Engine Pressure Ratio as load source

[ReubenH]

Hi all,

I haven't started hooking into it yet however am looking to do some fairly fancy things on the tune to make it more robust around varying emap pressure (+ some other things that I won't get into on this thread)

Have any of you attempted to do something around this? 

I have made a math channel that is MGP - Exhaust Pressure

It appears that I can drop that into the fuel table as load source however the units do not work
(Note the lack of (kPa) on the end)

Vs 

One of the other more different things I am going to attempt is having VCT position (probably only intake cam although I might use overlap instead) act as a multiplier to the VE table 
This may allow me to use different VVT positions without much (or any..?) ve table changes after the fact...

[Adamw]

I tried using pressure ratio many years ago when I used to use Autronic a bit, to me it was a very unintuitive strategy to tune and didnt seem to give me any advantages over a more traditional MAP based multiplier so I didnt bother with it after a couple of cars.  This was on restricted rally cars so you would have thought it to be an almost ideal application with the compressor near choke and the turbine working very hard.  

The un-intuitive bit is you end up in the same load site at idle as you are at WOT, its only really over-run and cruise where the load site deviates more. 

Note what you are showing above with a math block on the fuel table load axis is just the "VE look-up", this is only half of what you need for a pressure ratio based SD calculation.  The equation load source really needs to use pressure ratio instead of MAP.  

[mapper]

TP vs RPM and PR vs RPM on 4D might work