BLM cell boundaries
Thread Starter
Racer
Joined: Jul 2002
Posts: 269
Likes: 0
From: Paris AR, USA
BLM cell boundaries
Could anyone here give me an explanation about how these boundaries for airflow and rpm work? I have airflow boundaries of 13, 21, and 34 g/sec, and RPM boundaries of 1K, 1.2K, and 2K. What would be some reasons one might change them? Say, if you put in a higher stall converter or different gears that might affect the RPM and/or airflow range that the engine operates under: Would that warrant a change?
Just curious and trying to gain a better understanding of how this works!
My car's an '88 3.07 auto. I'm running on a modified ARAP .bin right now, and I have the following mods: ZZ4 cam, ported stock base, runners, and plenum, TB bypass, air pump delete, dual exhaust- no cats, and the GM 12" high stall converter (which seems to brake stall to about 2200)
Thanks for any info
Jason
Just curious and trying to gain a better understanding of how this works!
My car's an '88 3.07 auto. I'm running on a modified ARAP .bin right now, and I have the following mods: ZZ4 cam, ported stock base, runners, and plenum, TB bypass, air pump delete, dual exhaust- no cats, and the GM 12" high stall converter (which seems to brake stall to about 2200)
Thanks for any info
Jason
Drifting
Joined: Mar 2001
Posts: 1,636
Likes: 3
From: Lafayette IN
Re: BLM cell boundaries (needanother1)
Things are probably going to be different since my experience (if you can call it that) is with MAP cars.
The above pic is the number of times each cell was entered while collecting about 14,000 data points. All kinds of driving conditions...merged from a few different scenarios I put my car through. Notice that 5 of the cells were never hit at all. About the only condition it didn't cover was coasting down a 70 degree grade...
Anyhow, my cell 4 gets used a bunch because it is an idle cell for the MAP setup.
The main reason I would change them is this: when conditions change and you shift from one cell to another, the last used BLM of the cell you are now going into is reinstated. Say you were in cell 5 and the BLM was 120, then you went to cell 6 and your BLM was 130. You drop back into cell 5 and immediately, your BLM goes to 120. I am going to go out on a limb and say that if your BLMs are all at 128 all the time, you probably won't benefit from changing the boundaries. You might benefit though if you find your BLMs constant in certain areas...by using those areas as an imagined airflow and RPM combination, you could mold the cells around those.
Good luck. -Matt
The above pic is the number of times each cell was entered while collecting about 14,000 data points. All kinds of driving conditions...merged from a few different scenarios I put my car through. Notice that 5 of the cells were never hit at all. About the only condition it didn't cover was coasting down a 70 degree grade...
Anyhow, my cell 4 gets used a bunch because it is an idle cell for the MAP setup.
The main reason I would change them is this: when conditions change and you shift from one cell to another, the last used BLM of the cell you are now going into is reinstated. Say you were in cell 5 and the BLM was 120, then you went to cell 6 and your BLM was 130. You drop back into cell 5 and immediately, your BLM goes to 120. I am going to go out on a limb and say that if your BLMs are all at 128 all the time, you probably won't benefit from changing the boundaries. You might benefit though if you find your BLMs constant in certain areas...by using those areas as an imagined airflow and RPM combination, you could mold the cells around those.
Good luck. -Matt
