Search Engine and Relevance

[pjkcards]

The relevance on my forum search is terrible, and I'd like to improve to something similar to the way the vBulletin.com forum is setup (whenever I search there, lots of relevance threads pop up). What are the recommended settings? When I go to vB Options > Search Type, I notice it is in Full text as shown below:
In the relevance options, I have the following settings:
Search Relevance Multi-Word Match Bonus Score: 15
Search Relevance Date Score: 15
Search Relevance Thread Title Score: 5
Search Relevance Post Title Score: 5
Search Relevance Reply Score: .1
Search Relevance Reply Function: none
Search Relevance View Score: .01
Search Relevance Views Function: none
Search Relevance Rating Score: .5
Search Relevance Rating Function: none

I believe these were default. Can I please get suggestions on what I should change to make results more relevant? If I can get the scores that this forum uses or is used most commonly, that would be greatly appreciated.

I read that the scores are irrelevant if I dont use the vB search engine. Am I not using the vB Seach engine? How do I make fulltext results more relevant, as I'd prefer to use that if possible? I just converted over to vB search, and the relevance is still horrible, so I'd like to get back to full search and work on making that more relevant.
Thanks in advance.