Terminology

Guys, since I'm not native English speaker i would like to get some clearance on the word "spool" in terms of turbocharging. What does it exactly mean?

To me it's rpm when turbo comes on boost ( something i red in one of the US magazines long time ago which is very logical to me). But i heard some people using it for rpm when turbo gets to the target boost. Some people say the initial meaing is just a "delay" and not related to any rpm...

So, what's the correct meaning?

Thanks.

You have it right, it's referring to how fast it's spinning - 'spooling up' means to increase rpm and 'come on boost', it may be taken as meaning the delay as it's increasing rpm and producing boost as well. It's one of the ways english can mean different things with the same words, or the same thing with different words.

Other expresions are "lag" which is the delay in reaching peak boost from the first application of the throttle in the normal boost range, and "coming on boost" - when one increases rpm under full throttle to the point where the turbo-charger starts producing positive pressure.

Part of the problem is that the Americans tend to make up things to suit themselves and that has spread to the actual english speaking people.

Thank you very much, Gord.