V8 ITB with ETC and IAC .. how to do it smooth

[Matus]

Hi guys,

So Now I have running engine with working ETC however too aggressive throttle reactions. I would like copy BMW approach from S62 & S54 where they are opening throttle bodies just from "higher load"   

as far i seen stock M3 & M5 is using idle valve to operate in first 10 -15 % of pedal but also checking pedal acceleration.

How I should configure IAC opening regarding PPS and also overlap with ETC ?a


actuator is stock S62 ITBs with injectors are S62 too however heads are modified M62 with engine block M62 with stroker to 4.73L

[Kamuto]

just fill etc  target table how do you like it to be

[Matus]

It is what I did actually, but it is not smooth enough. I have acceleration issues on pit line and also handling car by throttle during cornering is too scary

You know I have 50mm throttle body for every cylinder, so it is sensitive for every degree.



I was considering if IAC DC max effect on ETC target is not doing this "overlap" or something else ?

[Matus]

Or if   " IAC position follows TPS when not idle " will be changed to ... follow PPS .. than ti might be easy to set ETC to start from "lower duty cycle for example" or  PPS to Throttle target will be starting from 5 % of PPS .. for example

[Kamuto]

Or if   " IAC position follows TPS when not idle " will be changed to ... follow PPS .. than ti might be easy to set ETC to start from "lower duty cycle for example" or  PPS to Throttle target will be starting from 5 % of PPS .. for example

maybe spark trim depending on speed will help? not sure about that

[gunni]

That TPS / PPS table is far to aggresive with large throttle bodies.

Look at your VE table and for the sake of it look at what your MAX VE is at 6000rpm, then look at where you have half of that.

Put 100% PPS @ max VE
Put 50% PPS @ 0.5x MAX VE cell at 6000rpm

I would guess something like

PPS - TPS
0  - 0
15 - 3
40 - 16
60 - 35
80 - 50
100 - 100

I normally map race cars to have linear torque delivery.

[Matus]

I see, yaa one think is set it more "gentle" however .. that topic was to simulate OEM feature.

However fair enough 
I am adding VE and IGN table for overview. I didn't set anything dramatic yet

Injector size 14.9  (257cc/min  Stock S62)
VE table



IGN table ( in real 5deg more than mentioned in table, as I measure difference by lamp later)



Engine wasn't fine tuned yet as I did lot of modification and also it is my first ecu installation so suggestions are appreciated.

[gunni]

The VE table is always increasing with TPS, so fix that

21% TPS and above and 2000rpm and below are needs looking at

Ignition looks safe. Can do with 10degrees at the very low end, below 30% TPS, then smooth into the top ignition, don´t forget that in alpha-n load is not directly proportional to throttle angle so 50% TPS ignition can possibly not be much higher than 100%

[Kamuto]

connect map sensor and leave ignition on map only tps is stupid I believe that 20% tps on 2000 rpm is 100kpa that's why ve does not change a lot

[gunni]

100kpa behind the throttle body and 70% TPS doesn´t have to be the same as 100kpa and 100% TPS, this is due to the nature of turbulent airflow past the throttle blade and the small volume behind the blade. This is especially true between 70-90kpa on a ITB setup. Best is to just map it via TPS for fuel and ignition.

[Kamuto]

100kpa behind the throttle body and 70% TPS doesn´t have to be the same as 100kpa and 100% TPS, this is due to the nature of turbulent airflow past the throttle blade and the small volume behind the blade. This is especially true between 70-90kpa on a ITB setup. Best is to just map it via TPS for fuel and ignition.

not the best yes before I was doing it on tps too, but could not get perfect mixture when car is on load and when you are trying to hold rpm at the start line map sensor cured it map correction table filled with 100, now whatever load is you get map multiplication and perfect mixture in every spot