does open headers add more HP then having an after market exhaust?

i just need a yes or a no.

 

The answer won't just be yes or no. Usually an open exhaust decreases low rpm power and increases top end power. There's a perfect amount of backpressure that makes the most power at a given rpm.

 

Backpressure decreases power. Velocity and length tuning are what you're thinking of.

 

Sport Compact Car had an EG with a B16a. They talked about huge HP and torque gains from low rpms to redline with an open race header.

I had similar results when I did a header, test pipe and 3" exaust on the 240SX that I had. Good solid gains everywhere.

 

try this https://honda-tech.com/forums/tech-misc-15/disadvantages-advantages-open-headers-2570101/

 

Other than a couple of good posts, it's full of old bad myths. The only disadvantage to an open header is that it is wickedly loud.

 

Yes

 

thank you

 

This thread has been argued a million times. The bottom line is nobody can tell you whether or not your combination of parts will make more power with or without an exhaust so anybodies guess is just that - a guess.

 

Why is it a guess when I've seen it confirmed more than once?

 

It depends on the engine, cam profiles, and the header.

 

put it on the dyno. 3 pulles for what, 75 bucks? do one without it, then two with, or whatever. then you be the judge as to how it helps, or doesn't.

 

Best Response, ever.

 

The original poster supplied absolutely zero information about his build. That is why it is a guess.