fixed some bucking and dipping...
Originally Posted by GuitsBoy
Whos writeup or method do you use for effective area. Ive never trusted my results even though i keep coming up with the same results.
This works pretty well. However once you get close, you have to apply the theory on an individual cell by cell basis if you have a FAST 90 because the shape of the curve is not identical to stock. Mine was adjusted to so that hot idle was around 30 in cool to cold weather. In the summer it will be higher.
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
my own, ive been doing it for a while. noone really thinks its a good idea. ive done the write ups and i have tune my car with stock and my effecitve area and the table i build had better control over rpms.
log iac step, dynamic airflow, desired idle ariflow. if you see iac step of 78, dynamic is higher, then look in the effective area table, you want to lower the value of 78 if it is there, if it isnt then look for the closest number. then hand smooth the table. if you want, get a cold start scan of that and send it to me with your bin and i can look it over. much easier to explain with data. budchevy358@yahoo.com is my email if you wanna send it. also, as the car warms, the effective area will change due to higher engine temps. so i have had to find the fine line in there where it will run good cold and hot. after today i still get some bucking, but i think that has to do with my evap code im throwing, i am hoping my valve going to the intake is getting stuck or something causing weird **** to happen. all i know is yesterday the car ran great and i didnt get that code
log iac step, dynamic airflow, desired idle ariflow. if you see iac step of 78, dynamic is higher, then look in the effective area table, you want to lower the value of 78 if it is there, if it isnt then look for the closest number. then hand smooth the table. if you want, get a cold start scan of that and send it to me with your bin and i can look it over. much easier to explain with data. budchevy358@yahoo.com is my email if you wanna send it. also, as the car warms, the effective area will change due to higher engine temps. so i have had to find the fine line in there where it will run good cold and hot. after today i still get some bucking, but i think that has to do with my evap code im throwing, i am hoping my valve going to the intake is getting stuck or something causing weird **** to happen. all i know is yesterday the car ran great and i didnt get that code
Hot / cold I doubt changes the effective area
at all. What it does change is the amount of air
needed to hold idle, and the point on the table
that you will be at. I believe desired airflow is
translated across MAP (orifice flow/pressure)
to a desired area, and this table tells it how
many stepper counts that is.
If jacking this table on a stock-TB vehicle makes
a change, it's likely just a crutch for something
else that's lame. I think this table only should be
changing if you changed the IAC passage somehow
or changed how much air bypasses it (hole in the
blade etc.).
Aftermarket TBs are another story.
at all. What it does change is the amount of air
needed to hold idle, and the point on the table
that you will be at. I believe desired airflow is
translated across MAP (orifice flow/pressure)
to a desired area, and this table tells it how
many stepper counts that is.
If jacking this table on a stock-TB vehicle makes
a change, it's likely just a crutch for something
else that's lame. I think this table only should be
changing if you changed the IAC passage somehow
or changed how much air bypasses it (hole in the
blade etc.).
Aftermarket TBs are another story.
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
Originally Posted by jimmyblue
Hot / cold I doubt changes the effective area
at all. What it does change is the amount of air
needed to hold idle, and the point on the table
that you will be at. I believe desired airflow is
translated across MAP (orifice flow/pressure)
to a desired area, and this table tells it how
many stepper counts that is.
If jacking this table on a stock-TB vehicle makes
a change, it's likely just a crutch for something
else that's lame. I think this table only should be
changing if you changed the IAC passage somehow
or changed how much air bypasses it (hole in the
blade etc.).
Aftermarket TBs are another story.
at all. What it does change is the amount of air
needed to hold idle, and the point on the table
that you will be at. I believe desired airflow is
translated across MAP (orifice flow/pressure)
to a desired area, and this table tells it how
many stepper counts that is.
If jacking this table on a stock-TB vehicle makes
a change, it's likely just a crutch for something
else that's lame. I think this table only should be
changing if you changed the IAC passage somehow
or changed how much air bypasses it (hole in the
blade etc.).
Aftermarket TBs are another story.
its just like changing the ve table, you are telling the car it is xx amount efficent (or whatever the hell that table is in lol) and that will calculate fueling for that area. you need to tell the car the proper effective area to get airflow correct. in that case, why dont we leave the VE alone and let the fuel trims make changes? thts what we do for idle, we let the stit and ltit make changes when they shouldnt have to. you in turn falsely tell the computer it needs less airflow. i could be wrong but these are my thoughts on it. with this table dialed in you have to get other tables set up right as well. its not just a one shot deal. major mods call for major changes. i naturally look past the surface to dig deeper. that is how i came across this, along with curiosity from others. if you see me making wrong assumptions please point them out though.
