Folks,

So I'm on about my 30th revision of my rom and have been making good progress with a few exceptions. Still working on getting my timing sorted before the final AFR tuning. Also working on my boost control as I'm getting some spikes.

Main thing I am looking for input on is what looks to me like load cell flopping. In other words, it looks like there are several point I commonly hit right on the edge of two load transition point and flop between the two, so what you see in the logs is timing going back and forth between the value in two adjacent cells for a bit. The following is a cap of a 3rd gear pull from 2500 to 7000.



Take a look at this screen shot of my ECU+ logs. I'm sure some will say knock, but you can see the knock voltage in the screen cap. I'm not ruling out knock but with ecu+ it is normally more obvious as you will get a spike over about 2.0V.

I was thinking about shifting the scale on the map a little so that the areas where it seems to flop around are not on a transition zone any longer, so for example if it seems to flop between 7 and 6 degrees advance at 5000 rpm (260 and 280 load) i was thinking of stretching the 260 column to say 270 and 280 to 290.

I would assume the ecu interpolates between cells and makes the change over one it hits the half way point so if you have 7 degrees at 260 and 6 at 280, when you hit 271 it would be running 6 degrees... hope that is not too hard to follow what I am thinking.

Only other thing I can think of is maf smoothing. I'm running the stock intake all the way down to th factory filter. But i have no clue how to smooth out the maf or even if it would help.

 

I know exactly what you are talking about and I've made that same assumption from data logging and watching the timing curve.

You can have no knock during a pull, but with there being a different timing value in EVERY cell the overall timing curve will have slights dips in it as you transition through the RPM scale.

I think that is maybe part of the reason why some tuners fill multipal cells with the same timing number on their maps.

 

Mad_VIII

Your knock voltage shows one thing with the ECU+, my experience shows that even at 1volt, the knock counts are already in the 10-15 range (with evoscan) and that alone WILL bring down your timings.. You will not know whether the ECU is pulling timing unless you know what the ECU itself is seeing (ie the knock count)

Another question I have (which I may have to post in ECU+ forum) is does logging the knock causes noise to be introduced to the ECU hence it is seeing more phantom knocks ..

BTW what boost are you running ? attached is my timing map
your timing seems abit low .. this is done on 93 Oct

 

I run Evoscan and ECU+ in parallel most of the time, I can tell you for certain that knock voltage alone is pretty worthless..

I frequently see voltages over 1.2v without the knock count showing anything..

There is discrimination that goes on, the voltage only shows how much noise is being generated, and spikes in noise show as higher voltages, HOWEVER it doesnt discriminate between engine noise and Knock, the ECU and its knock filters on the other hand look at the knock sensor like a microphone, where there is a spectrum of freqencies and the correct frequencies and intensities are what would trigger the knock count.

Voltage alone can't tell you the whole story, which is why you need to listen to the engine with Det cans if you can.

 

Yeah my timing is a little low. This is with 21-22 psi on the gauge ~19 on the gm 3bar. But If I try to push it any more up top it starts pulling timing.

So, I suppose I will try running evoscan along with ecu+, I wish the dang palm logged boost would show up when you sync the files, but for the time being I should be able to use the laptop for evoscan and the palm for ecu+ and see how things shake out.

 

I'm guessing that your ECU may be seeing knock counts when you tip in (i.e. 2500,100 to 3500,200 range), which is what would cause the initial pulled timing. Try adding some fuel in that range, or going with less timing.

I wouldn't worry about timing flip-flopping between various cells. It will vary from run to run anyways. IMO, tuning isn't about forcing the engine to conform to what you think it should be running at, but allowing it to run at whatever it can sustain safely. So if a timing pattern of something like 5-4-6-3-7 works, it'd be pointless to try to force a pattern of 5-5-5-5-5.

l8r)

 

not to burst your bubbles .. I'm running 25psi ..

I run both inputs to the laptop .. finish the run and compare the rpms .. the good thing is ECU+ reads my wideband and logs faster than evoscan

MJ - totally agree with you .. I can pick up dets on the det cans that even the knock counts doesn't show .. mostly during liftoffs and high load low rpms ..

 

It doesn't have to get a knock, I see load flopping all the time with 0 knock sum. It is pretty normal. That is why some tunners use straight same timing adv numbers for all the high load range. It could be abrupt maf readings or waste gate opening and closing. Also, Stock ECU has a secrete way to change the load value depending on certain conditions. I think there are still too many things to be discovered in Stock ECU to be able to tune like stand alone ECU.

 

Cool Cool,

So I tried to do my normal logging run today with the both evoscan and ecu+, it seems that ecu+palm does not like to record logs with the OBD-II switch turned off, and it has to be to run evoscan.

Loggin the same run as was posted above, i saw only counts of 1 and 2 around the 3K range, I'm fairly sure the reason I dropped to 3* was over running the load column.

I appreciate the feedback guys. I'm thinking I may have a few things going on, one is the boost spikes, still trying to sort that out not sure if I need to tighten or loosen the wastegate actuator so I will try it both ways, also need to clean the intercooler out and do a boost leak test. If I have a leak or the IC is dirty it could be causing high iat's leading to knock resulting in having to run lower timing than what most seem to be able to run.

I also need to get my tuna pro knock sensor hooked and see if I can hear any knock, if not I may try the 05 knock filters

 

I've got a question:
can someone post up a concurrent screenshot of a pull showing evoscan's knocksum output and ecu+'s knock voltage synced up "side by side"?

I don't have the evoscan software and don't know if it's worth it to see "real" knock. Also, does anyone know that the evoscan software is most definately reading knock as the ecu sees it? Does the ecu really see it in "counts" or is that just a more convenient way for us to interpret it? My motor is almost always in the 1.2 volt range even cruising, I have cams, etc. It's always been a grey area in deciding where real knock is w/ the voltage. My guess thus far has been to keep voltage under 1.85V (except for lift of course). I think a comparison of knock sum and voltage would help greatly.

 

I'm still trying to understand how one determines what load cell they're in. This is a big mystery to me, still. With 2 different fuel maps and 6 different timing maps on the EVO 9 it makes no sense.

 

On the VIII it is easy to figure which load cell your in just by looking at your timing curve and finding that vaule on the timing map. Then its just a matter of playing connect the dots.

I'd guess the same procedure can be used on the IX's...

 

This was posted before by the tunner in socal.
Basically you have 3 high octane map and 3 low octane maps in evo 9 and it is used like below. so most of the time you are in high octane map 2.

 

... as long as the ECU isn't detecting any knock and you don't have the same values in adjacent cells.

If you use EvoScan, I'd recommend using the AFR target to determine what load cells you're running in. This way, knock isn't an issue(as long as the octane number stays high).

 

How can you use AFR when your actual AFR rarely if ever corresponds with the AFR you set in ECUFlash?