Originally Posted by TryHard

That's not correct. Turbo on the V2 is related to how long the throttle has been at 100%, not anything to do with RPM.
It is quite possible, that if you have a short turbo engage, and are starting from a low rpm, you will have turbo engaged long before a high rpm is reached. And that's before we even start to talk about boost timing addition, and that no load motor RPM (as your doing by taking the pinion off) will always be higher than what's seen on track.
There isn't really any way to quantify exactly when the turbo kicks in, bar having a full om data logger on the car.

Regards
Ed