Supercharged VT 355 afm tuning

[shane1]

anyone know what the MAX MAF air rate vs rpm table does?

[delcowizzid]

shameless cut and paste LOL
There is a table of Maximum Airflow VS RPM. This table will become apparent when you are running a MAF system with large displacement engine, which will use large amounts of air at lower RPM than anticipated. You will find that the engine will always scan and show a specific gms/sec even if you determine that you should be using more. If you find yourself in this case, you can increase the entries (usually the upper entries) to avoid ‘pegging the needle’. It’s not commonly known exactly what purpose this table serves (the development engineers obviously know); there are theories that it prevents large engine modifications; or that it serves to help prevent false air readings/fueling calcs based on throttle transients/plenum filling.

[Holden202T]

injectors and fuel pump are big enough I assume ?

[shane1]

It has more than enough fuel to do the job making 300rwkw at half throttle and 4500rpm.i can get 9:1 afr at 4000 it just stops calculating past that.
A quick search of these forums and the web seems to come up with this same problem on the VT .No one seems to have a good answer. Im assuming the max air maf tables can be given a good bump but im still confused as to how it is limiting the measurement. if you go by the table maf max table numbers in the tune it shouldnt even get that far? If all else fails ill just put a bigger airflow meter in and rescale everything, but this airflow meter is more than capable its just software holding it back. the problem is your nearly tuning the whole engine in the last few cells as all the lower cells are unusable.

[shane1]

Delcowizard wouldnt you just max that whole table out if its only a total limiter??much the same as a torque limiting table?

[The1]

which delphi maf part? are the sensor wires clean?

Check to see if the MAF your using is one ive tested and is a genuine item. Check the last few pages of the enhanced PDF

http://pcmhacking.net/forums/viewtopic.php?f=27&t=2518

If the maf is ok then grab the MAF adjustment spreadsheet from enhanced thread above and try increasing the airflow to give it more fuel where you need it.

[The1]

Max Mass Air Rate Vs RPM Table is actually just for torque management.

[shane1]

ok well ive spent all morning on this have tried a lot of things still can get it to work.
If you bump the max maf air tables up for some reason it drops all the spark from the engine ?? instead of the commanded 20 degrees it gives 2?? if you put the table back it gives full spark??
it does increase the fuel slightly but still leans out. The airflow meter is still climbing untill the spark drops out causing a missfire. in both cases the actual calculated g/s is maxed at 153 (the number isnot correct as i cannot get tunerpro to give sensible adx data so im using old EFI live v4.but it still stops on that number in both cases even tho one has a max hz of 11000 and the other 11500.Has anyone ACTUALLY had sucess with the VTV8 using the extended software or is it all bench based??
With the non enhanced tune the /s pegs at 4095 at 10000hz.
in all cases once the g/s maxes out the inj duty cycles drop dramatically.(from 7ms to 4)
I can only assume that there is a hidden torque management table or something that once the software sees what it thinks is max airflow then it bails out .
Open to ideas.
Also anyone have a tunerpro vtv8 adx that works?? Or is there a setting that im missing to make it read correctly as i have data but its all incorrect

[shane1]

just had a bit more of a look and think and i think the issue is that the custom code isnt working as the max numbers correlate to the original 256g/s .and so in effect its still a std tune .

[The1]

are you using the current version of enhanced with it's adx and xdf, sounds like your using just a standard adx which will report the maf airflow wrong.

That doesn't make sense the maf Frequency reading is direct from the sensor itself, the program has no effect on it's reading if your getting 10,000hz with one and more with another then obviously the tune is different eg spark or fuel etc and making more airflow.

The MAX Air rate has not been tested, i havn't looked into it but you shouldn't need to mess with any of the torque management as that is all it is, if you have the traction control etc disabled then it should not be affecting anything, i would say that table is incorrectly defined. I have removed it for the time being from the current version.

The MAF G/S vs Hz has been tested with the current version on the bench all the way to 16226hz @ 510g/s and the injector pulse time follows it. As you say it has not been tested in a vehicle yet but i cannot see any issues. All previous versions than the current were labeled beta.

With 10 models of code to support i hope you can understand the progress rate and testing takes a long time and with only 1 person coding in very little spare time. I try as much as possible to test in vehicle but is very difficult. The Bench setup i use has everything connected and i cover all items variables as best as possible.

As per my previous post we need more information, we cannot help if there is no information, delphi part numbers, log files, wideband readings would all aide.