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      04-25-2015, 01:53 PM   #23
Isaiah5411
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Drives: 2008 Montego Blue 328i E93
Join Date: Oct 2006
Location: Modagascar

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I'm absolutely insane for getting into this discussion, but...I need a distraction today (it's raining, my tune is in , and I've been driving all morning) and, other than working out, thinking about modding cars is the healthiest.

First of all, let me get this straight - our choices of combinations when it comes to headers are:

1) Catless headers (e.g. AA), retaining the secondaries
2) Catless headers, removing the secondaries
3) Catted headers (e.g. AFE), retaining the secondaries
4) Catted headers, removing the secondaries.

Not to jack the thread, but here are some questions (say in a car with 3 stage manifold conversion, Euro airbox, PE and AA tune):

a) Clearly, #2 would yield the most power, right? But by how much over #s 1, 3 and 4?
b) How much less power than the others would you get if you chose #3? In other words, is this a horrible choice if you're looking for some noticeable gains?
c) If you have the PE and you're already concerned about the sound it makes, should any of these even be considered without plans to modify the PE, such as put in a resonator (e.g. Vibrant) or a small race muffler (e.g. Borla) where the straight midpipe is?
d) If smell is a concern (e.g. you have a convertible), is #1 still an option or is #3 really the only choice?

Thanks! Talk amongst yourselves.
__________________
2008 Montego "330i" /3.0 manifold /AA /Eurobox /PE /Alufelgen CS7 /Macht Schnell /Michelin PSS /XPel
"O thou afflicted, tossed with tempest, and not comforted, behold, I will lay thy stones with fair colours, and lay thy foundations with sapphires." (Isaiah 54:11)
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