IAC position vs effective area
04-22-2005, 09:58 PM
#61
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I still have some minor adjusting to do. I just re-enabled proportional idle, for ***** and giggles...We'll see how it works tomorrow when the rain stops. The main thing left kicking my *** now is the Fan airflow...If I turn those bitches off I have a perfect idle with a g5x3 cam on 112 lsa in an A4 w/4200 stall 
I can't seem to figure out a solid scientific approach to determining fan airflow adder. It's just been trial and error...I've almost got it now though.
I can't seem to figure out a solid scientific approach to determining fan airflow adder. It's just been trial and error...I've almost got it now though. 
04-22-2005, 11:33 PM
#62
Reworking my RAF as we speak...I need to log some lower temp points, but it was a pretty good amount off. It'll take a few days to get everything in line. Can't wait to be greeted with a nicer, even steadier idle than I already had (at least I hope).
04-22-2005, 11:42 PM
#63
RAF, is that running airflow?
not sure what these last few posts are inreguards to ws6snake eater, you say at 177 in drive its 12.5? im trying to fix some idle issues and will have to be doing more when i do my cam so sorry for all the questions but this is turning out to be a great thread for help, taught me a lot, thanks guys
just explain the steps you are doing now if you dont mind
not sure what these last few posts are inreguards to ws6snake eater, you say at 177 in drive its 12.5? im trying to fix some idle issues and will have to be doing more when i do my cam so sorry for all the questions but this is turning out to be a great thread for help, taught me a lot, thanks guys
just explain the steps you are doing now if you dont mind
04-23-2005, 12:55 PM
#69
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Originally Posted by Another_User
Not exactly. There are a few factors that affect making a base running airflow change:
1) cam
2) throttle set screw (or :shudder: drilling the TB blade hole bigger)
3) idle speed
The base running airflow controls how much the IAC opens at idle, the cam requires you to crack it open further, and raising your idle required you to crack it open further. This will usually put you beyond the IAC's capability to compensate, so you crack the throttle blade with the set screw. This can be used to put you close, but you will often end up with ECTs at which your car will not idle properly. The way to calibrate that is through the base running airflow table. You can adjust it close with your trims (I usually put mine a hair higher than it needs to be), but it worked out best after I did that and then poly smoothed it. I hope that answers your question without completely hijacking the thread.
1) cam
2) throttle set screw (or :shudder: drilling the TB blade hole bigger)
3) idle speed
The base running airflow controls how much the IAC opens at idle, the cam requires you to crack it open further, and raising your idle required you to crack it open further. This will usually put you beyond the IAC's capability to compensate, so you crack the throttle blade with the set screw. This can be used to put you close, but you will often end up with ECTs at which your car will not idle properly. The way to calibrate that is through the base running airflow table. You can adjust it close with your trims (I usually put mine a hair higher than it needs to be), but it worked out best after I did that and then poly smoothed it. I hope that answers your question without completely hijacking the thread.
04-23-2005, 02:05 PM
#71
ok so when i log STIT, LTIT and i get a net number of -.20 lb/min
do i convert that over to gms/sec and then subtract that number from the table?
whats the steps in this really? so i get the right airflow for that table, i guess the RAF table, and then do the effective area or what?
my numbers are -.20 lb/min or less, is that really anything to worry about or no?
do i convert that over to gms/sec and then subtract that number from the table?
whats the steps in this really? so i get the right airflow for that table, i guess the RAF table, and then do the effective area or what?
my numbers are -.20 lb/min or less, is that really anything to worry about or no?
04-23-2005, 02:23 PM
#72
i have an idea, for making the table for effective area, you can just change the table so at certain settings you get the numbers equal, maybe not all the setting but a few points, fit a line to it in excel, use that equation to make the table.
i am now assuming that after this is done you need to work the RAF table which you can look at the changes per ECT and plot that as well to enter the numbers in the talble, i would assume that would be something that could work, im gonna try it out
i am now assuming that after this is done you need to work the RAF table which you can look at the changes per ECT and plot that as well to enter the numbers in the talble, i would assume that would be something that could work, im gonna try it out
04-23-2005, 04:44 PM
#73
dynamic airflow, is that based on what the VE table is set at?
reason i ask is what if i change my table around, would this be throwing off the numbers or no?
i think i have an excel sheet that will calculate this all out with the dynamic airflow numbers, i just hope they stay consistent enough in SD and dont every a lot with temp like the fuel trims do...
reason i ask is what if i change my table around, would this be throwing off the numbers or no?
i think i have an excel sheet that will calculate this all out with the dynamic airflow numbers, i just hope they stay consistent enough in SD and dont every a lot with temp like the fuel trims do...
04-23-2005, 06:05 PM
#74
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Originally Posted by WS6FirebirdTA00
dynamic airflow, is that based on what the VE table is set at?
reason i ask is what if i change my table around, would this be throwing off the numbers or no?
i think i have an excel sheet that will calculate this all out with the dynamic airflow numbers, i just hope they stay consistent enough in SD and dont every a lot with temp like the fuel trims do...
reason i ask is what if i change my table around, would this be throwing off the numbers or no?
i think i have an excel sheet that will calculate this all out with the dynamic airflow numbers, i just hope they stay consistent enough in SD and dont every a lot with temp like the fuel trims do...
04-23-2005, 07:23 PM
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Originally Posted by WS6FirebirdTA00
SD calculated as opposed to? i dont know mcuh about tuning maf tables, thinking about putting a MAF back on, 85mm, which process do you prefer?
1) scale it (multiply by x percent, up or down, affects high airflow more than los airflow)
2) cell shift (I think I am the only person that does this, affects low airflow more than high airflow, can be mixed with scaling with pretty good results)
3) calculate a new table from scratch (I have not had luck with this, trims are not consistent enough for me at low airflows, some people have claimed good luck with this)
04-23-2005, 10:37 PM
#77
well im gonna try and figure somethings out and talk to some of my professors and see if there is some way we could build a better table.
have u tried redhardsupras way??
well i have a few ideas using some curves you would get from logging and im gonna try that out.
have u tried redhardsupras way??
well i have a few ideas using some curves you would get from logging and im gonna try that out.
04-23-2005, 10:45 PM
#78
try my spreadsheet, it really works well. www.allmod.net/hpt i am yet to find a car/setup/person for which it wouldn't work. TXhorns281 has a recent post about SD-VE-MAF stuff where he pretty much confirms what what he came up with and I've implemented is right. scaling and shifting is child's play comparing to what we have it doing. Gimme a holler if you need any help, i'd be more than glad to explain more.
04-24-2005, 06:23 AM
#79
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Originally Posted by WS6snake-eater
Worked well here. Guys you will have to rebuild your RAF table after completing this. In my case, my effective area was so far off, that I actually had to rework the RAF twice LOL...My effective area now starts at 30. 