oakley6575

iTrader: (5)

Here is a new log. Towards the end of the log, you can see where I got up on the converter from a stop to start getting the WOT fueling in line.

I'm wondering what the difference is between the dynamic cyl airmass vs the calculated cylinder airmass? I'm kind of confused on why my g/cyl calcs are different than what the histograms show. It seems to be exactly double. So if my dynamic cyl air is showing .18 at idle, the spark histogram sits in the .08 field.

When I go WOT, timing is pretty constant at 20. But If you look at my timing tables, where the F is 20 coming from? Thanks boys. Its been a while since I've done any tuning

1969x11

iTrader: (38)

I don't know but maybe it's burst knock...I don't see anything else that would be pulling timing.

smokeshow

iTrader: (16)

Low octane timing, 5200rpm @ 0.64g/cyl=22°. Subtract 2° for 127° IAT = 20°.

oakley6575

iTrader: (5)

The only thing pulling timing is the IAT table. Why would my histograms be telling me it is reading spark from 32 g/cyl when it is really reading from 64 g/cyl? Also I will copy my high octane table to my low table buy why would it only reference the low when there isn't knock present?

oakley6575

iTrader: (5)

The turbo kit is close to being done so I thought I would get my 3 bar OS up and running.

What years did GM stop using the ethanol content sensor and start using the fuel trims as an ethanol indicator? Should I use on of those OS's as my base or will it not work with my 2003 pcm?

subeone

it means your fueling is off. Calc cyl airmass is dependent on your fueling, the pcm approximates how much air is going in based on how many g/sec of fuel you are injecting; disclaimer, g/sec can also be lb/hr, lb/min, g/min, i just gave g/sec unit as an example. If your fueling/fuel injector data is wrong, your torque calculations are wrong, the calculated airmass is wrong, the spark tables will be wrong (to an extent unless you continue with the hack job and adapt to the wrong g/cyl data.)

oakley6575

iTrader: (5)

I'm using stock NNBS injectors and took the data from a 2009 5.3L truck. I used the LS1 to LS3 data converter and pasted the results in my tune just like I did with my 408 with LS3 injectors. What is odd is that dynamic cyl air is exactly double...

subeone

your airflow table could be the trouble. zero out your maf vs hz table and disable your maf and see what the numbers are, then do the opposite and zero out your VE table and run purely on your MAF and see what the predicted airmass is at in comparison to actual metered air. If you are running purely on speed density that could be the reason why your calc air is wrong. So if your afr error is 0% and you checked with a wideband that you are running on the commanded eq ratio always with +- 2% error throughout, then I sincerely have no idea . I am assuming you have the right info in the general tab of the file right? should be 4.8L drop down and about .6 for volume displacement underneath the table selection list

Have a look at marcin's info

HPTuner experiments: Three Airmass Models

oakley6575

iTrader: (5)

Yes, all my general info is correct. The truck is tuned correctly with fueling <2%. I am running an SD tune by the way. I just don't know why my calc airmass is half of my dynamic airmass. Wierd

Anyways, should I just apply the 3 bar OS to my current tune or should I try using the newer tune without an ethanol content sensor. I don't know if it will work correctly. I would like to be able to fill up with E85 when I want but if it won't work like I'm thinking, its no big deal.

subeone

i recall now what is wrong. I had tuned a trans am with the maf disconnected, N/A though, and the max values i had seen in the calculated airmass was .48 or so, but previous to that when the MAF was connected it had read .96 which was exactly double, the car ran like a bat out of hell with the maf off or on BUT i did see that the spark table histogram only displayed half the resolution because the calc airmass was now halved, so at WOT it was near .48 g/cyl and the spark was not correspondent of the scenario, .48 was cruising/ light acceleration values so the spark values in those cells would be much higher and at WOT it would be too high for comfort. So what i did was upgrade to a 2bar OS even though he was NA since the maf had to be physically connected to properly predict airmass but he wanted the maf removed. The 2bar OS developed by hptuners uses several pids to predict airmass without the use of the maf...

and in regards to ethanol, try to get a sensor that readily tells you the % content, since its hard to get actual 85% ethanol, the variability is too high. Do not attempt to tune without a sensor unless you know the concentration will always be 85% ethanol and 15% gasoline, which you can get from certain vendors but not from your regular e85 station. so 3 bar