Afm Dilemma

[Jmaac]

Worse driveability, poorer response, less accurate A/F ratios and ignition timing............why would I?

Cheers

Gary

Oh I wouldnt, just asked.

You can also go one afm, two intakes and copy the signal accross the two and scale it

[Guilt-Toy]

Can you help me with a table i can try ? I am using the standard rb25det ramp table with my car, and its got the rb30det.

i noticed the last ramp table is 21321 can i increase that number to get a little more out of it ? or do i have to just decrease the AFM correction ?

I am only reving it to 7000rpm if that helps and i find with the standard ramp table it goes all the way down to line 20 on 25psi on rev point 10 then across 3, then up one line and across 2 then up another line and across 3.

So it maxes out all the way down but then comes back into the map. any ideas? ive got datalogit so i can send you my data file?

At what RPM?

What AFM ramp table are you using?

I can get to 20 on zero boost by changing the ramp table

5.2 volts

Cheers

Gary

[paulr33]

Can you help me with a table i can try ? I am using the standard rb25det ramp table with my car, and its got the rb30det.

i noticed the last ramp table is 21321 can i increase that number to get a little more out of it ? or do i have to just decrease the AFM correction ?

I am only reving it to 7000rpm if that helps and i find with the standard ramp table it goes all the way down to line 20 on 25psi on rev point 10 then across 3, then up one line and across 2 then up another line and across 3.

So it maxes out all the way down but then comes back into the map. any ideas? ive got datalogit so i can send you my data file?

hi GT,

you can use the AFM ramp table to help you do this - each voltage range has a % correction

chaning the number applies correction to the final load CALC which reaches the load number - you can see 21321

so it works a bit like this

LOAD = (AFM V * lookup value from hidden ramp ) * % correction)

so say your afm is 4.0v and on the hidden ramp table in datalogit for 4.2 to 4.4v its got airflow value of 8000

then it will use that work out the "load" calc and then apply correction so say it gives you a final "load" value of 18000 for 4.2v

but on the AFM ramp table (on the hand controller_) you have %80 correct for 4.2v upto 4.8v then it will drop that final load value to say 16000 (lets pretend thats %80 of 18000)

this is how you shift it aroiund on the load axis - boost means nothing as its ljetro so you its purely AFM load and ramp

so in your case find out what AFM voltage its reading when you drop to row 20 (im guessing around 4.8v)

then for the range on SETTING, AIRFLOW (press NEXT TWICE) edit 4.8v correction and change it from (its probably %100) to say %90

this will then apply correction and should bring it back down to say maybe row 18

be careful when doing this - because if you move it to row say 18 and that row has been properly tuned it could have unsafe AFRS" or too much timing etc as its using new load calls - so be careful;

[Guilt-Toy]

yeah i know about the AFM voltage correction... I guess i need to jump on the dyno again before doing anymore testing as its too hard on the street and i need to get my turbo rebuilt before i do any of this.

I need to re-test it because i think its going wayyy past 5volts

Edited February 19, 2008 by Guilt-Toy

[paulr33]

have a read of

http://paulr33.skylinesaustralia.com/docs/...erfc-faq.htm#61

it shows you how the "LOAD" calculations are worked out

once you understand this its easy to understand how the correction % stuff works

and where the FC gets and decides the load values from