Evoscan 2.0 allows me to log a variable called Airflow 2-byte MOD, and the regular Airflow. However, at idle the 2-byte mod gives me a value of around 500hz while the other one gives me a much lower value (10hz range in think). I believe this is because i did not mod my ecu (like i did for 2 byte load), but i do not see the point of having a 2 byte airflow...

What is the 2-byte airflow used for, and why?

BTW, i couldn't find anything on the forums about it.

 

1-byte airflow clips at 1600HZ. If you want data beyond that range, then you need to log 2-byte airflow.


Eric

 

Oh ok, thanks a lot!

BTW, do i have to do any mod to be able to log 2-byte airflow? airflow vs. 2 byte airflow are completely different when I log using evoscan. BTW, ecuflash MAF scaling tables only go up to 1600hz. What does the ecu do beyond 1600hz? Extrapolate?

Do i need to read airflow beyong 1600hz if i only wanna rescale my MAF?

Thanks

 

If you want to log 2-byte airflow, you need to modify your ROM in a similar way that you would modify to log 2-byte load or 2-byte RPM. You need to replace two MUT requests with the variables for the 2-byte airflow for your particular ROM.

If you just want to rescale your MAF, you don't have to log 2-byte airflow. At and above the 1600 Hz mark, the last value in the table is used, from what I understand.


Eric

 

ok thanks a lot... I guess i won't be needing the 2-byte airflow then

 

Can anyone point me to the 2-byte Airflow modification thread?

I searched but could not find anything! Thanks!

 

what is the need in logging 2 byte airflow?

 

AFAIK, the higher the airflow the higher the power the car is making. My Evo 9 with a TBE flows in the 1800+ hz range at the top end.

 

There isn't really a "need" for 2-byte airflow other than to find peak power. The airflow curve will flatten out when the engine reaches max HP output, and this will likely be above the 1600 hz cutoff of the basic 1-byte response.

You can also use the airflow curve to see how modifications help or restrict flow to and from the engine.

 

Also to see how irratic an aftermarket intake can make your readings.