Tune by Statistics - VemsTune

[BigD]

Thanks Mattias. The upper cells aren't in use yet as I'm trying to get the engine working as well as I can naturally aspirated.

The problem is that during the tuning session, I only seemed to hit some cells under fuel cut. So it would suggest I richen it by 38 points with a variance of 1.7. It's not until I clamp the lambda value that it starts being closer to MLV but there are still those 8s and 10s. I guess what I'm really getting at is, why can't VT take all the things into account that MLV seems to, or am I just using it wrong?

Also, is it possible to add some intelligence to the way VEMS works with lambda values? I had a few misfires due to being too rich. I have an AEM UEGO installed for my AFR gauge (and also as a backup sensor/info source) and when this happens, it seems to ignore the ultra lean values if the trend before that was to super rich - it pegs at 10.0, it's min reading, until it gets a reading in its range, while VEMS reads 18.9 and tries to correct as such.

[gunni]

Let say you have a "50" in one cell, the numbers above and below that in the rpm column will be very close to that.
So you should be able to look at the logs yourself and figure out the change required, always after changing two values smooth out the map so that between cells you are sure are right.

for instance if you hit dead on at 4500rpm and 80kpa then you´ll know that the value there will be very close to right.

It shouldn´t take more then 30min of driving to get a fuel map 95% there. It´s also very much practice.

I don´t feel you should be using auto tune unless the map is 95% there and your just trying to get it very accurate.
Also as mentioned don´t trust any software when it´s suggesting extreme amounts, just calculate it yourself or do an estimate based
on the values in nearby cells.

[Sprocket]

^^^

as above, rough out the VE map manualy using the logs where there are large differences, then smooth out the map in 3D, then use the auto tune to fine tune the map toi get you to around +-5%. afterwards set rich and lean limits to 5%


If you are getting rich missfire, you really need to manualy tune the map in that area acordingly.

Alternatively use a dyno and use the 3D tuning facility and hot keys. Take about 30min to get the map done everywhere

[BigD]

Thanks guys. Yeah I learned that the hard way unfortunately. I went out the first time after roughing in the map and doing some quick tests around the block. I can't drive it around too long because it's loud and, well obviously not street legal. I went on the track and it was quite good except for one hiccup. I come back to the pits, run it through MLV and it tells me to add a pile of fuel in a few places - I thought I was almost melting my engine or something with such a lean area. But it was a misfire fooling it into thinking it's ultra lean. Only after going out again and realizing it's worse, and seeing my AEM show 10s I started changing it by hand.

Now I turned ego down to 1%, turned up the EGT correction (which was at 650c and 20% fuel by default - my ecu was determined to drown my engine lol), now I think I have a map that's close to reality (the one in the earlier post was an intermediate, I've evened out the values). Time for more track time!

It's my first standalone experience, it's been a ton of fun but the learning curve is humbling.

[Pet]

Hi guys, I am a bit frustrated about Vemstune stability. I've tried last stable version (09-07), Tuning by statistic - I made log, then (with connected ecu) run Tuning by statistic - crash. I had converted log to CSV, run MLV, tune VE table and then want to import VE table back to Vemstune. The 1st import was ok, then 2nd attempt no - both VE axis were corrupted - VT restart didn't help. I really don't know how to use VT for VE tuning in praxis. Another thing is how terribly slow is VT Log viewer (I have Dell D430 2x1.33Ghz Core2Duo, 2GB ram, it's not enough ) it's soo laggy, (I can make some video record and show it).It's nice to have antialiased lines, but more important is speed and usability IMHO. MLV is absolutely without any problems and very fast. Anyway VT is still improving, I know it, but I think, the VE tuning/logging capabilities should be on the first place..... Thanks.

[GintsK]

Vemstune can export msq file in right format just once. Any further export is corrupted: MLV reads it, but VT - not. Then simply restart Vestune and you can do it again.
Developers wrote it is solved. Probably included in last nightly version.

Anything better with tuning by statistics? Is there some improvements since beggininig of year?

Gints.