:::RHMT::: Real Home Made Turbo
General Category => Engine Management => Topic started by: patsmx5 on August 24, 2009, 05:27:15 PM
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Should I setup the megasquirt to pull timing at any certain temp? It has that feature, but I have it set to run normal timing up to like 150*F, then it retards a few degrees by 190*F. But of course I never see those temps so it's pointless. Just wondering if I should tune it to work with or without this feature?
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If it's a MAP system hotter air will show the same manifold pressure, but it will be less dense, so the ecu will throw in enough fueling for the colder air at that same pressure (because its tuned for it), which will be excess fuel for the hotter air, thereby slowing your burn and adding evaporative cooling automatically.
Not sure about maf.
The timing you mentioned sounds reasonable.
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for comparison, here are the basic settings in the Crome Gold bins
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv203%2Fryan89crx%2Fcrome.jpg&hash=10df05310fdf4ec17f5d6ba520df2aa32a133324)
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If it's a MAP system hotter air will show the same manifold pressure, but it will be less dense, so the ecu will throw in enough fueling for the colder air at that same pressure (because its tuned for it), which will be excess fuel for the hotter air, thereby slowing your burn and adding evaporative cooling automatically.
Not sure about maf.
The timing you mentioned sounds reasonable.
Some MAF (DSM) are mere flow meters and have an air density aka IAT correction.
MAF cars have IAT ignition corrections.
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for comparison, here are the basic settings in the Crome Gold bins
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv203%2Fryan89crx%2Fcrome.jpg&hash=10df05310fdf4ec17f5d6ba520df2aa32a133324)
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So between 98*F and 134*F it retards between 0 and 3*. I should probably set mine up that way.
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So between 98*F and 134*F it retards between 0 and 3*. I should probably set mine up that way.
no, it starts pulling 3* when the IATs hit 134. so from 134-159 its pulling 3*
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So between 98*F and 134*F it retards between 0 and 3*. I should probably set mine up that way.
no, it starts pulling 3* when the IATs hit 134. so from 134-159 its pulling 3*
Im no tuner, but are you sure about that? I thought it would start pulling timing at 99* and at 134* it had pulled -3
Am I wrong on that? If so Im sure I have some hidden power in mine....lol
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So between 98*F and 134*F it retards between 0 and 3*. I should probably set mine up that way.
no, it starts pulling 3* when the IATs hit 134. so from 134-159 its pulling 3*
Im no tuner, but are you sure about that? I thought it would start pulling timing at 99* and at 134* it had pulled -3
Am I wrong on that? If so Im sure I have some hidden power in mine....lol
i guess i could be wrong as well, i just ASSumed that Crome wasnt smart enough to infer that it needed to start pulling after 99 and max out at 3* when it hit 134.
maybe JD will chime in and enlighten us
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So between 98*F and 134*F it retards between 0 and 3*. I should probably set mine up that way.
no, it starts pulling 3* when the IATs hit 134. so from 134-159 its pulling 3*
Im no tuner, but are you sure about that? I thought it would start pulling timing at 99* and at 134* it had pulled -3
Am I wrong on that? If so Im sure I have some hidden power in mine....lol
i guess i could be wrong as well, i just ASSumed that Crome wasnt smart enough to infer that it needed to start pulling after 99 and max out at 3* when it hit 134.
maybe JD will chime in and enlighten us
Yeah, MS does it the way I mentioned. It just interpolates between values to get the number. Maybe this weekend I'll build some det. cans and try messing with the timing a bit.
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as you get closer to the next IAT table, the ecu will interpolate the fuel/ignition correction.
say you are in a 100 degree table which has 0 timing advance and the next column is 150 with -3 timing advance. at 125* it should be pulling around 1.5. My numbers may be wrong, but thats it in a nutshell.