It pays to datalog if you mod...
10-18-2011, 09:54 PM
#26
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10-18-2011, 10:48 PM
#27
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2005 E55 AMG
I understand what you are saying but a standalone computer has to be retuned for different weather if being tuned open loop and only referencing a preprogrammed fuel table with no adjustment on the fly ever possible. I couldn't imagine an oem ecu would work like this without a maf since it has to run in a wide variety of climates and elevations. I understand how it could reference boost with the map sensor to adjust fueling based on load, rpm and the present manifold pressure but how does it account for different air density to not run rich or lean? I guess some how they take intake air temp readings and go by cool air is dense and hot air isn't but that still leaves the elevation part. Do you know how they would account for that with the present sensors?
The way it works is if the air is hotter yet the boost stays the same, then the density of the air is lower which means less fuel is needed. If the temps stay the same and the boost goes down then the density of the air is also lower so again, less fuel is required. This is just an example but it's the reason why fuel and timing maps are not linear but rather multidimensional. They not only take into consideration throttle and rpm...they also take map and iat. This makes every precise fueling possible for every scenario imaginable.
10-18-2011, 11:14 PM
#28
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05 White Pano E55, Cadillac CTS-V
I didn't even think about the boost going down since the supercharger can't make up for it like a turbo by just working harder (spinning faster) to still make the set boost so the map sensor could be used seeing lower boost at altitude.
10-18-2011, 11:41 PM
#29
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tell your tuner to add 5-10% more fuel and you will be perfect.
Iv had the same tune on my car and it has adapted to adding more boost and a bigger tb and the target a/f is always the same.I hit around 11.8 at 500whp and 11.8 at 530whp without touching the tune.
Iv had the same tune on my car and it has adapted to adding more boost and a bigger tb and the target a/f is always the same.I hit around 11.8 at 500whp and 11.8 at 530whp without touching the tune.
10-19-2011, 02:13 AM
#30
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2005 E55 AMG
Speed density is pretty awesome...it's just not very fuel efficient compared to MAF systems.
10-19-2011, 08:56 AM
#32
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10-19-2011, 09:15 AM
#33
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