I think I have a reasonable understanding of forced induction, but one thing I've never been too sure about is how do superchargers and turbos work at part-throttle? All the online resources I've found only talk about full throttle scenarios.

(The rest of this post is just my guess, not fact)
If the throttle plate is used to cause partial restriction, then I guess a boost controller can detect the increase in pressure and use the wastegate to partially bypass the turbine. I imagine you can also detect vacuum downwind of the throttle plate and use that to mechanically actuate a bypass of some sort.

If that's the case, I'm wondering how you guarantee that the throttle plate can withstand the air pressure? Seems like this would be a big issue especially with our drive by wire setup. Can the servo take the extra pressure?

Thanks,
Jeff

 

Full throttle is the only way to drive an FI car.

The throttle plate rotates in the center of the plate so if there is pressure on it, the pressure is equal on both sides resulting in no additional strain on the servo.

 

Thanks. I was thinking that the two halves of the plate would have different amounts of pressure. Basically I was thinking that the direction of the slope of the plate would result in a lopsided pressure distribution as the air is shoveled to one side. Good thing I'm wrong I guess as it's one less thing to worry about for FI.
--
Jeff