So i have a question, it might be common sense to some people, but i have no experience so i dont know. anyway, my question is that if you have a turbo engine right, and your sitting at a stop light or whatever, and you rev your engine past the boost threshold, and then when it turns green, you shift and take off, is there going to be any "turbo lag?" To me it seems like there wouldnt be, since the turbo should be spooled already, and the rotational mass would keep it from slowing down much in the second it takes to shift, right? I was just thinking about it and that idea popped in my head. Let me know if i'm right or not.

 

Yes.

You can't really build any significant boost without putting a load on the engine, so if you are in neutral revving it up, you aren't gonna build any significant boost.

The second you drop the clutch, the turbo will begin to spool up.

Now, there will be way less lag than if you just floored it from 0 rpm (or idle or whatever)...

Since you are dumping from above the "boost threshold", you will build up to your peak boost very quickly....

But if I think I understand your question, you can't build up boost just revving the engine while in neutral.........however, this does "pre-rev" the engine so that you are in the full-boost rpm range right away, and it will spool up very fast.

 

Oh i see, that makes sense. thanks alot.