Is there any reason why a larger MAF is needed for Stage 3 at high altitude?
11-28-2005, 11:29 AM
#1
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Is there any reason why a larger MAF is needed for Stage 3 at high altitude?
My understanding is that MAF sizes are increased to "Scale" the MAF sensor readings for larger airflow so that the sensor limit is not exceeded. Well, I am at 6000' altitude and I have never seen my MAF readings exceed 260 g/s for my stage 3- setup. With an 85mm MAF installed I only see 190 g/s, which with scaling comes out to about 254 g/s with a 1.35 scale factor with the larger MAF. So why do I need a larger MAF if I can only flow 260 g/s at this altitude maximum? Is there any benefit to the larger MAF such as increased volume or should I just stick with the sotck 73mm MAF and stage 3- fueling? TIA
11-28-2005, 11:39 AM
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Don't know why it would... who recommended that? Scaling is only used to keep sensor data
within an operational range(sensor range) so you don't have to reprogram/change the table mappings/transitions on all the load variables.
11-28-2005, 11:47 AM
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Also to be a better match for bigger injectors. Not sure you can pull enough primary fuel
to get WOT AFR where you want it if you increase injector size without decreasing airflow #s.
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11-28-2005, 11:57 AM
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Of course there is a benefit. Maybe you should try 83mm (RS4) instead of 85, though.
No need for 85 at altitude if you're seeing those readings. You should probably increase boost, too.