Bob_Fout said:Hm Aaron, your SOI is 882 RPM. Mine was 904 RPM dead on. Tuning differences?
tasdrouille said:The last picture is of most interest. It shows fuel conversion efficiency, which translates to fuel economy if you will at various start of injection timing and EGR rates.
So best fuel economy for this engine under stated operating parameters would be near 30% EGR rate and SOI timing around 4 BDTC.
If this engine had an EGR delete, best fuel conversion efficiency would happen at roughly 2 ATDC, again at 1500 rpm.
Ahem...*quiet*...imho increasing EGR and advancing timing accordingly over stock is the path to optimum fuel economy.Variant TDI said:So, if I'm reading the graph correctly, leaving the EGR alone (stock) is the path to optimum fuel economy?
so, do I want my specified & actual to match and be at around .5 atdc and my cold start value to be above 3 at the same time? or do I want my specified & actual to be at 2 atdc and my cold start value to be higher because my egr system is gone?Growler said:ok, I have a question about this process..
I checked my car the other day and in basic settings my timing was hovering between the blue & green lines about halfway when warmed up.
I then went to measuring blocks and my specified & actual start were matching like this thread wants them to, but my cold start value was down at like 2.6 or 2.8 (cannot remember exactly)
my question to the masters is this, do I leave this alone or do I want the cold start value to be above 3 somewhere like the picture posted by aNUT?
Don't worry about the cold start value, it doesn't do anything really.Growler said:so, do I want my specified & actual to match and be at around .5 atdc and my cold start value to be above 3 at the same time? or do I want my specified & actual to be at 2 atdc and my cold start value to be higher because my egr system is gone?
My EGR fell off and has since been plugged with an EGT probe a long time ago, but it is set to stock value in VCDS (now)
well, I got home and played with it and will post what I found and what I did...tasdrouille said:Don't worry about the cold start value, it doesn't do anything really.
Since you don't have any EGR anymore, you only have to worry about timing.
Now the question is what do you want? Fuel economy or better response? If you want fuel economy at light loads, like during highway cruising go with 0. If you want better response and better economy at high loads, with an engine that feels it wants to go more, go with 2-3 btdc. This is what I would do if I had no EGR whatsoever.
This is because the basic timing is set in such a way the ECU can't adapt below 1.1. I posted in a previous post about how it works.Growler said:If I tried lowering the value in Adaptation any more, they would stop being the same. and I couldn't ever get the specified & actual to go below 1.1 and be the same. Getting it to be 0.5 ATDC was impossible. lowest I saw was 0.8 BTDC and the actual couldn't match it.
It won't make a world of a difference. Since you don't have any EGR you'll have good fuel economy at low/mid loads. At 3 BTDC you'd have a tad more happy revving engine and better fuel economy at high loads but that's it. You steeled pretty much for the middle ground.My question after all of this is Should I have left it at around 3.0 and 32900 in the adaptation? or did I do a good thing by bringing it down to 1.1?
Mine went the other way I think. 0.2, 0.4, 0.6. Fluxed between them. I will check it this weekend after a nice long drive.BioBob said:Hey Bob:
Thanks for the input!
I'm glad to hear that the Actual Start is not a fixed value.
What was the total range that you "jumped"?