99 PCM, Convert To 0411 OS?

[Mikey 97Z M6]

I have a 97 Camaro that has been LS swapped for many years and I have used my EFIlive on it to change things here and there. Like many of you, this car has recently evolved to the point of exceeding the flow capabilities of an 85mm MAF sensor (built NA LS7). That being said, I'm guessing my options are either a Speed Density tune, or switch to an LS7 MAF. My buddy owns a Mustang dyno and helps me out with tuning on occasion. He's not exactly crazy about tuning with SD and I'm not completely sold on SD either. He thought there was a way to convert the operating system in my current 99 gen III pcm to a 0411 operating system. This way I could use the LS7 MAF, at least this is what he told me.

I guess I have three questions:

1. Can my current PCM's OS be converted to the newer 0411 OS?

2. If so, is it possible to use the LS7 MAF with the 0411 OS?

3. Is this a practical way to do this or is there an easier method, short of swapping to an actual 0411 pcm and acquiring another license?

Any help or advice is greatly appreciated.

Mike

[joecar]

Hi Mike,

NA LS7 airflow does not exceed 512 g/s so you should be able to use your current OS.


1. Your 1999 PCM is part number 9354896 and supports OS's that run on part number 12200411.

2. Yes. You have to build a MAF table and correct it (you also have to build a VE table).

3. The easiest thing to do is install the LS7 MAF and calibrate with the OS you have now.


If you really wanted, you could swap OS to 12212156 (from 2002 F-car with same transmission as your car).

[RADustin]

I would go speed density. You loose a little checks and balances but I've only had great experiences with it so far.

[RADustin]

Also, for what it's worth I have been doing research tonight on the 4896 ecu and it looks identical as the 0411. I run OS 12212156 on a 4896 as well and it works great.

You may look at the features the custom op systems have and choose that route with SD

[Mikey 97Z M6]

Thanks guys.

I checked mine last night and the stock MAF table looks like it only goes to 11,000 hz. Is that enough for a NA LS7 making around 675hp? Not sure how that number correlates to horsepower/rpm/airflow etc.? Anyone know by chance?

I did read somewhere that the 0411 operating system goes up to 12,000 for the MAF.

[joecar]

The stock LS7 tune files have MAF pegged at 512 g/s



675 HP = FuelRate [lb/hr] / BSFC [lb/hr/hp] = FuelRate [lb/hr] / 0.5 [lb/hr/HP]

FuelRate [lb/hr] = 675 HP * 0.5 [lb/hr/HP] = 337.5 lb/hr

AirRate [lb/hr] = AFR * FuelRate = 12.5 * 337.5 = 4219 lb/hr == 4219 * 0.126 == 531 g/s


rats, if you assume BSFC at 0.5 lb/hr/hp, then you're going to exceed the MAF limit slightly...

[joecar]

If BSFC is 0.45 lb/hr/hp then the calculation comes out like this:


675 HP = FuelRate [lb/hr] / BSFC [lb/hr/hp] = FuelRate [lb/hr] / [0.45 lb/hr/HP]

FuelRate [lb/hr] = 675 HP * 0.45 [lb/hr/HP] = 303.75 lb/hr

AirRate [lb/hr] = AFR * FuelRate = 12.5 * 303.75 = 3797 lb/hr == 3797 * 0.126 == 478 g/s


so you barely make it if BSFC was 0.45 lb/hr/hp.

[joecar]

Thanks guys.

I checked mine last night and the stock MAF table looks like it only goes to 11,000 hz. Is that enough for a NA LS7 making around 675hp? Not sure how that number correlates to horsepower/rpm/airflow etc.? Anyone know by chance?

I did read somewhere that the 0411 operating system goes up to 12,000 for the MAF.You might have to try this MAF and see what is the maximum Hz it reports.

[RADustin]

I think you'll need a newer card style MAF and possibly scale the ecu to avoid the 512 limit. If you don't exceed 512 you'll be right there.

[Mikey 97Z M6]

One of the reasons I was asking about the 0411 operating system was that I that thought it had a higher scaling for the MAF table. The plan is to use the card style LS7 MAF.

Joe, when you say try it and see what it reports, does the firmware within the MAF dictate the HZ levels that the pcm sees? Is the operating system 'hard' limiting the ceiling on this or the MAF itself? I'm a little hazy on that subject.

Mike

[RADustin]

I'm wondering if you can change the axis of the table. I will look when I get home. If you can- you can reconfigure the table to go to 15khz which is what I think the LS7 is capable of.

You would loose resolution though in the table as the table size is fixed. I think it would be better to put the LS7 card in a larger tube, and remap the table.

It is looking like you will go past the 512 limit though- which if you do you'll need to scale the tune.