RomRaider

And a log for the negative 25*. Sorry this was not done with RR logger.

Did anyone test or managed to get this to extreme points?
Where for example with the car in neutral you go WOT then take the foot out and engine nearly shuts down due to lack of advance?

ECU does not retard timing all the time during this. After a certain low RPM threshold, it ramps timing back up. Read the table descriptions in RR for the 'Special Functions' tables. There is something called the 'Intercept' RPM that prevents your theoretical scenario from happening.

ASSuming it's tuned correctly. But you can tune it, yes.

Also look at the logs posted in this thread... They clearly show timing ramping back up as RPM drops.

Yes, that was more less what I was asking . To make a very agressive retard and fuel cut so RPM drop faster ... the "intercept" or idle resume will always keep it runing I know.

Im going to run a 5Kg flywheel so I will also be able to test this soon.

still very interested in this, have seen videos of constant flames coming on a 2.8. (ecu mapping only)

Ok so I'm just a tad bit confused here... Can someone give me a clear description of what to do to induce this situation. I have played with it a bit and haven't gotten my 2.8 on ms412 to do this. But for some weird reason before any mods my 328I did this all day long ?

Well I also tried this on the 2.8 with 41.2 conversion (with a bunch of MS41.1 2.8 maps), and it did not do it as much.

The 41.2 has quicker fuel cut off, and shorter ECU cycles on fueling and ignition retard in comparison to 41.1.

After doing -30 deg ignition on decel it only does at best 3-6 quick crackles after 5000 rpm when letting off WOT. Nothing constant.

I see that the MS41.2 pulls fuel out quickly (greater percentage in fewer ecu cycles), which probably contributes to less rev-hang, and very quick RPM drops.
I like the quick rpm drops, so I don't know if we can have both.


I suppose I can put MS41.1 decel maps in as well. I kept those MS41.2 because I had liked the aggressive rev drops.

Did you raise the RPM that enables fuel on decel? You can reduce all the timing you want during decel but you won't get the pops without fuel.

hah, NOPE.

What do they call it in MS41.2?

-edit-

"Fuel Restore - RPM"

Worthy to note that "Fuel Cut - Hysteresis - ECT Threshold" for MS41.1 ID60 is 61°C, and in MS41.2 ID12 is 120°C... a value it will never be over.

Why?

That was it! We now have very loud (still no muffler on car) exhaust decel farts!

Will have to tune it down, or not.. we'll see how it is with a muffler.


Is this dangerous for catalytic I wonder?

Will probably blow your cats out in a day.

I had figured... it's pretty violent without a muffler. Too bad I didn't film any of it, especially to look for flames.

I will probably flash it back to normal. Good test!

So I went and filmed it under the car with action camera attached to rear sway bar.

No auspuff flammen, and it's too loud for the mic, so it clips and distorts the sound. Enough torture on my cats.

haha yeah, when the ignition was around or below 0* I wasn't a fan. I think I found around 10* was a nice spot. I turned it off though. It quickly got annoying and I wasn't sure how healthy it is for everything (valves, o2 sensors, fuel economy, etc)


There's still some cool stuff left on the table to experiment with in the Decel area. I've been meaning to play with the delay to enter decel mode and increase/decrease it to see how I like it.