Ok I feel real stupid asking this but when I look at these charts, I don't know what is going on. There is no legend and there is a blue and red line and I have no clue what is what. I obviously see a correlation with higher RPMs = more HP til a certain RPM but for the other lines that start at 310+HP at 2kRPM and rise until 4kRPMs where it goes back down. What I think I'm reading from this chart is with this exhaust is comparing the HP/Torque of regular vs modded exhaust where modded is stronger in lower RPMs and stock is only decent at higher RPMs in comparison?

 

Blue line is power before, red line is power after. The torque curve is the one that's higher than horsepower BEFORE 5,252 rpm and the horsepower curve is higher AFTER 5,252 rpm(if you look on ANY dyno, they always cross at 5,252rpm). Horsepower is just a way of measuring torque as it relates to engine speed. As torque increases and rpm increases so does horsepower. As torque starts to decrease(on that dyno starting at around 4,000rpm) horsepower continues to increase. That will happen until the increase in engine rpm can no longer compensate for the decrease in torque, and then horsepower starts to drop. Basically whatever they did to that engine caused an increase in power everywhere.

And in case you're curious,

horsepower = torque(at a given engine rpm) x rpm(the same rpm as the torque used for this equation) / 5,252rpm
or hp = tq x rpm / 5,252

And if you REALLY want to learn some stuff http://www.epi-eng.com/piston_engine...and_torque.htm this page has a great article on horsepower and torque, and provides a mathematical proof at the bottom that shows why 5,252rpm is the constant in the hp/tq relationship.

 

That's some great info! I'll be checking out that site!