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Am I just being cheap?

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Old Oct 18, 2012 | 02:08 AM
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99zMD's Avatar
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Default Am I just being cheap?

I am looking to redo my current exhaust set up.

1 3/4 QTP LT's
QTP ORY
LMII

This is what I had on my 346 and it was fine, but last year I dropped in a 408 and really think the 1 3/4's are holding me back. I know that I will be just fine with 2 inch headers, but keep wondering if I can get away with 1 7/8 instead.

Current setup-
Exhaust see above
RPM 408
TFS 215's
Fast 90/90
UD pulley
486rwhp/481ft-lbs

I'd like to hear everyone's thoughts on 1 7/8 headers for this setup and if it will be sufficient. I am not going nitrous or forced induction, this will stay N/A. I will likely upgrade to 235cc heads and a fast 102 setup in the future.
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Old Oct 18, 2012 | 02:23 AM
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There is a calculation for header size versus cu. in. Remember there is volume and velocity, going too big is not better. Look up the calculation and I think you'll find 1 7/8 is more than enough for 408.
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Old Oct 18, 2012 | 02:47 AM
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Maybe my google fu is weak this morning, but I can't find much on header diameter vs ci, just length. If you have a link to something that would be awesome.
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Old Oct 18, 2012 | 04:07 AM
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1 7/8 will be fine. 2 inch with a y pipe setup will most likely not gain you much. Your headers will out flow the exhaust.

Regardless of size, the most gains can be had with a HVMC. Your current headers with a collector swap will probably suffice. But the same collector on 1 7/8 primaries would be better.
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Old Oct 18, 2012 | 04:08 AM
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Also, keep in mind clearance issues with 2 inch primaries.
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Old Oct 18, 2012 | 06:42 AM
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The Y will not be staying when I change out the headers, I will be going with a true dual setup. Any chance of a net power loss by going with a 2 inch header? I'm liking what I'm hearing about the 1 7/8, they will definitely save me some serious money.
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Old Oct 18, 2012 | 07:10 AM
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I doubt you'll lose power, but what little you gain will not be worth the headaches installing them.
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