Audi RS2

[AVP]

With the help of Gunni, i have been datalogging and trying to make the VE table as best as possible so as to use only the Ego correction up to 100-110kpa. Above that it will only be dealt with VE map and accel enrichment. Yesterdays first tests proved to be quite succesfull! I think EGO is really difficult to work on high revs and on full throttle and it may have been leaning my mixture quite a bit for some reason.

anyway, it seems to be better now,and more tests will be done through the week...

[gunni]

I said leave it off above 80kpa.

[AVP]

 

i know you said that, but sometimes when i use cruise control on the car and there is a need to go a slightly elevated road, on steady cruise it goes up to 100kpa and i prefer to have subtle corrections done there. The VE map should be close to correct lamdas anyway there.

Also during cruising at 120-130Km/h im in the 40-90 area and i dont want ego going on and off all the time. Wont that drive it more mad??

[gunni]

It doesn´t go on and off.

It tries to maintain the lambda target. The quality of the VE tuning will the defining factor of how "mad"
the ego is.
I´d expect no more then 2% incorrectness at such loads and the ego control will have no problem correcting that.

[AVP]

ok point taken!

once i have all VE table bins correctly managed, then i can get ego to go lower as well.

[z0tya]

With a good VE table is possible switch off the EGO correction against ambient temperature, battery voltage fluctuation?
There is compensation for these but how perfect, and how much well-tuned??
The mat correction is hardwired in the firmware before 1.1.5x, and we can't get good settings for injector vbatt correction, so the lambda is never fully perfect. Of course the EGO correction set between tight margin:+-5%

[AVP]

well how much are the injectors off depending on battery fluctuations?

all motronics depend on fueling maps to compensate high rev/boost as MAFs are too small and lamdas are narrow band.

[AVP]

i think i have managed it I havent had much luck on testing high revs on high gears,but so far the EGTs and the car itself is running much smoother with the ego off. the VE map was quite on the rich side which would explain the EGO working overtime though

[AVP]

I know that this is a more or less vague question and it has to do with how close you are within the best timing for more torgue line,but i was wondering this.

Say you want to have a limit to the EGTs so that your exhaust manifold and turbo hotside can cope of 920C.

If you use 18deg of advance and 0.76 to 0.74 lamda to keep the temps at around 900-920C, would turning down the timing to 16deg for example make any difference in the EGTs? I mean, would they get lower so that i could actualy lean the mixture and go towards the 0.79lamda?

I have been told, and its been written here as well that the less timing you use, the more the EGTs will get higher. If that is true then does it mean that in order to get the lamda to 0.79 i would have to increase the timing instead of lowering it? (all that of course keeping in mind that the car doesnt knock.)

Am i going crazy??

Obviously the best thing to do is test these things and log them.
I plan to do a test this weekend (weather permitting) on 4th gear pulls with one settings being : high timing + lamda 0.74 and try and see what the power figure will be, and then try and lower the timing to see what happens to the EGT,and try to adjust the lamda as well if possible to see if there is any difference in power figures.

Reason im doing this, is because on the motronic map,as i have mentioned before, i had loads of timing, but on the lamda,on 6th gear the car was extra rich (0.70) and it never gave any problems or issues. However, being MAF related boost, on 4th gear i would get around 0.75-0.76 lamda initially and after that it would go richer as well. However timing there was 20+deg even when hitting 1.9bar of boost.

So im trying to figure out what is best. Big timing values and extra rich OR adjusted timing to a point that you only use 0.80lamda?

[gunni]

If you lower timing you will see higher EGT´s.

The way to tune is .

Try and find MBT and use as little fuel as possible . The possibility of getting MBT at 1.9bar on street fuel is not that good.
So you´ll have to settle with just below knock as safe as possible. That means usually to run overly rich to pick up a few degrees of timing.
But that is not set in stone. It may be that there will be no difference in tendancy to knock if you run 0.8-0.73 lambda. It´s just something that needs to be found by testing.

[AVP]

so basically if im using 0.73 lamda and 18deg of advance to keep from knocking AND keep egts to a level that are acceptable for the manifold and hotside, the way to reduce the egts more would be to increase timing?

[AVP]

right, i think the VE table is much better now. more secure. I wont tamper with the spark table, as it produces good values and no knock, so it will do the job for now.

[gunni]

so basically if im using 0.73 lamda and 18deg of advance to keep from knocking AND keep egts to a level that are acceptable for the manifold and hotside, the way to reduce the egts more would be to increase timing?

You never increase timing above MBT. You tune to MBT and that´s it.

[AVP]

well without any headphones for knock at least now, i will have to guess the MBT

[AVP]

did some runs today with the perfomance box and i noticed that above 6000rpm at 260-275kpa i had to actually reduce the VE table by 2 (from 90-87-88) otherwise the lamda went all the way to 0.70 and lower. Also i increased the spark as well and EGTs were lowered as well,without any problems.

i think it runs better now.

i must refine my excel for the use of the perfomance box. It appears that im doing something wrong...

i have according to that about 570Nm highest torgue around 3600rpm. then i have 500Nm @ 5600rpm, and 400Nm at 6300rpm.

Not bad concidering that the original rs2 has 410Nm as highest point!!