Bf109 max speed...

[Anders_And]

Sorry guys for an annoying question...
I come from 10 years of Il2 playing and I cant get the bf109E to speed up here in this game...

So what do I do?
Well I start at an airfield and open radiator fully start up the engine and give her full power.. After take off I retract the gear and close raditor slightly to not overheat. Max speed I can accelerate to is ca 390km/h IAS in level flight at sealevel... What am I missing or forgetting?? :/

I realise this question sounds soooo noobish..
cheers