Decided to add a bit more depth to the MAT timing adjustment. MAT, MAP, RPM, flexfuel based adjustment now.

Now the ECU pulls the standard MAT adjustment, checks MAP and decides which table to pull from (adjustable but set at 65kpa = high table). Then it pulls another table that multiplies the timing adjustment by RPM. It also takes into account the flex fuel blend ratio and subtracts from the multiplier.

Calc: Spark timing advance = Timing - (MAT adjustment * (MAT RPM % Multiplier - (FlexBlendRatio * 8)))

So if Advance is 30 degrees, MAT adjustment = 5 degrees, Flex Blend ratio is 10 (full e85), and RPM multiplier is 100% @ 3600 and MAP is HI then: New advance = 30 - (5* (1.00 - (10*8))) = 29 degrees.
But if flexblend is 2 timing = 26 degrees.

If advance is 30 degrees, MAT adjustment = 5 degrees, FlexBlend is 0, RPM is 20% @ MAP 30kpa then: New Advance = 30 - (5*(0.20 - (0*8))) = 29 degrees.


I have the code 99%, but forgot to add in a safety stop to the flex fuel subtraction so it can't go negative.
Testing NOW
Once finalized and checked I'll implement this into the Flex Fuel bin.

 

Added a Scalar to adjust the MAP value.
Added more resolution to the RPM tables.
Been running this today. Nice to have timing more optimized for conditions. Now I can tune off weather and heatsoak instead of dealing with seasonal changes.

 

Interesting... Do you find there's actually sensitivity to spark timing over various air temps.... noticeable by SOTP?

 

Massive. It helps to have the shift and cel flash when theres KR so I see it live constantly.

maybe it’s an extreme weather AZ thing.

I tuned last week multiple hard passes at 60 degrees. This week constant KR due to 80 degree weather.

All newer cars do it so theres obviously a good reason for it.

 

Wow... interesting.

Mine was very sensitive to fueling via MAT... But i don't notice much behavior change via knock retard in any particular weather.

i still find it cool you're able to modify the code like that...

 

I am actually surprised you haven't seen this with the tuning you do. It's been an issue with every car I've ever owned. Maybe I tune closer to the edge?

 

I always see some knock retard to the tune of about 1 to 2°, but it doesn't seem to get worse with ambient temperature... largely glancing at the TP data as I pull some hard load on the freeway.

My timing map is pretty aggressive too... After my false knock investigation from a few years back and how I was able to characterize what it was, I lost my fear of getting more aggressive with spark timing.

 

big time here in az, youll have darn near 200 degree intake air temps sitting at a long light..

 

Hmmm maybe its because of my cold air setup... mine never gets beyond about 15 degrees over ambient temp...

 

Sounds like IAT not MAT. Even IATs are at least 20 over depending on the car when I’ve paid attention.

When the street is radiating 180 degrees it’ll do that.

It’s always funny to me how different AZ is to the rest of the country.

 

Just took a drive at the hottest part of the day and didn’t see my typical kr blips AT ALL. first time in years.

this code is amazing.

Added to FlexFuel Bin