A0014

[SSpdDmon]

Furthermore, as tenacious as you are Jeff, I can't wait for you to get a RR because I am sure you will teach me a few things. Call Jerry Lewis, let's get the telethon going for kids without a RR!

:lol: I'll think about it. If my latest round of 100%MAF IFR tuning doesn't pan out in a couple of weeks, I'll definitely be giving it some more thought. As for my MAF (screened SLP 85mm), it's stable at low RPM. Right now, it's richening up about a half point or so down low. But other than that, no real side effects noticed yet.

And thanks guys for keeping an open mind. The hardest part of all of this was fighting my urge to tell myself, "Dumbass...IFR tunes are the devil!" :lol:

[redhardsupra]

IFR tunes are the devil.
for the same reason i could say that 'MAF tunes are the devil' or 'VE tunes are the devil'

i'm saying this only to make a point about tuning very large and complex systems with only 1 or 2 variables is totally ignorant of complexity and dimensionality. I know you're trying to simplify it to such a system, becuase that's something our brains can deal with, but it's just not gonna cut it. airflow depends on temperature, and temperature depends on airflow. that alone forces you to adjust both at the same time. and there's a lot of other stuff coming to play on top of that. until we figure out injector setup 100%, all the rest is complete and utter bullshit, since we figure out airflow from the fuel consumpion.

[SSpdDmon]

Post deleted on account of being dazed and confused at the time.

[redhardsupra]

HUH?! i have no idea how you conclude that, and i've been accused of Reverse Polish Logic many times

[Doc]

I have a HP RPN calculator too.

[SSpdDmon]

HUH?! i have no idea how you conclude that, and i've been accused of Reverse Polish Logic many times

My point was...

I'm running a MAF only tune. The MAF is measuring airflow at a fixed point, right? Once it goes past the MAF, it doesn't just disappear off in a dark corner of the engine. Once it's measured, it's consumed. So, why wouldn't the most important reading be IAT - the temp at which the MAF is measuring airflow?

Like I said earleir, I'm having a hard time making myself understand where my brain was going with that. Twas just a random thought.

Either way, I don't think the temp bias table has much of an effect on my MAF only tune. At least, not that I noticed. I'm thinking it's primarily there for VE calculations.

[redhardsupra]

1. if IAT was all that's necessary then why would there be a BIAS table?
2. temp of aircharge inside of the cylinder is NOT the same as in the intake, even if you're moving quickly, it's still got some ECT component to it.

hit me up on IM sometime, i'll show you some stuff i've been working on, i just got my first round of testing on a E40 done, it's been extremely enlightening.

[SSpdDmon]

1. if IAT was all that's necessary then why would there be a BIAS table?
2. temp of aircharge inside of the cylinder is NOT the same as in the intake, even if you're moving quickly, it's still got some ECT component to it.

hit me up on IM sometime, i'll show you some stuff i've been working on, i just got my first round of testing on a E40 done, it's been extremely enlightening.

IDK if the bias table effects more than the VE table. I've tried my current setup with it zero'd out, with it at stock, and with a custom curve. Neither one seemed to make much of a difference. I agree the air temp changes by the time it gets to the cylinder - how much depending on the rate of airflow. Maybe that's why my 100% MAF tune richens up a point under 1500rpms?? The odd thing is, as soon as I'm above 1600~1700, AFR is right back in line with commanded.

[redhardsupra]

jeff, the fact that your model has errors with specific shapes and in specific spots means it's not a good model. read anything about estimation theory and you'll see it's a textbook example of a bad model. i can explain more if you'd like, but it should be fairly obvious if you look at the distribution of residuals.
send me some of your logs and i'll show you what i'm talking about.


you're right about the bias thing. it shouldnt matter for maf only tunes. however, i believe that the maf/sd hybrid model in the gm computers is there for a reason, and i'm going to work with it, not around it.

[SSpdDmon]

jeff, the fact that your model has errors with specific shapes and in specific spots means it's not a good model. read anything about estimation theory and you'll see it's a textbook example of a bad model. i can explain more if you'd like, but it should be fairly obvious if you look at the distribution of residuals.
send me some of your logs and i'll show you what i'm talking about.


you're right about the bias thing. it shouldnt matter for maf only tunes. however, i believe that the maf/sd hybrid model in the gm computers is there for a reason, and i'm going to work with it, not around it.

I realize this. It's more thinking out loud. Like I said earlier, I was typing it, but not making sense of it. :lol: