Spark threshold and knock

[gunni]

Where the lambda is different between gears is the RPM, MAP, PW, TPSacc, Vbatt, Gammae, Gammaair all the same,
i.e is the ECU doing exactly the same thing?

You can upload the logs to a website for people to download. Also put your msq file with it.
There may be some compenastion function not proberly tuned between the different conditions in each gear.

Without seeing the logs and msq it´s harder to assume the problems occuring causing a missfire.

[AVP]

here is a download link for the .rar file of the msq and the excel file of the datalog.

please let me know if you can see something that i dont!

also my email is: [email protected]. I would be happy if you could tell me if i need to make a change

thanks

vasilis

[gunni]

I can tell you what I see and that is no link 

[AVP]

oops!! forgot to to do the copy/paste...

i will try and send you the rar on your email.

[Sprockets]

Offtopic: can someone tell me in few words the difference between VE table and Lambda target table?

The VE table is just that, it's a map of the engines Volumetric Efficiency, or how well the engine is breathing  The Lambda map is what you alter to get the desired AF ratio at that particular site.  The VE map should be tuned so EGO correction is doing very little, or nothing at all. (Read a few posts by dnb, he's spent a lot of time analysing and tuning his VE table).

Back to the original post, that published VE table doesnt look right to me, seems as if EGO is having to work overtime which is never a good thing.  EGO should only be there as a small tweak, it should never be used to cover a bad mapping job, a 15% swing is rather large.  Spend some time looking at the logs and tweak the VE accordingly.  Also, if you are only using up to the 10x range, consider altering the req fuel to get greater resolution.

-Gavin

[AVP]

Thanks Gavin,

how can you tell if the VE map is wrong?

with EGO off i tuned the engine up to 1.5bar at least only with the VE map and datalogs. The only part of the map that has been done with less accuracy is the high boost high rpm,and that is because there is no available road to do that tuning around.Even so, on datalogs of 4th and 5th gears up to 6500-7500rpm the VE map is correct.

I could alter the reg_fuel for better resolution as you say.That is always an option.

[Sprockets]

The VE table isn't wrong, it just looks rather coarse/unrefined, and I think a lot of other  enrichments have been masking the true VE table which has tripped me a fair few times before now   This is why gunni is so interested in the log to see the gamma variables (total corrections) as obviously these are altering between a slow sped accel run (6th gear) to a high speed accel run.  The accel enrichment being the biggest culprit of all!  This is why having dyno time is a real good thing, can hold a steady load for a while to ensure everything has settled then give the engine what it wants (MBT, right fuel).  Once thats done, i tend to handle the transient with road tuning.  Once you get to the high load portions tho, I still extrapolate the known values, as even I won't hold an engine at 2bar boost at 6000rpm to map lol.

Try and publish the rar file tho, I think the vems.hu file uploader is still running.  I've been amazed with how you've handled and documented this project so far, be nice to get you closer with the calibration

-Gavin

[AVP]

many thanks,

i will try and post the rar file.im not at home comp. at the moment so i cannot post the file.

I always think the accel. enrichments have much to do with it,but i could never think how that would effect the map that much far after the pedal has been pressed.

what i mean by that is,that if i understand correctly,the enrichment and the settings of it,have to do with how fast you press the gas pedal and how hard.But they only last for the amount of sec you have specified. I get those engine roughness quite far away in time and revs from the moment that i go WOT.So i would think that accel. enrichment shouldnt have been a problem.(in theory)

When i go WOT on 3d from 2500rpm i get a roughness on 6000rpm for example, because of lamda being possibly less than 0.70.Now the accel.enrichment should have ended by then.That happens at about 260pka cause the other problem i have is that i cannot get VEMS to control adequetly the boost valve on the audi.I have tried many things,but on lower gears it just cannot hold boost on high rpm.It only holds it better on higher gears.

On 6th gear,although i go wot on 2500 or 2700rpm,it quickly rises boost but just as it passes through the 250kpa region,it stumbles a bit and as it crosses it,its alright again. I hear no knock on that region of any sort. When i reduced the lamda and VE bins,it went better.

[AVP]

http://rapidshare.com/files/262984293/a80avant.rar.html

here is the download link

[gunni]

Offtopic: can someone tell me in few words the difference between VE table and Lambda target table?

Also, if you are only using up to the 10x range, consider altering the req fuel to get greater resolution.

-Gavin

I like using Map multiplication as that does a great deal of background interpolation that you don´t have to worry about.
But that´s just me. Having a bigger range of numbers doesn´t make the tuning better because the vems is interpolation on so many levels that when the cells are right then no matter where between cells or floating around the rpm and map are they will be spot on.
This happens when the VE map is smooth and has a obvious 3d look and feel to it.
I have no problem tuning NA cars with MAP multiplication and only a 5x15 portion of the map.

[AVP]

have you seen the map now?

[AVP]

after further testing and listening, i get now no weird sounds from the engine,but after having reduced the spark i get higher EGTs now much easier!!

i get into a dangerous area around 5000rpm. when running on 0.74 to 0.73lamda on that region.

Do you think it is wise to get the spark a bit higher,or just increase the fueling a bit more?

[gunni]

You have got to stop thinking about EGT´s as #1.

High EGT´s don´t mean anything bad to the engine. AT ALL....

If your getting higher EGT´s because of retarded ignition that is 100% totally normal, Also 300kpa pressure is not like it´s normal or anything, it´s quite high actually, so to assume that you´ll not have problems with 300kpa pressure in the low rpm band is childish,

Just retard the ignition to be safe, richen up the fuel and leave it at that.
If you must fine tune for MBT and max power you´ll have to take it to a dyno, EGT readings will not help you one bit.

[AVP]

ok!
i will take your word for it.

i only need someone with more knowledge than me to fine tune the engine on a dyno now.

But since im going to be having new parts next year,ill leave it for then!

[max]

Cliff wrote that tuning ignition (finding MBT) can be also done by finding detonation - once you hear a knock, retard 3 deg and you are good. Isnt this good enough?