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Unread 05-06-2006, 06:09 PM   #1
Rich Z
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Join Date: Mar 2006
Location: Crawfordville, FL
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Name : Rich Zuchowski
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Question Exhaust back pressure?

OK, I'm confused yet again. When I was considering which headers to get, there was some talk that getting the 1 7/8 inch header pipes compared to the 1 3/4 inchers would possibly be a step down in performance for a basically stock motor. Something to do about the pipes being too big, which honestly didn't make sense to me based on what I had "learned" years ago. Maybe no longer relevant to newer engines, I suppose.

Then lately someone said that my getting the 3 inch pipes from collector to the catback muffler pipes was possibly a mistake as well because they are "too big" for optimum performance. So I may have gained low end power at the expense of top end power.

But if this is the case, what purpose is served by these electric cutouts I see advertised? Don't they COMPLETELY bypass the exhaust system from right after the headers when activated? Conventional (and possibly outdated) wisdom seems to say that uncapping your headers gives you more horsepower because of the unrestricted exhaust.

So obviously I am hearing two directly conflicting opinions about the effects of exhaust mods, at least on the C5/Z06.

How much back pressure is "good" back pressure, if any at all? Would taking the pipes off of the header collector give you MORE or LESS overall power, or would it be a power band thing where power would be gained in one band of the engine's RPM range at the loss of somewhere else?

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