self-learning boost controller??

[borry]

quote from the Apexi website... "Power FC allows the user to access a full self-learning boost controller"

can anyone tell me what this means?

[RbHed]

i think it means it has a optional boost controller... same as d avrc but u use d power fc handset

[raist60]

I reckon it means that it can set boost based on actual pressure rather than duty cycles / gain etc.

[borry]

hmmm... confusing. Anyone alse?

i just bought one (2nd hand) for my PFC and decided to get some info about it. I couldnt work out what that self learning thing was all about? unless its just some some marketing hype?

[b2barker]

As an engineer who sets up various control loops in industry I will have crack. A controller typically has three values of interest:

Setpoint (SP) - The amount of boost you want

Control Value (CV) - The output to the variable bleed valve, or pulsing of on/off valve or pushing/pulling the wastegate itself.

Process Value (PV) - The amount of boost you are getting.

To manually set one up you would typically make a step change to the CV (eg. valve from 0% to 50% open) and measure the response to the PV (how long it takes to reach the final boost value, and rate of change). With these measurements you set controller such that it gets the value you want as soon as possible, with little over shoot, and then hold where you want it.

A "learning" controller does this for you. While learning it changes whatever it varies to effect boost level and measures what effect it has on boost with your setup (ie. your turbo, your exhaust, ambient temp etc.).

It's not hype it's necessity. If it doesn't learn you would either have slow spool up or overshoot.

[borry]

good work b2barker. so the end result of having a learning versus non learing is.... faster spool up, less or no overboost? is that correct? any other benifits?

[diduc]

isn't this called fuzzy logic?

my profec A have to be manually adjusted for each boost level like 0.7bar, 0.8bar etc. I find with it gives more down low torque with 0.9bar then 0.8(stock turbo, s1 r33)..

[GTR R32]

with the GReddy Profec A, its learning mode is used to learn the features of the actuator type, external wastegates, and the stability of the boost curve. There are two learning phases:

1. Learns the stock base boost level

2. Learns the basic boost curve and the difference between the pressure in the wastegate and the pressure in the intake manifold.

You need to run the learning mode again after any changes are made to the characteristics of the wastegate spring or the power output of the engine.

Not sure about the apexi boost control kit for the pfc, but would assume it is similar.

[GTR R32]

for example, after installing my pfc, Z32 afm's and cam gears, I had trouble with boost spiking and then dropping off at high rpm. After running the learning mode it now once again holds my desired boost level spot on through the entire rev range.