Need help adding to XDF

[96HawkCnvt]

So I'm trying to help a young man out with his '89 Chev pickup. He built a 377 CID for it and we are getting a code 33. From what I've read, this is to be expected with a built engine. Anyway, I have done some searching & identified that I need to change the "Max MAP for setting code 33" (this is a 1227747 ecm). I know that it is at $539 and I've got it added to the XDF but I'm not certain what equation to use in the conversion tab when editing. How can I determine for this or any other item that I might want to add to the definition file?

Thanks!

[robertisaar]

assuming it's an 8-bit value:

(X*.369) + 10.354

is what i always use for MAP based equations.

[96HawkCnvt]

assuming it's an 8-bit value:

(X*.369) + 10.354

is what i always use for MAP based equations.

Thanks & that equation comes up with what seems like a reasonable number (67.9 kPa) on a stock bin file. But I would really appreciate a quick summary of how you came up with this equation. Or if you can just point me to some sort of tutorial on this that would be great.

One thing that confuses me is that whomever wrote the original XDF, used different equations for various items showing MAP value. For example:

"Brst Knock Det Rate-MAP Thres"
Uses equation: 0.625000 * X + 0.000000

"DFCO MAP threshold (O/L)"
Uses equation: 0.915700 * X + 0.000000

"DFCO Lower MAP thres"
Uses equation: 1.662500 * X + 0.000000

"DFCO Upper MAP thres"
Uses equation: 0.531250 * X + 0.000000

All of these are shown as 8 bit. So I know that I'm just not understanding but if someone can help explain I'd really appreciate it. Thanks for any further help.

Todd

[robertisaar]

those values may have come out through somebody's hack or they could have pulled them out of anywhere, but if it's working correctly, i see no reason to second-guess it.

i got my equation through looking at a metric DANG!-ton of datastreams and all of the equations it gives point to that being a correct MAP conversion.