COS3 questions

[RADustin]

Gentlemen,

2 questions on COS3, or COS in general.

Working on tuning my brothers truck. 4.8L(DBW, 1MB), cam, 4L80 right now. Eventually will add a CTS-V blower. We chose OS 12592433, although I don't remember why:Eyecrazy:

Anyways, building up the base tune now to eventually convert to COS3. Will post separately on that...


Questions about COS3-

- I basically started with a L33 5.3 file. Segment swapped in the 4l80 trans segments(trans and trans diag), then ran a 5.3 to 4.8 script to convert the 5.3 portion to 4.8. Anyways, how does the COS take the segment swap? When I full flash the COS, wont it remove the 4L80 segment and put whatever segment is with the COS? After the full flash COS, I only cal flash the data, so I wouldn't be putting the 4L80 segment back in...? I have segment swapped the system segment before from a non-COS file to a COS file and it worked. So just wondering if we have to re-put in the trans manually with a segment swap.

-Will the COS3 run with the MAF still? or does it have to MAFless. I think just because we can, we are thinking about running an LS7 or the stock CTS-V card style MAF with the blower.

-What is the different between COS3 and 5? I have 5 on a 512k in my truck, but I'm still trying to figure out what features will be missing on the COS3? Is it just nitrous?



That's it for now. We'll probably have some more as we go. TIA for any guidance.

[ScarabEpic22]

The COS tutorial (and notes in the Tune tool) simply say to 1) read existing tune and save it, 2) Full flash the base COS file, 3) Cal-only flash file from #1, 4) Re-read controller and save file, 5) use tune from step 4 as base file moving forward.

To me, this means it just updates the Engine OS/Calibration/DTC (at least from what I can tell). I know there are lots of guys running around with COS + 80E swaps, so there has to be a simple way to do it.

I believe the answer to running a MAF is Yes. You can go pure SD, but also should be able to run the MAF (and use it).

[RADustin]

I picked that up as well on the COS tutorial. It'd be great if Paul or Ross the action behind the scenes on what is happening on these initial flashes.

I agree that the only modified segments are the engine ones, as well as I think it expands the checksum area- I think I read that somewhere. Anyways, it probably doesn't matter if you segment swap trans stuff before or after, but better practice to segment swap before.

It's interesting that normally a cal flash doesn't write entire segments, but maybe it does only after a COS full flash and the PCM is left in dead poll? interesting.


good on the MAF. that's what I was hoping. Are you familiar if any card style MAF will work? or only certain ones?

[ScarabEpic22]

You wont be able to segment swap after the upgrade, the COS OS # wont match any GM OS #s so you wont be able to load an alternate file and perform the swap. Do it before. :)

I'd just grab a LS7/3 MAF and go with it. The tough part is updating the IAT portion of the MAF for LS1B PCMs, EFILive doesnt have the scaler so you have to either find someone with the .cax or use another software to do it. Or run a separate IAT sensor.

[RADustin]

You wont be able to segment swap after the upgrade, the COS OS # wont match any GM OS #s so you wont be able to load an alternate file and perform the swap. Do it before. :)

I'd just grab a LS7/3 MAF and go with it. The tough part is updating the IAT portion of the MAF for LS1B PCMs, EFILive doesnt have the scaler so you have to either find someone with the .cax or use another software to do it. Or run a separate IAT sensor.

OK-cool.

I think it will let you segment swap though. I seg swapped the system segment on my corvette file to a camaro one to switch the AC request from +12 input to GND input.

[turbo_bu]

Slightly off topic, but I thought the Corvette AC request was ground and the Camaro was +12 volts.

FWIW, I think somebody posted a CAX the other day that had the IAT scalar in it. I have not tried it yet, but might be something to look into.

[RADustin]

You are probably correct and I'm getting them switched.

Thanks for the heads up on the IAT scaler.

[joecar]

The trans segment swap has to be done before upgrading to the COS.

( BTW: the COS uses an unused part of the trans segment. )

Erik outlined the COS upgrade procedure above... you also have to edit B3647, and populate the new tables (make them in-range).

Yes, COS can use MAF.

Note that in SD (i.e. MAF DTC present), COS retains HO/LO adaptive spark.

COS5 adds Alpha-N (i.e. throttle angle vs rpm VE) (aka TP VE) on top of COS3.




~Moderator~

[RADustin]

so you are saying that the cal flash you do after you full flash on the COS actually flashes on segments and not just data within the segments?

[joecar]

so you are saying that the cal flash you do after you full flash on the COS actually flashes on segments and not just data within the segments?No, the cal flash only writes the data.


The full flash of the empty COS is special, it does not overwrite any existing data in the trans segment, it writes the hidden portions of the engine segment.

[RADustin]

No, the cal flash only writes the data.


The full flash of the empty COS is special, it does not overwrite any existing data in the trans segment, it writes the hidden portions of the engine segment.

That was I was looking for.

Thanks Joe.