A4SGD10C ROM has lower resolution maps than 900C

A4SGD10C ROM has lower resolution maps than 900C

Postby Kha0S » Fri Jan 27, 2006 3:10 pm

Interesting notes on ROM images...

The A4SG900C ROM on my ECU runs substantially higher resolution maps than the A4SGD10C ROM.

For instance:
900C Main Ignition: 16x18
D10C Main Ignition: 16x16

900C Ignition Correction: 16x18
D10C Ignition Correction: 13x16

900C Low Det Fuel: 16x18
D10C Low Det Fuel: 15x16

900C Low Det Fuel: 16x18
D10C Low Det Fuel: 14x18

In most cases, high load figures (4.27 g/cyl charge column, and potentially the 4.11 g/cyl column) and high RPM (7200, 7400, 7600 rows) are simply not included in the maps.

Any ideas why a later version of the ROM would have lower resolution maps than the earlier one?

/Andrew
Kha0S
 
Posts: 106
Joined: Tue Jan 11, 2005 12:30 pm
Location: MY02 USDM WRX / Nashua, NH

Postby Jon [in CT] » Fri Jan 27, 2006 6:11 pm

You probably know that your A4SG900C CalID is the base (i.e. oldest) ROM for the 2002 WRX. According to http://forums.openecu.org/download.php?id=214, the ROM with CalID A4SGD10C was created to fix a "Pinging at high rpm (6000)" problem with the 2002 US WRX.

Somewhere along the line, someone decided to simplify some maps by removing cells that were unreachable due to their high load or rpm indices. It is bizarre, though, that the ignition correction map's dimensions don't match those of the main ignition map.
Jon [in CT]
 
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Postby Kha0S » Mon Jan 30, 2006 12:20 pm

Jon [in CT] wrote:You probably know that your A4SG900C CalID is the base (i.e. oldest) ROM for the 2002 WRX. According to http://forums.openecu.org/download.php?id=214, the ROM with CalID A4SGD10C was created to fix a "Pinging at high rpm (6000)" problem with the 2002 US WRX.


Indeed. I never got the upgraded CalID on my car (I was out of warranty long before new calibrations were being offered. I've been considering reflashing to one of the more recent CalIDs and using that as a base for my tuning, but after finding the reduced resolution, I've decided against it.

Jon [in CT] wrote:Somewhere along the line, someone decided to simplify some maps by removing cells that were unreachable due to their high load or rpm indices. It is bizarre, though, that the ignition correction map's dimensions don't match those of the main ignition map.


Perhaps... the extra 4.27 g/cyl column is very useful, however, if you're running any kind of increased boost... I'm seeing loads as high as 4.7 g/cyl on cold, dry nights. The high RPM indices are certainly understandable, but if you rescale the map to use a lower max RPM, it leaves you a lot of extra rows that you can utilize in the turbo spool time to optimize driveability.

I certainly agree with you on how odd it is that the dimensions don't match. It really threw me for a loop.

/Andrew
Kha0S
 
Posts: 106
Joined: Tue Jan 11, 2005 12:30 pm
Location: MY02 USDM WRX / Nashua, NH


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