Evo 9 ECU change

Hello,

So I have a question, my Evo 9 has had the OEM ECU tuned originally I was going to keep the OEM ECU but I'm about to change it out for a Nexus s3 for better functionality and tuneability

My question is depending on the way it was tuned would there be any issues writing the maps from the OEM ECU to the s3? I guess it's going to depend on how it's controlled where its maf, map or time based. But if they're the same? Or would you suggest starting from scratch?

The initial set up will be obviously be from scratch. But once that's all done?

The mivec map I'll have to copy across. Cell for cell as it's been tuned

Any information would be great thanks!

Hi. What you need to remember is the numbers that you see in the stock fuel map aren't necessarily the values in AFR that wideband O2 sensor is measuring. Some tuners make them match some don't. So if you want to use those numbers for another ECU you need to make sure they are real AFR values first. Ignition timing values can be copied but again you need to remember that in stock Evo ECU they are based on engine load (means on measured air mass entered combustion chamber) and not on the boost while in most speed density ECUs it's based on boost. You can use it as a general guide as it will be close to final numbers but it's not exactly copy and paste exercise.

Ahh yeap ok

It's had a dual map tune for ethanol, that's where I'm going to have to be cautious is copying those values over as they would have just scaled the lambda to suit right?

By the way- most people don't realize what great potential stock MMC ECU is capable of. It even has CAN protocol inbuilt from factory.

Check out an example of what it can do in right hands- more that many advances standalone ECUs))

https://youtu.be/yOwNb_z4Z8A?si=Vew87ujXs7XPx1IV

https://youtu.be/_K0qbaMj4aM?si=mDOnTzGXTcEMmG_u

Please take a look at the stock fuel map I attached. At 2500 RPM and 260 load (which is about 1.7 ish Bar boost depending on ambient temperature) the target AFR value is 9.1. That isn't what your real AFR value is going to be measured by wideband O2 sensor. So if you'll copy and paste these numbers they will be way off. First you need to make sure the values in that table match the actual AFR reading by wideband O2 sensor.

Thanks

I do understand they are a very capable OEM ECU, but due to some limiting factors I face I thought that it would be a better option for me to go aftermarket.

And I have always had trouble setting up Evo scan and ECU flash. I have thr correct open Port connector.

That fuel map is time based Right? Or is that mass air flow?

I haven't seen grams/second before but I haven't really looked into things like this