Header question

At what point is it favorable to go with a "tuned" header over an "untuned" one? I realize that someone "chasing" numbers would spend the extra 200 for a set of tuned headers. Has anyone done any testing to see just what power gains there is going to a tuned header over an untuned header?

What do you mean by "tuned"?

Rich

I think he is thinking about primary length ......


when some one says tuned pipe...I always think of two strokes and my little RC cars .... pipes on little cars like that make big impact on track times...but thats a two stroke

In a set of tuned headers the pipe lengths are carefully calculated to enhance exhaust flow in a particular engine RPM range.

"Tuning" of headers can mean a few different things, that's why I asked what HE meant. Length, configuration, diameter, collector length and diameter, etc. are all variables. David Vizard has written some about this in his usual informative style, I will try to find a link to some excerpts.

Here's a start: http://www.superchevy.com/technical/engines_drivetrain/exhaust/0505phr_exh/

Rich

I would think the most important thing in tuning would be air flow. The bends in the headers would contribute to airflow resistance, so unless you could get all of the primary tubes to flow exactly the same I don't see how you could "tune" the headers properly.

Now I haven't read the article yet so maybe I'll change my mind afterward.:)

Nice article. Worth reading.

Kinda hard to be able to work with a 4th gen street car though. Tuning the collector length could be hard if you have to pass inspection.