That seems to be a totally different question now.
If you are asking "Can I reach 150K daily users" where previously you only had 22K then that is an SEO / increase traffic question.
If you are asking "Why is my most ever users only 8449, but I know that I get 160K unqiue IPs visiting a day" then this is a board setting issue.
The 8449 figure is the peak at anyone timeframe. This timeframe could be something like within the last 15 minutes. So even though you get 150K uniques in a 24hr period the most of them were online (at the same time) during a 15 minute window.
I don't know vbulletin but presumably there is a control panel setting where you can adjust the timeframe used to record the peak visitors. If you set it too long then this increases server load. Set it too low and you will get smaller spike figures.