Correcting ETC Area Scalar

[Kfred 513]

Whats up guys, I just realized that my throttle body scaling has been wrong ever since I put in my DSX 2010 ECM in the car. I am on a stock 2006 throttle body which should be 4,706 mm². My tune has it set to 5,636 mm² which is the newer throttle body. Being simple minded, i want to think i can just multiply any affected tables by .835 which is the ratio between the two. Am i way off with that, or will it work?

The issue isn't a big problem right now, and the car runs fine...but it would be nice if my airflow numbers represented something closer to truth data. Also, if i ever step up to a bigger TB i will need to solve this at that point anyway.

My question is this
-Can i multiply affected tables by .835?
-If so, which tables do i need to change? Anything with an airflow parameter? What about fueling tables?

Tune file attached for reference

[asteggall]

Stock LS7 scalar is 4,725.0000 so just enter that number.

[Kfred 513]

Yeah, that's the easy part. I am trying to avoid fully retuning the car. Right now my tune is based on an incorrect ETC scalar, so i am assuming that all of my airflow tables would be off if i just change the ETC Scalar to the correct number.

[Pekka_Perkeles]

I am on a stock 2006 throttle body which should be 4,706 mm². My tune has it set to 5,636 mm² which is the newer throttle body. Being simple minded, i want to think i can just multiply any affected tables by .835 which is the ratio between the two. Am i way off with that, or will it work?

Go ahead, it won't make any harm to see if it works or not. I would guess it should be pretty close. Just let it idle for a while after flash.

[asteggall]

Yeah, that's the easy part. I am trying to avoid fully retuning the car. Right now my tune is based on an incorrect ETC scalar, so i am assuming that all of my airflow tables would be off if i just change the ETC Scalar to the correct number.

If you are having no issues then it's probably not worth the change. If you do change it it's probably going to effect you fueling very little. Just log and see.

[07GTS]

i believe the area scaler is more for adaptive idle throttle corrections, ive changed mine quite a bit and never had to re do any fueling

[asteggall]

The scaler number tells the ECM how big the TB is minus the amount of area the blade and blade bar take up. So it effects all fueling, but can be tuned around if it wasn't changed.

[07GTS]

yes but fuel isnt adjusted using the throttle blade, if the same TB is used then it dosnt matter what u tell it it flows its actual flow is always the same and thats what fueling is based on, ive gone from stock 4725 to over 7000 and fueling dosnt change

[Kfred 513]

interesting, i may just change it and see what happens, i was under the assumption that my entire tune would have to be scaled....maybe it will help me fix a few issues that I am battling. When i change it i will report back to update the thread.

[mowton]

i believe the area scaler is more for adaptive idle throttle corrections, ive changed mine quite a bit and never had to re do any fueling

In a Drive by Wire (DBW) setup, the TB Scalar tells the PCM what factor to use to develop the TPS% value based on the calculated Adaptive Idle Millimeter Squared results. The Adaptive Idle Function uses the RAF/MFIA, Proportional, Integral, Derivitive idle values and several other idle air adjustments (AC, TC, TF etc) to develop a MM2 opening value equal to the the amount of air needed to control the idle based on the rpm error.

In a Drive By Cable (DBC) setup, the IAC Steps vs Effective area converts the MM2 (Column axis) to IAC Stepper motor count to open and close the IAC pintle in accordance with the Adaptive Idle MM2 calculations.

Will only affect the idle settings and is used to develop accurate TPS%/IAC adaptive idle control.....

Ed M