Anti -lag

[rob82]

Just looked through a few of that maps defined by a few EVO9 XML's and it seems there is a anti lag AFR (or something along those lines - laptop at work). I would be 90% sure that the map is a lean crusie map and has nothing to do with turbo spool or response. It may be a feature they put in but never enable due to emmissions.

[mtcavity]

I have been questioning these tables for the whole time I've been looking through Mitsubishi ROMs, and recently updated all XMLs with the maps.

The only reference for the tables was a previously disassembled EVO 8 ROM, but puzzled me why I was finding the maps on naturally aspirated models.

Salex has mentioned in previous posts, that they could be defunct maps with no use.

Please explain what exactly "lean cruise map" is (is it open or closed loop based, and the input/output of the “circuit”)? The map itself is based on AFR, although the LOAD and RPM are based on Ignition scaling (?). Basically, try to explain the overall physics of the maps design (the best you can). Anyone else have any thoughts or input on this?

I apologize if this has gotten everyone excited about the "anti-lag" feature on the EVOs that contain these maps. The maps just fit into the pre-defined ROM I used as a comparison. I felt releasing the definitions would stir some discussions and get some input/answers to the maps use, and here we are.

I will be (again) be updating the XMLs to reflect the questionability in the definition and label it developmental.

Again, sorry for any inconvenience AND thank you for pointing it out.

[salex]

To the best of my knowledge, these maps have yet to prove their usefulnes .
IMHO, we just don't know what to do with them yet. It is very strange that they exist in naturally aspirated engines.

However, I have seen this happen with other ECUs (European mainly).
Naturally aspirated and turbo cars that share the same/similar ECU types.
There are unused maps in the naturally aspirated verions, which become useful in the turbo versions.

Next time on the dyno, I will try again to see if they change anything.

[rob82]

I have been questioning these tables for the whole time I've been looking through Mitsubishi ROMs, and recently updated all XMLs with the maps.

The only reference for the tables was a previously disassembled EVO 8 ROM, but puzzled me why I was finding the maps on naturally aspirated models.

Salex has mentioned in previous posts, that they could be defunct maps with no use.

Please explain what exactly "lean cruise map" is (is it open or closed loop based, and the input/output of the “circuit”)? The map itself is based on AFR, although the LOAD and RPM are based on Ignition scaling (?). Basically, try to explain the overall physics of the maps design (the best you can). Anyone else have any thoughts or input on this?

I apologize if this has gotten everyone excited about the "anti-lag" feature on the EVOs that contain these maps. The maps just fit into the pre-defined ROM I used as a comparison. I felt releasing the definitions would stir some discussions and get some input/answers to the maps use, and here we are.

I will be (again) be updating the XMLs to reflect the questionability in the definition and label it developmental.

Again, sorry for any inconvenience AND thank you for pointing it out.

Lean cruise is function that usually operates in an open loop fashion that enleans the fuel mixtures to gain fuel economy. It has been used here in AUS till late 2003 within Delco, ECC and Delphi ecu's. It usually is enabled based on coolant temp and also a time a speed threshold. Once enable it has a lookup table for desired AFR based on RPM and whatever the load axis is.

I personally have never found this map in any early model mitsubishi roms and or anything japanese during emulated tunes, so its a surprise for me to see it in the late model EVO's.

Its use has been discontinued due to the increase in NOx levels as a result of a lean burn however the reduction of COx in my mind would be better for the enviroment anyway. The reason it has been dicontinued is that NOx combined with photochemical smog creates ozone depleting chemicals. Go figure - in AUS there is very little smog near the highway zones where the function is enable!!!!

This is why I believe it has nothing to do with anti lag. As a lean burn may aid a little in spool but nothing compared highly retarded igntion event.



I would have thought that the anti lag function would be based on TPS vs ignition retard amount with an enable and disable rpm point. There must also be a TPS based desired boost lookup table - perhaps TPS vs a multiplier of overall desired boost. Otherwise how does the ECU know went to start driving the boost control solenoid?

[oracle]

Anti-lag does work even without retarding the ignition.
It uses secondary air system to blow the air and also injects fuel I think via the injectors. You get the bang-bang and the turbo remains spooling during gear changes. What effect it has on the turbo I'm not sure? But it will put more stress. Also it is load dependant I think.