DrkPhx

iTrader: (15)

This is for my 98 TA in my sig. I'm running a descreened ZO6 85mm MAF with the 98 PCM. As most know the 98 OS only goes up to 11250hz for the MAF.

I'm consistently maxing the MAF from 80-100% TPS (sometimes even lower). WB is virtually right on compared to commanded AFR (12.85). After a little WOT datalogging today I noticed the MAF actually hit 12220hz in one spot, while the rest of the run was between 11234-11663hz. I've never seen the MAF register that high (12220hz) on my car, but I routinely see it go above 11250hz at WOT. So now I need to consider my options and was looking for some input and suggestions.

Here are some of the options I was thinking about:
1) - Switch to a later year OS
2) - Switch to a 100mm MAF
3) - Switch to Speed Density

Any help and feedback is appreciated.

Benner

iTrader: (2)

If your maxing out your best option to go on from here is a speed density. I'd think you could have it tuned where it still uses the MAF as an assist to the SD tune to help out with normal driving but the SD being the main tuning the car runs on.

LS1-450

iTrader: (33)

I just modified the PE table by estimating the value based on scaling prior to maxing out during WOT.

RedHardSupra

iTrader: (1)

dont look at the frequency, what is the actual airflow you're seeing?

hymey

is it throwing a mil when u max it out, set high fail to 15000 if it is. Once you get to 11250 hz or whatever it gets it will use its last known value for eg 350g/s. If it starts to go lean at say 5500rpm use the pe table to richen it up, you will be on top of peak torque then anyway so it shouldnt need much more fuel. I wouldnt be too concerned about it.

DrkPhx

iTrader: (15)

On that run it was at .96 grams/cylinder. However at the track it will stay above 1.00 with a max of 1.17.

Ryne @ CMS

iTrader: (10)

if your air fuel is staying steady, i wouldnt worry too much, i would set the freq high to like 15K or so. i would suggest going to speed density though that would take care of all issues

foff667

iTrader: (2)

Are you still using the stock 98 pcm? The only reason I ask is because SD on the stock 98 pcm you loose alot of resolution.

BTW you cannot flash in a newer 99+ operating system into a 98 pcm. You would need to swap out the pcm, repin the harness, etc.

RedHardSupra

iTrader: (1)

that's airmass, not airflow. anyway, that's a lot, and given enough rpm that might be hitting the 512g/sec airflow limit.

ya got any logs?

ringram

Yep over 1g/cyl is nice

DrkPhx

iTrader: (15)

foff667 - I'm still using the stock 98 PCM.
RedHardSupra - That's for clarification. For some reason I don't have the MAF airflow rate PID selected. I will add it for the next log.

I ran a quick WOT run today and noticed the WB hit 13.2 right at 7040 and 6885 (shift points) rpms, but was fine in the lower rpms. The MAF hz also went above 12K on the first shift point.

RedHardSupra

iTrader: (1)

you dont need airflow if you got airmass and rpm, that's why i'm asking for logs.