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Downpipe Size for Twins

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Old Jun 12, 2010 | 09:48 AM
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Default Downpipe Size for Twins

I've searched and searched with no luck, so this is my next stab at getting my Q answered.

Trying to finish up my twin kit....finally...dragging this out into a 2 year project...*sigh*....Anyway, I'm trying to figure up what size of downpipe I need to use.

I have a 408 with twin 67's and my plan is to use dual 3" off the turbos and merge into a 4" before going through the K member. I like the way this setup looks, but it is not doing a step up after the pipes merge.



Hence my question, does it need to step up to a 4" or if I keep it 3", how much of a restriction will it be?

Thx,

Cody B.
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