How to check for knock retarding

[clifftoo]

This may be simple for most, but I was having some issues telling if my car was knock retarding because I was logging and looking at knock sensor. I had to log the individual knock retard per each cylinder.

Please excuse this post if it is too simple but there isn't a huge amount of info about tuning mercedes so I wanted to share this here to be more visible for those just getting into tuning mercedes.

https://www.youtube.com/watch?v=fG7VIC8-2po

[outlaw_50]

Thanks for the video.

You can make a histogram for each "knock retard cyl", use the axis lables as the tables from vcm editor.
Mercedes knock sensors are sensitive you could get -1 to -2 retard but its false knock.

Finally these cars dont take much timing advance without additives especially the biturbos platforms.

[Makeclick]

Hi clifftoo

I have watched your videos from youtube I like what you are doing. Mercedes tuning should be more open.

I have 2014 A45 AMG and did managed to flash it to dead in some point . With Hp turners support we managed to found the issue (they didn't say it). I think there was 100x reflash limiter in the ecu... because i have seen it with some other way . I have almost 300 reflash times and much and much logging... but i am still very noob with the Mercedes. More knowledge from bmw diesels.

Torque management is pain.. I don't still get it. Normalized torque is like theoretical "100%" my car has 600Nm. The car will never go over 80% of engine torque (i don't know why... TCU?). If i change Normalized torque, torque to load table will be out of everything, because it will follow 0-100% of engine torque. I have get best solution by leaving NT 100% to original 600Nm and i only edited torque to load table. But, it can get funky also...


Here is what i did learn.
https://forum.hptuners.com/showthrea...l=1#post666631

So, if you make intake retard and exhaust advanced (less overlap), you will get more pressure -> more engine sound (voltage), more pressure to cylinder -> easier to get knock, if you not change spark (retard).

[clifftoo]

Hi clifftoo

I have watched your videos from youtube I like what you are doing. Mercedes tuning should be more open.

I have 2014 A45 AMG and did managed to flash it to dead in some point . With Hp turners support we managed to found the issue (they didn't say it). I think there was 100x reflash limiter in the ecu... because i have seen it with some other way . I have almost 300 reflash times and much and much logging... but i am still very noob with the Mercedes. More knowledge from bmw diesels.

Torque management is pain.. I don't still get it. Normalized torque is like theoretical "100%" my car has 600Nm. The car will never go over 80% of engine torque (i don't know why... TCU?). If i change Normalized torque, torque to load table will be out of everything, because it will follow 0-100% of engine torque. I have get best solution by leaving NT 100% to original 600Nm and i only edited torque to load table. But, it can get funky also...


Here is what i did learn.
https://forum.hptuners.com/showthrea...l=1#post666631

So, if you make intake retard and exhaust advanced (less overlap), you will get more pressure -> more engine sound (voltage), more pressure to cylinder -> easier to get knock, if you not change spark (retard).

Whoa 100x limit on flashing and the ecu dies?

Torque management is what I am running down now. I was going to start another thread about the internal torque calculation between normalized torque, optimum torque and torque to load.

I believe if u set the equation above what torque your engine is making u get a p061b. e.g. ur car think it is making more torque than it is.

if you are making more torque than the equation of torque to load and optimum torque you get p061a. e.g. your car thinks it is making less torque than it is.

[Makeclick]

Yep . It started to give X7F Negative response code (do not write whore memory if you get this ) i think they did fix it for all Mercedes. HP support was so great, love those guys!

You should start the thread about torque calculations. I have tried to play with that a lot, but it is still a mystery. Easy way to get more power, is by lowering the NT100%... I don't know why, but it is dangerous, because TCU will get wrong torque input. Therefore line pressure can be too low and can lead to clutch damage.

Hmm.. Sound correct. I haven't get p061b, but p061a i can get if i raise the NT100% to 800Nm and try to calculate whole optimum torque, torque to load and torque limiters to match the "new" 100% maximum torque (NT100%)

so, how i think it works
0-600Nm = 0-100% (torque to load table)
0-800Nm = 0-100% so all in torque to load table is wrong. We have to make calculation to the whole table *1,33333 (600Nm*1,33333x=799,998Nm)

It should be correct? Then i lowered torque limiters, because they are much more higher now (limiter based to 0-100% not to Nm [0,75*limiters]). It should go to close to the default NT600Nm, IF i don't want to use that extra torque, but no... It will get very odd. Shifting more aggressively and not like full throttle.

Hope i make even little sense