Honda Car Forum

...difference?

Im not sure what size engine you have. But usually you can tell, Because the small engines have a small exhaust manifold, and if it gains you 15 horse power it would be like at least a %10 increase in power.

not much on the butt dyno, maybe 5-10whp if you're lucky. You might lose some of the bottom end due to scavenging, but the top end will feel a lot better. You may also note a marginal decrease in fuel consumption, as the header will let the motor breathe better. The cold start emissions will increase a tad, but most of my toys are catless so, personally, I'm not terribly concerned with the cold start bits.

most cars don't get a huge gain from a new exhaust manifold(header) unless they have had some work done internally. I would expect somewhere around a 3hp gain.