ignition base timing A vs B

bako · 09-10-2012, 02:36 PM

hello everybody!

I was working on my ecu ignition table to get rid of some flkc and fbkc. everything is clear, I have done it. I almost do not see knock correction in log files. but one qqestion is diging my mind: what is difference between A and B tables? I know what base A timing does, but for what reason is there second B table? for low octane fuel? if it's for low octane fuel, I should retard values there even more to be safe... (I always use RON98)

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Paidfor · 09-11-2012, 09:37 AM

The map switches to "B" with the flash block connected, other than that.....idk maybe it goes to B map when knock is detected, not sure about that though.

bako · 09-11-2012, 12:44 PM

anyone can confirm about flashblock?

interesting way to choose between maps without reflash

NSFW · 09-16-2012, 04:55 PM

When's the last time you updated your ECU definition file?

I thought that they were renamed to "cruise" and "non-cruise" now, but I'll admit that I'm not sure.

My LGT has A and B boost tables (target and initial WGDC) but it only uses one of each, and the other is completely unused. Some cars have a cruise/non-cruise parameter that transitions from one set of tables to the other.

Map switching would require changes to the ECU code. There is a custom ROM for some 16-bit ECUs, perhaps including yours... I have a 32-bit ECU so I haven't followed it closely, but you can learn about it here:

http://www.romraider.com/forum/viewforum.php?f=36

t5r · 09-30-2012, 10:45 PM

When I was reflashing, and tuning Suzuki ecu's they had A maps for fuel and ignition. I was able to switch between them by grounding, or un grounding a specific wire going in to the ecu. That was the wires only function. Grounded would be map A for exampe just running on motor, and switch (unground) (switch time aprox 60ms) and your in map B (for a dry shot nos map, more fuel and pulling timing as nos was applied). It worked very seamlessly when configured properly. The early ecus ran the SH7052 chip. I'm shure the Subi ecus have this, but I don't know how to switch between the two. I'm shure somebody out there knows. It would be nice for tuning.

NSFW · 10-01-2012, 06:22 AM

Joining the test-mode connectors (same ones used to reflash) will drop IAM to zero, but I don't know if it will affect which ignition and fueling tables are used.

Try logging the "map switch ratio" parameter and toggling the connectors. If it moves between 1 and 0 then you're onto something. The catch is that in most ROMs the ratio also changes when driving ("cruise" vs "non-cruise"). The tables that govern the aren't included in the open-source ROM definitions but that could probably be addressed if there's interest.

Bizko1288 · 11-04-2012, 08:40 AM

Is it general rule of thumb to just match the two tables? I noticed it was like that from the factory, so I just always did.

By "flash block connecter", I am assuming you mean the green test mode one. Connecting the test mode connector throws the car into "limp mode", correct? If connecting that switches to B, should timing be more conservative on the B table?

lukeskywrx · 11-04-2012, 12:22 PM

The flash blocks are used by the 16bit ecus only

ppayer38 · 11-14-2012, 09:41 PM

Ill bump this as I'm intrested in the results if anybody has tested it

09-10-2012, 02:36 PM	#1
bako Scooby Specialist Member#: 226211 Join Date: Oct 2009 Location: Europe Vehicle: 2002 impreza WRX JDM blue	ignition base timing A vs B hello everybody! I was working on my ecu ignition table to get rid of some flkc and fbkc. everything is clear, I have done it. I almost do not see knock correction in log files. but one qqestion is diging my mind: what is difference between A and B tables? I know what base A timing does, but for what reason is there second B table? for low octane fuel? if it's for low octane fuel, I should retard values there even more to be safe... (I always use RON98) * Registered users of the site do not see these ads.

09-30-2012, 10:45 PM	#5
t5r Scooby Newbie Member#: 173959 Join Date: Mar 2008 Location: NC Vehicle: 04 STI SILVER	Map switching When I was reflashing, and tuning Suzuki ecu's they had A maps for fuel and ignition. I was able to switch between them by grounding, or un grounding a specific wire going in to the ecu. That was the wires only function. Grounded would be map A for exampe just running on motor, and switch (unground) (switch time aprox 60ms) and your in map B (for a dry shot nos map, more fuel and pulling timing as nos was applied). It worked very seamlessly when configured properly. The early ecus ran the SH7052 chip. I'm shure the Subi ecus have this, but I don't know how to switch between the two. I'm shure somebody out there knows. It would be nice for tuning.

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09-11-2012, 09:37 AM	#2
Paidfor Scooby Specialist Member#: 267815 Join Date: Dec 2010 Chapter/Region: South East Location: 04STi JAVA Vehicle: EVO Woudve been Cheaper!!!!!	The map switches to "B" with the flash block connected, other than that.....idk maybe it goes to B map when knock is detected, not sure about that though.

09-11-2012, 12:44 PM	#3
bako Scooby Specialist Member#: 226211 Join Date: Oct 2009 Location: Europe Vehicle: 2002 impreza WRX JDM blue	anyone can confirm about flashblock? interesting way to choose between maps without reflash

09-16-2012, 04:55 PM	#4
NSFW Scooby Guru Member#: 140444 Join Date: Feb 2007 Chapter/Region: NWIC Location: Near Seattle, WA Vehicle: 05 Stage Free LGT ATP 3076, 6MT, AVO FMIC	When's the last time you updated your ECU definition file? I thought that they were renamed to "cruise" and "non-cruise" now, but I'll admit that I'm not sure. My LGT has A and B boost tables (target and initial WGDC) but it only uses one of each, and the other is completely unused. Some cars have a cruise/non-cruise parameter that transitions from one set of tables to the other. Map switching would require changes to the ECU code. There is a custom ROM for some 16-bit ECUs, perhaps including yours... I have a 32-bit ECU so I haven't followed it closely, but you can learn about it here: http://www.romraider.com/forum/viewforum.php?f=36

10-01-2012, 06:22 AM	#6
NSFW Scooby Guru Member#: 140444 Join Date: Feb 2007 Chapter/Region: NWIC Location: Near Seattle, WA Vehicle: 05 Stage Free LGT ATP 3076, 6MT, AVO FMIC	Joining the test-mode connectors (same ones used to reflash) will drop IAM to zero, but I don't know if it will affect which ignition and fueling tables are used. Try logging the "map switch ratio" parameter and toggling the connectors. If it moves between 1 and 0 then you're onto something. The catch is that in most ROMs the ratio also changes when driving ("cruise" vs "non-cruise"). The tables that govern the aren't included in the open-source ROM definitions but that could probably be addressed if there's interest.

11-04-2012, 08:40 AM	#7
Bizko1288 Scooby Newbie Member#: 151260 Join Date: Jun 2007 Chapter/Region: MAIC Location: Annapolis, MD Vehicle: 2005 Sti 423whp/422wtq on 93	Is it general rule of thumb to just match the two tables? I noticed it was like that from the factory, so I just always did. By "flash block connecter", I am assuming you mean the green test mode one. Connecting the test mode connector throws the car into "limp mode", correct? If connecting that switches to B, should timing be more conservative on the B table?

11-04-2012, 12:22 PM	#8
lukeskywrx Scooby Specialist Member#: 59837 Join Date: Apr 2004 Chapter/Region: SWIC Location: Arizona Vehicle: 2004 Spec-C Type RA What MAF? -Speed Density!	The flash blocks are used by the 16bit ecus only

11-14-2012, 09:41 PM	#9
ppayer38 Scooby Specialist Member#: 234407 Join Date: Jan 2010 Chapter/Region: MAIC Location: Smithfield, VA Vehicle: 04 Self-tooned STi	Ill bump this as I'm intrested in the results if anybody has tested it