tuning ignition

hi, I have a question about why do we lower the ve numbers and retard the timing at very high rpms, what's the point of shifting at high rpms or at redline if we're making less power than mid range rpms, I'm talking about FI engines.

Hi.

1) As we increase engine RPM we also increase engine load which is the mass of air entering each cylinder. Since the volume of cylinder stays the same but it gets more air inside the density of air-fuel mixture is also increasing so is flame speed since molecules of fuel and air get closer to each other. Since flame speed becomes faster you need less ignition timing in order to complete the burn at the same point as before (usually it is when piston positioned 5-20 degrees After TDC depending on particular engine) to get maximum torque and power.

2) Usually power is much bigger at higher RPMs than at mid range RPMs. Although torque curve is declining towards red line power curve is still higher comparing to mid range RPM. Since power is the reason for a car to accelerate you want always to be around maximum power RPM range for fastest acceleration and you need to keep in mind what RPM the engine is going to be at after shifting the gear - usually the shift point is about 10 percent higher than maximum power RPM so you always stay around that RPM range for maximum acceleration...

ok I understand what you're saying but in the course video he showed us a VE table and I noticed that close to redline and full load the VE numbers starts to decrease a little bit which means less air in the combustion chamber which means less fuel and less power, also for an example, I have a mk7 gti stage 3, I notice at very high rpms (close to redline around 6,000 to 7,000 rpms) a loss of power and when I shift to the next gear the car feels alive again.

is this just on FI engines, maybe because the turbo can't keep up at very high rpms?

At red line VE drops but not that much. Less torque is made but the engine makes more revolutions per minute so more work is done over time which is power. So you need to look at this combo- torque at specific RPM to find out power produced. Based on that information you choose your shift points bearing in mind gear ratio of the next gear - it will affect on engine RPM (thus power level) after shifting.

You're confusing torque and power - they're different, if related.