I've heard people say that they "tuned" their headers to get more power. I was wondering how this was done? How do you tune a bolt on like that

 

I guess no one knows???

 

You can buy tuned headers, which is what ALL headers are normally. Tuned to make power. But no, you can't really 'tune' an aftermarket header besides polishing it. If you had the cash you could pay someone enough to make you a custom header, but that would be $$$$$.

 

the perfect header for your engine would be the runners diameter being the area of both your exhaust valves and runner length is calculated until you get about twice the cylinder volume.

 

i heard that jdm headers have to get the inside wall cut in order to make the most power. don't flame... that's what i heard

 

I think what they mean by tuned is that its custom. I've done some research in that area and came up with this; headers with long and thin runners create more power in the lower and middle range while thicker and shorter runners create power in the mid to upper end.