As you all know that on almost every turbocharged engine it makes it's peak torque at spoolup, then progressively dies off as it makes its way to redline. Here's the problem: the boost is staying consistent all the way to redline. Why is this a problem?

Whenever an engine is at it's peak torque, the motor is at it's lowest speed for the most amount of manifold pressure. This gives the boost more time to fill the cylinder because the valve is staying open longer, and the piston speed is slow as well. As the engine rpms climb, the piston speeds up and the valve duration shortens. This becomes a problem when the boost remains the same because the air velocity is NOT speeding up with the engine.

Is there a setting on AEM EMS to progressively run more boost with rpm? I think one of the big tuners on here should experiment a little more with progressive boost. If you look at a procharger dyno graph where the boost is exponential with rpms, the torque is flat as **** and the horsepower is an x=y function.

 

That's what big turbos are for mate. Regular turbos won't be able to flow enough to maintain a flat torque curve. But then the big ones that can flow sufficiently will only make that torque higher up in the rev range.

ta dah!

 

Small turbos are even worse because they can't maintain boost to redline. This conversation is for big turbo cars. Even if a big turbo car can hold the same boost to redline the torque still falls off.