Ignition Map Question On Apexi Ecu

[leeroy_25]

Guy's have been looking at various examples of maps trying to learn a bit about the Apexi ECU tuning. I was looking at ignition maps today an had a couple of example maps .. I believe one is pretty much the factory set one and the other is a tuned one. I noticed a very large difference in the max advance and range of advance between the two maps. Can someone please explain a bit for me. I think the factory one has the high peaks values. Surely these are too high for your engine or is it okay to have these at particular loads? Or maybe these cells are never used?

Just trying to gain some knowledge.

Thank you

Lee

[DVS JEZ]

each engine is different, But those maps are pretty high, you have to see where the car is running on the map on full load, my car runs along P16 on high boost, this depends majorly on how close your airflow meters are to maxing out etc.

high numbers in the timing in low load area's can be tolerated when the car is off boost just as if it's an Naturally aspirated engine(best way to set this is on a dyno and adjust the timing to find the best advance to power gained, hard to explain), but once it starts to ramp onto boost the timing numbers decrease radically, all this needs to be tuned to suit each engine and each setup, using knock detection.

the stock power fc maps have some stupidly high numbers say from P9 to P20, and the more boost you run the more you need to decrease the timing.

even the idle is pretty high, what engine is this map from? before any timing numbers are changed it is EXTREMELY important to make sure what the ecu is reading corresponds to what a timing light is reading on the crank, so the ecu and engine are in sync

[Don Dada]

before any timing numbers are changed it is EXTREMELY important to make sure what the ecu is reading corresponds to what a timing light is reading on the crank, so the ecu and engine are in sync

^^^^^^

This is crucial and may make two identical setups making the same pwr look totally different when it comes to numbers on the ign map

The 2nd map is the base pfc map for the 26 with a degree or two changed in some places and the first map looks pretty relaxed to me in the first 6 rows or so.

With my cas set to 20* i added 4* to the first 8x10 cells (2nd Map) and the car feels a whole lot better in the transition into boost and has no noticeable increase in knock....the question is how much more can it take because im not even sure if the knk sensors will pick it up that low in the rev range

The point is every car is different so is a matter of trial and error to see what works for you

[leeroy_25]

Thanks for the info guy's. The tunned map is a sample one I pikced up for an RB26. The base map is currently what I am running in my RB30. It has not yet been mapped fully as I am running it in on very low boost and 4500rpm max. Nearly done though.

I have checked my timing at the crank and it is set to 20-21 degs. I have noticed that at idle the commander says 23degs.. But I presume that depends where on the map it is sitting? I thought the base map looked high in some places! Heopfully fine how I am running now but I would like to learn for myself before I get it mapped!

Cheers

Lee

[JonnoHR31]

the ecu changes timing a bit at idle to lower and raise it.

45 is pretty normal under light load. i run up to 50 degrees advance in my map, with 40+ covering almost all the top half of the map. most of the time you'll reach MBT before it knocks under light load

[leeroy_25]

That's good to know Jono.. What does MBT stand for though?? I am sure it's obvious really!

So if the ECU changes timing a bit at idle.. ie depending on what the map says at that load cell.. How can you check that the ECU is reading the same base setting as you gun off the crank? Or do you not? I.e do you need to calibrate the two together somehow?

Only way I can think is you idle the engine and set the commander to 19-20deg advance at that load cell then set the CAS so the timing light also reads 19-20deg. Then you can tweak form there. But if idle is supposed to be set at around 20deg and my commander is set at 23 from the base map I am a little confused? i.e I set mine with the gun to read approx20deg off the crank. But the commander reads 23deg? Maybe the base go tweaked slightly around this cell?

Advice on setting the base please and best idle timing setting.

Thank you

Lee

[DVS JEZ]

MBT = max break torque, meaning on a dyno keep adding timing till you hit MBT or the knock threshhold which ever comes 1st

[JonnoHR31]

ecu goes into closed loop timing at idle and ignores the ignition map from memory. to set the timing, go monitor, 1 channel, ign timing and set the cas to match whatevers displayed on the h/c

yep, if you reach MBT before it knocks and keep adding timing, power/torque will start to drop off with more timing. so you cant rely on knock alone to tune timing, especially under light load. personally i dont have a dyno or anything like that so just stick to a max of 50 degrees advance at around 4000rpm, less with less rpm obviously.

[leeroy_25]

Thanks or the info guys'' SO I assume once you have set the timing to match the hand commander then you need to alter the map accordingly.. So I guess to start with the ign map needs to read 20/21 degs in the cells that it is using for idle? Then monitor this on the commander (which should now also read 20/21??) and then set the timing to match this with the CAS? I am sure my commander reads different to what the cells in the map say currently? At idle at least. If so why/how?

Thank you

Lee

[JonnoHR31]

ecu goes into closed loop timing at idle and ignores the ignition map from memory.

thats why it doesnt match the map. it uses timing to hold the target idle rpm. if its idling too high the ecu pulls timing to drop it down, idling too low the ecu adds timing etc

after setting the cas so your timing light reads the same as the live timing read out on the h/c under monitor make the 4 cells at the top left of the map (n1, p1. n1, p2. n2, p1 and n2, p2) 20 degrees and leave it at that

or if you send me your map file i can edit it for you

Edited February 8, 2011 by JonnoHR31

[Don Dada]

ecu goes into closed loop timing at idle and ignores the ignition map from memory. to set the timing, go monitor, 1 channel, ign timing and set the cas to match whatevers displayed on the h/c

I could be wrong but the rb26 pfc does not use timing to adjust the idle....well at least the Ljetro. I think this is only for MAP based pfc as it has the option to turn it off and on on under setting 1 ....I would think closed loop better describes afr because with closed loop switched on on the pfc while crusing the afr bounces back and forth to maintain stoich but the ignition timing reads a straight value of whatever cell it is using at the time

Leeroy what cell/cells does it use at idle?

I think whats happening is the the higher value youre seeing is the interpolated value....I'll try to explain..

The cell normally used at idle(on my car) is N1 P2 which shows on the 2nd map as 20* With the ac on it goes to N1 P3 which is also 20* @ 950-1000rpm.

Now N1 by default is 800rpm and N2 is 1200rpm so 1200-800=400.......400/2=200.......200+800=1000 rpm ......so the pfc will use the value in N1 up to ABOUT 1000rpm, then it would start to use the interpolated value meaning, at around half way between the two cells it would calculate an average of the value in the cell its moving from to the cell its going to and use that value

For instance from the 2nd map N1 P2= 20* and N2 P2= 22* so if you look at map tracer and the little box is about half way between these two cells which should be around 1000rpm the timing will be showing 21*

Like wise when moving down the map with increased load or moving diagonal with increased load and rpm the same applies with interpolation

So if your little black box is hovering around the center of these four cells..N1 P2, N1 P3, N2 P2, N2 P3 , it would be normal to see a value like 23* on the hc as it would be interpolating using values from all four cells

I'm not sure about rb30s and the specs for timing but the 26 is 20* at crank from factory so i set it to that and tune from there because technically what ever you add to your base using the cas remember it would not be at idle alone but across the entire map

The 1st map shown it the default datalogit map and the 2nd is the base pfc map

Btw i'm not a professional tuner so this is just my 2c

[paulr33]

for ljetro the timing for rb25 is locked to 15deg regardless of what is on the IGN map values

you then set the cas to 15deg and it should be spot on

for djetro there is the option to enable/dislabe idle-G control under function select

for rb26 timing at idle is locked to 20deg and it ignores whatever is on the ignition map at idle

[Don Dada]

So if your little black box is hovering around the center of these four cells..N1 P2, N1 P3, N2 P2, N2 P3 , it would be normal to see a value like 23* on the hc as it would be interpolating using values from all four cells

My bad but i havent used my hc since i got datalogit so i just realised that map tracer on the hc does not show a gradual movement from one cell to the other like datalogit does....it just jumps to the next cell so you would only see it in one cell at a time but bascially what i described before is what happens so hope you get the picture

What Paul means by "locked" is that if you make any changes to the idle cell on the ign map the pfc will still hold timing at 20* by default, likewise you could turn your cas from now till tommorrow and the pfc will still show 20* at idle

However if you use the temp ign/inj in settings to adjust the ign it holds whatever value you enter......wierd

[JonnoHR31]

its a good feature. in standard form it controls the idle very well, altho pfc's dont seam to do it very well sometimes. it also allows you to enter higher values around idle in the map for better response from idle, without it affecting idle