Plane too slow?

[KillerEST]

Hello!

I'm kinda new to this forum, I hope that the thread is in the right place... I have a weird problem in IL-2 Sturmovik 1946:

Every plane I fly, seems to go ~25% slower than said in aircraft information. For example; let's take SBD-3. It is said that max speed at 4500 m is 413 km/h. I get only ~300 km/h (I was flying at ~4450 m), with Supercharger in positon 2, radiator open. I know that there is a mixture setting and prop. pitch..Should I try changing them?

// Changing mixture/prop. pitch didn't help.

Thanks
KillerEST