to either a "limiter" approach as described above or perhaps a "scaler" that multiplies the target boost by a percentage in order to still maintain the same boost curve of the standard closed loop target map but would still allow lower boost levels in lower gears? If so, i'll find a way to suggest it.

[aidandj]

But the current method is really simple. Boost by gear, each gear has a different target boost.

[Peter Florance]

In the opinion of those here - would we perhaps like to have the boost by gear function changed to either a "limiter" approach as described above or perhaps a "scaler" that multiplies the target boost by a percentage in order to still maintain the same boost curve of the standard closed loop target map but would still allow lower boost levels in lower gears? If so, i'll find a way to suggest it.

I like the scaler idea.

[E30_Driv3r]

I loaded up the new beta 15 with the blending fix and it is now using my bias table. However, in basic mode no matter the slider position the code seems to still be ignoring my boost bias table and going straight to overboost. If it matters, I'm on ms3-pro so maybe its a bit different? That's the only difference i can think of between myself and everyone else.


https://drive.google.com/file/d/0B3GWeG ... sp=sharing

Look around record 8123 for the overboost events.

MSQ. attached as well. Will be very happy if someone points out something super obvious since I've gone through everything.