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Old 11-02-2009, 05:32 PM   #5 (permalink)
Frank Lee
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OK this is my WAG but I suspect "backpressure" is not really a factor; they are talking emissions which include cold start and thus the distance from cat and filter to engine is critical for their heating-up phase.

I suppose if it was more involved that merely shuffling the cat and filter around i.e. if they made them different and less free-flowing that could explain it too.

It would be good to know if these measurements and differences are due to cold start or steady state.
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Last edited by Frank Lee; 11-02-2009 at 05:37 PM..
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