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Cold Map Interpolation Tuning

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Old Jun 9, 2010, 07:52 PM
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Cold Map Interpolation Tuning

Hi All,

I have hit an interesting "thing" in the ECU - but a bit of background first:

As we know the ECU has MANY MANY maps, some of these maps are in pairs, one for COLD and one for HOT, the ECU then interpolates between the COLD map and the HOT map based on a percentage defined in an interpolation table.

I am finding that many of these tables - in particular the Throttle tables (more on that later) have a bit of a crappy interpolation:



This means that at 77C the ECU will use 94% of the HOT table and 6% of the COLD table when making a decision.

Given that my car sits at anywhere between 76C and 85C I think that's a bit crapola.

So here is the question, do we either:
a) modify the cold maps and leave the interpolation table stock?
b) modify the interpolation to make 75C give 100%, and leave the cold maps stock?

The situation is a bit more complicated by the fact that THIS PARTICULAR interpolation table is shared amongst "Throttle Requested Torque", "Throttle Maps", "AirFlow maps" and "MIVEC Intake" maps. So obviously modifying this particular interpolator table will have larger ramifications, but none that are negative... AFAIK

Thoughts?

Discuss

Cheers
D.
Old Jun 9, 2010, 08:03 PM
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Wouldn't making 77c 100% work just fine. 76c would be 99.2%. The ECU would round that up to 100%. 75c would be 99% after rounding.
Old Jun 9, 2010, 08:38 PM
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yeah...

as long as the difference between the two maps (cold and hot) isn't large (ie 400 vs 420 NOT 50 vs 500) then 94% is really a bee's dick difference anyways...
Old Jun 9, 2010, 11:08 PM
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ok I think I found out my real issue which prompted the research into this thread.

I had the cold/hot Throttle Requested Torque maps incorrectly defined in my XML...

Going to go test the changes later
Old Jun 9, 2010, 11:22 PM
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That would do it
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