1. I deliberately didn't reference the table as I don't have your actual ROM in front of me disassembled, but there are two tables, one that affects the lookup for the airtemp in the airtemp/baro table you've been adjusting, and the other one that affects load which is the one I think you should adjust. Without having your disassembled ROM in front of me, the one I suggest you adjust is the one mentioned in post #12.

2. Load is already varying by large amounts with air temperature. If you increase the density reading in the table at a given temperature, you'll increase the recorded temperature compensated load at that temperature in proportion. Vice versa for decreases. However, at your "home" or "standard" temperature there will be no difference, so if your tune is right at one temperature you need to adjust the temperatures around it that are not so that they become correct. Like others though, I don't see these wild variations on the standard arrangement.

3. No it isn't that hard, it is just yet another thing to do... plus I think it is better how it is. Maybe try adjusting the table first?

4. Yes there are coolant temp tables, mattjin has described them well, perhaps you need to make sure you have a plateau (if you don't already) in the adjustments once you're over say 75C coolant?

 

Alongside #2:

When I log the oldschool 2byte load is it this "compensated load" value you're talking about? I seem to remember there is a "more correct compensated load" than the old 2 byte that I'm using. Maybe these are one and the same.

I'll look around for Mattjin's description of coolant enrichment. I don't appear to have the map for it in my 94170014 tephra rom.

 

The original 2 byte load we started logging was not compensated for baro or temp. On the IX, if you add 6 to the address (on mine FFFF6B18 rather than FFFF6B12 IIRC) you get baro and temp compensated/corrected load.

 

Thanks man, but I've got an 8 w/ 94170014 rom. Still using this old guy:


I wouldn't even remember how it works.

 

Funny how the table was given in the beginning of the thread, but nobody wants to try adjusting it. :-)

I had a play with the table a number of months ago and it will do exactly what Honki needs it to do, it. For my own car I did not need to change anything, but rather I was just on a search to find it.

But my big question is what is happening to see such excessively high intake air temps? Even on a 46C day here (115F) and sitting still in traffic heatsoaking badly, with an auto trans in gear causing more engine load, and the A/C blasting away, I still have not seen anything over 75C in the intake. Have you checked if the air temp sensor is covered in some crap causing false readings?

 

yea, its not the sensor. My thinking is the upgraded IC is having an effect.

Follow me here, now the OE air density is based on lab tests with OE. Now say you upgrade the IC and cool down the post-turbo air tremendously compared to stock. So rather than 70F temp air getting sucked into the MAS that goes into the TB at, say 100F... that same 70F air is only 80F when it hits the TB. (I use water/alcohol injection too so I think it's possible.) Now the same 70F air at the MAS temp sensor has a higher density than anticipated. Now your temp compensation table is off.

That's just a theory. The idea is nonlinear since heat transfer would be worse at higher ambient temps... so the same may not be true at high temperatures. Perhaps my modifications dramatically decrease charge air temps when ambient is relatively cool, but they perform near stock when temps are high. This would require me to rescale the air temp compensation for IPW. I'm trying this table you guys suggested in the first place now. I tried an itteration on the way home and 5% wasn't enough to get my AFR in the right place. I'll try for 10% tomorrow.

 

Do you have an aftermarket filter assembly?

 

Tried 10% this morning, still not enough. I'll try another 5%. ...lol I'm not yet convinced this is the table I want to change. The other one was much more responsive and held AFR more consistant. I'll keep trying.

Out of the goodness of someone's heart they wouldn't want to give me the addresses for the high and low bytes for the corrected 2byte load for the 2003 evo 8 94170014 ROM would they? (EvoM's search really does suck)

 

that did it.

My first 3 columns are now tuned. I've got to wait for it to get warmer to get the other columns. BTW, I notice that my MAS air temp sensor is always 10F above the actual temp even on startup. Not a big deal, just calibration I suppose. So long as its precise the accuracy can be accounted for.



Edit: After looking over the logs some more I'm becoming increasingly uncomfortable with this method. The results are terribly inconsistent. On my first 4-5 pulls It will be too lean and then after that it will come down by ~.5AFR to where I want it each time. When I changed the other table I got consistent AFR offsets. I'm going to do some more comparisons.

(I, of course, always do my pulls at operating temp)

 

Getting there!

 

Okay, I've determined that I don't really like to tune the air density table because my AFR doesn't seem very stable as a result. The other table seems more consistant... but with both tables I get a different AFR when I'm running the car hard vs. when I just do pulls. If I run it through the gears aggresively as though I were racing I see .5-1 AFR richer. It is strange. I don't know exactly what's happening there... maybe spark is missing or I'm getting a little blow out? Don't know. I'm still trying to work this out, as you can imagine I can't just go ripping up and down the roads to get AFR right.

 

Do you still have lean spool enabled?

 

I think you may need to reevaluate here. If the mass airflow sensor sees X frequency, Y baro, and Z IAT, the mass flow rate is M. The ecu calculates the amount of fuel needed to reach your desired AFR based on M. It doesn't matter if you drop intake temps to -40C post intercooler, the amount of air the air meter read is correct and the desired AFR will be reached.

The only caveat here is that if your IAT readings are so high that they put you into a map that intentionally enriches the mixture to keep the motor safe.

Have you been using the water/meth injection this whole time?

 

Could it be that the water/meth flow rate is unstable?

 

It definitely throws a HUGE variable in this. Especially considering most of us find our AFRs to be fairly stable with air temps.

Considering the water/meth has ZERO compensation for air density. Even if the water/meth delivery is rock solid, it's going to cause HUGE changes in AFR with temperature changes.