Hi dears,
Just sharing here my project, it is a MB C230 SportCoupe V6, I just did an engine swap from the original M272E25 to a M272E35 (V6 NA 3.5L,that was originally from an ML350).

So far everything looks pretty good, initially did a light stage 1 without anything else than limiting the lambda at 0.85, increased the noise tolerance of the knock level recordings, and maxing the airflow restrictor. With only these modifications everything felt way more reactive than before, not based on anything else than buttometer, but I think I was objective.

Now, I made a second version as I will be swapping the manifold to a fixed manifold (from SLK350 R171), BMC air filters, and changing the cats to some magnaflow sport cats I had from a previous project never used.

I'm all open to suggestions, as for me this is just a hobby, my first job was at a tuning company but after a year pivoted to be developer / devops / automation engineer, so I kept it as a hobby for years and did my things mostly by comparison, with damos for patterns, and with other tunes to undestand approaches, this year decided to pay actually a training to understand better the concepts, get better at identifying patterns, and to kick start my journey on reverse engineering which is something I tried a few times and never got the idea on how to approach, now at least I understand a few methods to get to the places I want, to manipulate the code and etc, I think I needed just a kick there.

These are all the modifications I made:

KFKE*: Raised the level +25% (not by percentage actually, but I did it by +10 raw value), I understand that increasing the noise / characteristics tolerance will give me around 3 ~ 4 degrees of tolerance for knock detection
KFKRFKN (Knock retard, accumulative): Reduced the steps from the original -3 degrees to -0.750 as doing this will accumulate smaller steps back when detecting knock
LAMFA (Lambda on driver's wish): Just made the high load section a little richer, originally 0.92 and I moved it to 0.88
KLRLNMXN: Maxed to top, so basically removed this airflow restrictor
KFMIRL (Desired charged, VE): I basically flatted the decrease after the peak on high load, on this map I'm actually not completely sure if the effects will affect on anything on this NA car
KFMLDMX: I understand this one is just for diagnosis to not avoid the ECU detecting something is off, again on this one just increased the high part
KFMIOP (Max engine moment, OptTQ): Raised high load on +6%
KFZW* (Timing maps): Advanced the timing between 3 and 1.5 degrees, only at high section

I think my main doubts are around KFMIOP and KFMIRL, like most people does anyways as I've seen around.
So, doubts, on my training I understood that the idea is that to get an actual increase the objective is to to increase VE (KFMIRL) and reduce OptTQ (KFMIOP), as far as axis do not get modified to allow extrapolation do the magic, now if you check on my file I actually increased both, by different %, but I'm 100% honest, the file I'm working on is 100% original as I'm working on an ECU I flashed and virginized when doing the swap, the tune is 80% my work, and on this two particular maps (KFMIOP and KFMIRL) I made by comparison with another tune.

I have not tested this yet on the car as I'm waiting for the manifold to arrive, and will work on those set of physical changes by the end of this year hopefully.

Aside the doubt on KFMIP and KFMIRL, can you share a general opinion / recommendation / correction on the approach?

If you don't care about emissions and efficiency, go for Lambda 0,85 as soon as you tip the pedal
It will give you maximum torque right away.

Watch knock closely. With only 0,75 Degree knock retard per event the knock control reacts more slowly on knock. If heavy knock occurs out of the sudden, it might be too little retard per time.

Could work in moderate temperatures with good octane fuel.
But could blow on a hot day with medium octane.
Or when somehow some oil is entering combustion chamber.

I would raise it again and lower Lambda below 0,85 on spots where knock occurs. Typicaly the engine has one spot for a certain rpm range, depending on mods.

Good luck.

1. You need to start logging instead of making random changes.
2. Doing anything but 1.00 lambda below 2000 rpm is really stupid. It will only result in lots of black soot and horrible fuel consumption.
3. You need to log the axis on the LAMFA map, because how do you know what is 110 or 120?
4. Leave the knock detection maps alone. You have no idea what you are doing - increasing the integrator delta will not give you any more power. You will damage the engine and LOSE power doing it.

The only thing you can change is mixture, timing and camshaft adjustment.
For mixture and cams you need a dyno. This 0.85 suggestion in this thread is retarded, these engines don't make peak power at 0.85.

The only thing you can change without a dyno is timing by adjusting it closer to the knock limit on your fuel (if there is anything to adjust).
So unfuck all the maps you messed up, get a logger that can show you rpm&load and per-cylinder knock retard, and advance the timing until you find the optimal one.

That's it, you're done. Unless you can get to a dyno and then see if there is anything to gain with cams and find the optimal mixture profile.
But we're talking max 5 hp here for a ton of money. I wouldn't bother, and I have my own dyno.

Or just run the stock software, because I guarantee your changes up to this point have made it worse.

VehiCAL logger does not have advanced for your ECU, so that's fairly limited as well.
Better than nothing though.

I suggested 0,85 Lambda for peak torque.
That's what he wants, more omph when hitting the pedal.

No need to call anyone retarded when the goals are unclear.

In my opinion not peak power in first attempt when using the "Popometer" or "buttmeter" approach is used as mentioned.



Back to topic.

Go out and log knocking.
The Daimler with that engine i had access to, had the knock area more in the 3500..4000 rpm area. When i remember correctly 0,82 was what we used there. In the top rpm we went to Lambda 0,92 around for the mentioned peak power.
Car was happy and felt good through the whole rpm range with that approach. First peak torque, then adjusting Lambda for higher rpm. Never went to dyno because we didn't care

No guarantee that anything of those data works well on your car.

Lamfa Axis should be taken care of, correct.

As i'm from Germany, we need to stay at Lambda 1,00 for any load up to about 1800 rpm du to emission tests every two years. That's the point to start lowering Lambda for me, works usually well, not too much smoke

Yeah ok, no bullying needed.

Yes, i tuned that specific MB engine as i said. Lambda 0,85 at peak torque felt best and gave best maf readings there. Thatswhy i replied and suggested it.



I tuned MB NA V8, 0,85 was not best. Leaner needed, just as you said.
Volvo NA engines (5, 6, 8 Cyl Yamaha) work best with 0,85 in mid range too.

No Subaru or NA Alfa so far.


Let's wait what thread creator finds out about peak torque.

Regarding the peak power, it is clear at least for me 0.85 is not for peak power, if theory is fine 1.05 is peak economy and 0.86 is peak power, but that is just a guide, I understand that is a per engine definition and not something universal. I just made it richer on the top end because I only adjusted the top ends, I don't see a reason to adjust the mid to lower section of the car if I'm actually not doing anything interesting in there. And as timing was moved by 3 degrees (base timing, not optimum timing), made it a little richer just there at high load high revs, from 0.92 to 0.85

Don't touch the OEM mixture. It's more than likely not running what is in LAMFA anyway, on WOT it will be BTS depending on ignition angle efficiency.
Only do this if you have a dyno and can see the curve and the differences between the adjustment.

And anyway, don't touch anything before you logged the car stock. If you already have knock at stock timing then advancing it will lose power.

But hey, do whatever you want. I've had lots of these butt engine dyno tunes on my dyno which made less power than stock.
And what is described here - +timing +fuel is 99% of the time exactly what was done.

Yes, but again, without a dyno you can not see if it makes more power or not.
Looking at MAF numbers does not really tell you anything, because adjusting it too far into overlap won't necessarily increase cylinder filling, but sure the MAF number will be higher.