The following calculator can be used to calculate the header dimensions best suited to your combination. The input terms are below: Bore/Stroke is given in inches . Exhaust Valve Opening Point is given in degrees before bottom dead center (BBDC). Entered values should be greater than 0. Calculation of exhaust system. This guide shows several principals for making a exhaust system. Main differences are; do you want torque or top end power? As an example in these calculations, I use my 1776 cc Volkswagen engine, it sends a whopping 130 Hp at 5.800 rpm. That results in 1/8 mile in 9.7 sec. And 0 to 100 km/h in 9 sec.

Calculate Exhaust Header Length: Maximum Horsepower Output. Tuning the exhaust system can be an important component in achieving maximum power when optimizing the performance of an engine for racing or dyno shootouts.