Well, that also depends which direction you're running. Uphill or downhill, the to speed difference would be 3-5mph. I've seen others that reach up to 231 from standing start and speeds in excess of 250 with draft.
I'm tuning one of these myself and and only reaching 225 on the downhill side of the tunnel. If I had SSRX I would be able to do finer tuning of the gears but the key to that elusive speed is in gears 3 through 5..