Quote:
Originally Posted by NYYFan325
Can you elaborate on WHY to this? Or point me to a thread where you already did?
I ask because my buddy just put these on his 2014 and I was very impressed with them. I was considering them for myself as well, but I keep getting torn between these and a standard longtube design
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Stepped headers are designed to optimize scavenging and create more power and a broader torque curve than standard straight tube headers. The stepped design is acoustically tuned specifically for their application, some math is involved in order to get it right. When the shock wave from the exhaust valve opening travels across the step it reflects back towards the exhaust valve creating a negative pressure. It's like the waves caused by throwing a rock into water, when the waves hit something like the edge of a pool, they reflect back.
When the step(s) are at the correct length for the application, this wave of negative pressure assists scavenging of the next exhaust cycle by pulling it out into the pressure drop created. The negative pressure could be something like 3-5 PSI at the exhaust valve. This is usually at tuned length of either the HP peak rpm of the engine for a drag car, or the mid-range operating rpm of a street or road race car. The Tri-Y uses similar theory but with a different approach. Placement is just as important.