2002_z28_six_speed
September 9th, 2007, 08:55 PM
Not looking for a war thread. Please only respond if you are tuning on cars! Just how many of you feel this way....
Ever since I have been reading on these sites I have been seeing what I shall call MAF bashers.:bash: People who say the MAF sucks..."Throw that crap out." (I will exclude people who have hit the Grams/Sec limit and not upgraded to a newer floating point OS.)
I was wondering if you can run the MAF (OL only) wouldn't you be able to maintain tighter AFR control compared to SD (OL only)? Aren't these people running on misguided thoughts? Surely MAF isn't there to sit pretty or pass emissions in sports cars.
My point is that we have seen that the SD code wasn't modeled to where the air temp and engine temp can be calibrated linearly as they should because an inactive sensor can get false data There is no variable to tell the computer this. Looks like GM calibrators just dumped in more fuel under conditions that heatsoak could occur and moved on because two models were averaged and one could compensate for it in MAF mode. Plus, the O2 make short term corrects.
MAF is better when calibrated, I say. Look at your open loop fueling table. Maybe the PE Air temp table. Where airtemps rise beyond reasonable ambient temps it adds more fuel under IAT tables resulting in non-linear equations. ECT OL tables feed less fuel, level out, and feed more than the ECT gets hot. It sticks out as incorrect but makes it work. Cooling via enriched AFR doesn't seem likey to me, either!
Ideal gas law says IAT should model linearly with its according effect. ECT should be modeled such, also. Because of errors in the model at which anyone could talk at length about....there is no factor or variable that tells the PCM that heatsoak is occuring, feeding inaccurate data, and to adjust fueling such.
This patchwork doesn't matter to people running CL with O2s keeping it in check. If you where running OL and had the MAF then it can see the REAL heatsoak of the aircharge not the surrounding enviroment. If this was biased then the patchwork doesn't matter so much. Even less with CL applied.
I was thinking about how the IAT sensor sucks because it is a non-powered/inactive sensor. Enviromental factors effect it. Then, I thought what would be better? An active/powered sensor. Airplanes use stuff like that to see temperature and airspeed. Why graft something like that to correct the SD model when it would end up exactly like the MAF installed in our vehicles!? Plus, the MAF can calucalte the grams/second. GASP! GM engineers realised you can't model the system correctly with SD only if the O2s fail. Maybe the corrections required more sensors and increased computational time; proved unmeritable.
What if the ambient airtemp really is 150F instead of an artifical 150F? When you can't know the sensor has false data you have to program to protect even if it destroys performance. At that point, why not just upgrade to MAF?
In summmary, so why does everyone bash the MAF so vigilantly?? MAF haters! Well, I say they are wrong. I know SD can correct. I don't think it can be as flexable under all OL conditions, though. I have seen this.
The MAF is heated itself and immune to heatsoak issues because it works in reverse. Cooling, not looking for heat. Heatsoak is backround noise and the SNR is favourable under the hybrid-offset bias system.
Ever since I have been reading on these sites I have been seeing what I shall call MAF bashers.:bash: People who say the MAF sucks..."Throw that crap out." (I will exclude people who have hit the Grams/Sec limit and not upgraded to a newer floating point OS.)
I was wondering if you can run the MAF (OL only) wouldn't you be able to maintain tighter AFR control compared to SD (OL only)? Aren't these people running on misguided thoughts? Surely MAF isn't there to sit pretty or pass emissions in sports cars.
My point is that we have seen that the SD code wasn't modeled to where the air temp and engine temp can be calibrated linearly as they should because an inactive sensor can get false data There is no variable to tell the computer this. Looks like GM calibrators just dumped in more fuel under conditions that heatsoak could occur and moved on because two models were averaged and one could compensate for it in MAF mode. Plus, the O2 make short term corrects.
MAF is better when calibrated, I say. Look at your open loop fueling table. Maybe the PE Air temp table. Where airtemps rise beyond reasonable ambient temps it adds more fuel under IAT tables resulting in non-linear equations. ECT OL tables feed less fuel, level out, and feed more than the ECT gets hot. It sticks out as incorrect but makes it work. Cooling via enriched AFR doesn't seem likey to me, either!
Ideal gas law says IAT should model linearly with its according effect. ECT should be modeled such, also. Because of errors in the model at which anyone could talk at length about....there is no factor or variable that tells the PCM that heatsoak is occuring, feeding inaccurate data, and to adjust fueling such.
This patchwork doesn't matter to people running CL with O2s keeping it in check. If you where running OL and had the MAF then it can see the REAL heatsoak of the aircharge not the surrounding enviroment. If this was biased then the patchwork doesn't matter so much. Even less with CL applied.
I was thinking about how the IAT sensor sucks because it is a non-powered/inactive sensor. Enviromental factors effect it. Then, I thought what would be better? An active/powered sensor. Airplanes use stuff like that to see temperature and airspeed. Why graft something like that to correct the SD model when it would end up exactly like the MAF installed in our vehicles!? Plus, the MAF can calucalte the grams/second. GASP! GM engineers realised you can't model the system correctly with SD only if the O2s fail. Maybe the corrections required more sensors and increased computational time; proved unmeritable.
What if the ambient airtemp really is 150F instead of an artifical 150F? When you can't know the sensor has false data you have to program to protect even if it destroys performance. At that point, why not just upgrade to MAF?
In summmary, so why does everyone bash the MAF so vigilantly?? MAF haters! Well, I say they are wrong. I know SD can correct. I don't think it can be as flexable under all OL conditions, though. I have seen this.
The MAF is heated itself and immune to heatsoak issues because it works in reverse. Cooling, not looking for heat. Heatsoak is backround noise and the SNR is favourable under the hybrid-offset bias system.