We all remember when MRFRED discovered that there was many different loads (5 total, 3 main ones; RAW, temp comp'd and baro+temp comp'd). Then we remember when he discovered that the fuel and timing maps followed different loads at various temps/loads (Thanks again for all your work MRFRED). It was also brought up recently in the V7 and another thread.

So I thought I'd write it all out, so there is no confusion.

This matters most for people at elevation. When near sea level, the 3 different load are usually 20 within each other. But when you are at high elevation, the loads can have a big difference (ie 280 1/2 byte will be like 220 baro+temp comp'd)

So here it is...... (Maybe this should be put in the important threads stickied thread.)


=Regular Non-modded ROMs and V5 ROMs=
Timing maps use baro+temp compensated below 77F IAT. Above 77F IAT, just baro compensated is used.

Fuel maps should be using baro+temp compensated essentially all the time. Below about 20 load in closed loop, uncompensated load is used for fuel.


=9653 V7 ROM, 8859 V7 ROM & 8858 V7 ROM=
Both Fuel AND Timing BIGMAPS use the same Load that the Fuel maps would normal use (ie Load_Baro_n_Temp_Compensated)


=9417 V7 ROM=
Both Fuel AND Timing BIGMAPS use Load_RAW aka 1/2byte load

 

good info. thanks for posting. not a huge deal to me as Im pretty close to sea level. But can you also add in the info on how to log the various loads? Since Im trying to run v7, Id like to log baro+temp compensated load just so I know what Im looking at in logs directly correlates to the maps. Is it painfully obvious somewhere and Im just missing it? I swear the more I know, the less I understand...

 

Timing can also use a load adder depending on the status of a control byte that appears to be related to acceleration enrichment.

96530006 stock setting has this feature disabled, not sure if other ROMs do or not.

 

Just for the record, there are 4 loads: raw, temp compensated, baro compensated, baro+temp compensated. They are usually 2 bytes apart in that order in the ROM. So, if you know the variables for one of them, you should know all of them.

 

Thanks for the clarification Jay. Seems my SWAG was correct about 9417.

 

I knew there was 4 loads (actually MRFREDs many loads thread says there is 5), but I only mentioned the 3 I did because it seems that those are the only ones called on for timing and fuel look up.