Thorwon

PeteS160 my neighbor gave me a pcm service number 16245305. He said it's from a 97 Malibu 2.4l. I can't find what OS is on it.
Before I try to read it, I thought I would ask if you think this might read it.

jamesr

iTrader: (1)

Pics on the internet make it look like a P01 pcm, so I bet this app might read the thing, but I don't know if there'll be any support for it to write to it. Give it a try and see, it's likely not going to hurt it.

jamesr

iTrader: (1)

I don't have a car to run it in, but I tested this with a bench harness and my VCX Nano. Read great, opened in tunerpro great. Disabled VATS, wrote calibration back successfully and read with HPtuners and verified everything looks good in there. It's a 09354896 PCM (basically a 0411), used TIS2000 to put a 2002 Silverado OS and tune on it with the 12212156 OS. Can't wait to get the multi-bar OS options, flex, and P59 going. I'll see if I can track down some friends with P01 powered swaps and see if I can get them to toss one of these in there and see if it works.

NSFW

Fantatic, I really appreciate the update.

What exactly would it take to give 3-bar support to an OS?
* rescale the MAP sensor
* rescale the MAP axis of the open loop fuel table
* rescale the MAP axis of the timing table
* rescale the MAP axis of the VE table
Am I missing anything critical?

I'd also like to know what it would take to convert an OS to speed-density... I've heard people talk about failing the MAF sensor but that I suspect there's more to it.

(I've got plenty of experience tuning and hacking Subaru, but I'm new to GM.)

jamesr

iTrader: (1)

I think it could be simpler than that really.
-There's already a MAP sensor setting in the OS that you can have it scale to a 3 bar or more (can't remember the max value)

-Timing is based off calculated airflow, so there's not really anythign to change there, though i'm sure if that table could be rescaled it would be awesome. HP Tuners does not rescale it so people end up scaling on their own by fudging the engine cylinder volume, VE table, injector size, etc, to keep it on the table if they want, but if it goes off the table it uses the closest cell so you just dial your timing in on that last row.

Open loop is only critical for out of PE mode I think, it'll go off the PE settings if you trip it instead, or whichever is richer or something or other, not really sure there.

So that leaves the VE table, which definitely needs to be able to put in values over 100 kpa. Technically you could do like the timing and dial all your fuel for max boost in there, but that would be terrible.

The other major thing is a special PE table for boost, so once you get into the postiive pressures you can tell it what AFR to shoot for basically.

As far as Speed density, it runs in speed density mode by default if the MAF fails. I'm not really even sure they do anything special for that except force the MAF to fail on the first error detected, because you still have to force it to fail with the custom OSes or it doesnt work right.

I've got a few PCMs and the ability to flash whatever OSes on them that I want, and a flex fuel turbo car if you need a guinea pig. I don't have the time to get up to speed and help with the actual development right now, but I'd be happy to test stuff out.

truckdoug

iTrader: (25)

so in HP tuners boost-land, there is no boost timing. you just use the last two rows of airflow (g/cyl units I think) for your boost timing...kinda crude but it always works

truckdoug

iTrader: (25)

and most folks prefer to fuel directly from the PE and leave BE alone. I personally have had good results from using the BE table in small turbo set ups (7875 on a 6 liter)

jamesr

iTrader: (1)

That seems crazy to me, seems there's a trade-off either way though. Either you can't use different fueling targets for different boost levels or you can't adjust fueling by rpm under boost.

NSFW

PE and BE both seem like terrible ideas to me. The first code change I want to do is to change the inputs to the fuel table to load and RPM, so it'll work just like the timing table. No need for PE after that, and no need to create BE to support forced induction.

MY_2K_Z

iTrader: (1)

You guys would know better than me but pe and BE work fine for me but if there's a better way I'm open to learning.

NSFW

I'm pretty sure PE and/or BE works for everybody in the LS world.

But, coming from a platform were the fuel table and timing table both have RPM along one side and load across the other side, they both seem like unnecessary complications.

If you want more fuel at X RPM and Y grams, you should be able to just tweak that cell in the fuel table, same as you would for spark advance.

NSFW

In the Subaru world, we'd just change the airflow axis so that it goes as high as we need it to... but we were lucky that Subaru's operating system makes that really easy. The table axis itself is just a simple table, so you can put whatever numbers in it that you want. And each fueling/timing/whatever table has its own axis sub-tables, so you can change the axis of one table without affecting any others. Of course you have to rescale the contents of the table when you do that, but rescaling is not something you do very often.

But, for GM.... it looks like if I change the airflow scaling for the timing table, that will also require rescaling a few other tables, and I don't even know what those tables are for yet, so this isn't something I could actually do any time soon.

jamesr

iTrader: (1)

What other tables do you think you'd need to rescale if you changed just the timing table?

truckdoug

iTrader: (25)

all i know is that it defaults to the richer of the two. some very experienced tuners here say to leave BE alone since it "runs slower calculations" but I haven't experienced that personally.

truckdoug

iTrader: (25)

also there is a hard limit to airflow on these pcm's which is why most of us boosted guys run speed density and just deal with the crude timing table


caveat emptor: i'm 100% regurgitating what i've been told ...im no hex programmer

jamesr

iTrader: (1)

I wouldnt be surprised if that was the case, otherwise SURELY one of the big companies would have made the timing table bigger as well with the VE table.

PeteS160

The airflow limit is due to the frequency of the MAF sensor at higher air flow. The limit that's enforced as the "Hard Cap" isn't the absolute limit of the PCM but your getting pretty close at that point. I've heard of a few methods people have tried to get around the limits but in the end they ended up being more headache then they were worth. A couple of people had an idea that it might be possible to write a patch for the OS that would allow it to use the MAF reading up to a given point and then switch to a speed density tune but it was well outside the capability of anyone messing with the idea. It would take someone like NSFW to make something like that happen though.

truckdoug

iTrader: (25)

yeah i know some of those airflow tables are referenced by the automatic transmission controls in the way of torque inputs....Cesar aka subeone was trying to explain it to me...way over my head

i'm still being a bum on my end btw Pete...just trying to get this damn house sold!

jamesr

iTrader: (1)

Any way to do segment swaps on these bins with TunerPro or other software? Or do I need to create every combination of engine/trans for the 2156 and 603 OSes and pull the bins for everyone? I've already compiled a zip of all 603 OS options for segment swapping. I could do the same for 2156 and pull bins or something.

truckdoug

iTrader: (25)

none that I know of, and when you do load a segment swapped bin often the data is in the wrong places so all the tables have to be populated from scratch.


NSFW: can I bug you about alpha-N tuning via PM? I've been tasked with tuning an E30 that's running microsquirt (and using ITB's with a turbo-yikes)