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Old 02-04-2013, 12:44 PM   #1005
OrbitalEllipses
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Quote:
Originally Posted by Dimman View Post
We can start with what the engine ECU needs to get information about fuel requirements. It needs an airflow reference (the MAF) and a combustion efficiency reference (the O2 sensor). Both of which are reading averages. But on an UEL header it is not scavenging equally on both banks. So if you need 12.5:1 AFR for best power on a UEL one bank may be at 12:1 and the other at 13:1.

To the UEL fans, ask yourselves if you have ever seen an UEL intake manifold...
Stock Subaru intake manifolds have unequal length runners...or at least the older cast aluminum manifolds did.
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