sorry for posting such a basic question...but does it get triggered at a specific RPM or does it work "in the background all the time"?

I understand (from youtube video) the mechanism (i.e. hot exhaust spins turbine which compresses air, etc). But I how should it "feel" like?

 

Hi all....130 views and no one knows how turbo works?

 

Tempted to say "google it" but I'll give you a very simple explanation...

The exhaust from your engine spins a turbine. The more exhaust flow, the faster this turbine spins. Connected to the other end of the shaft that the turbine spins on is another fan called an impeller. It forces more air INTO your engine. When you force in more air, you can also inject more fuel and then you have bigger explosions and more horsepower.

Because the impeller is driven by the turbine which is driven by the exhaust, a couple of things about the turbo become clear:

1) The turbo is always spinning whenever the engine is running because any exhaust flow makes it spin.
2) The more exhaust flow, the faster the (and with more force) the turbine and hence the impeller will spin. This means that the turbo only helps make more power once the engine is turning at higher RPMS.
3) Because of how how exhaust flows, opening up the throttle more will cause more flow and therefore allow the turbo to push more air into the engine.

So, how should it feel? With small throttle openings and at low RPMS, it should feel like a normal engine. When you open the throttle a lot, and the RPMS start to build, the turbo will start to generate "boost" (positive air pressure in the intake, meaning bigger explosions and more HP) and you'll feel the car start to accelerate at a faster rate - almost like it will surge forward.

In our cars with relatively small turbos, this "rush" won't be so pronounced, but you can definitely feel it. If you drive along slowly and then floor the throttle, you'll feel a slight hesitation (like nothing is happening, but what is happening is that the turbo is spinning up to the point that it will generate pressure) and then all of a sudden you'll feel the power "come in".

Make sense?

 

As you accelerate the turbo spins faster and you feel it pull harder and harder the higher the engine load.

Don't confuse RPM for engine load. High RPMs at idle and you won't "feel" the same thing you would feel accelerating

 

Thanks dtfastbear, good explanation. I understand it now.