There are two settings that can be changed through the extension manager:
timtab_badbehavior settings in the EM.
Verbose HTTP request loggingLogs every request
Strict checkingEnables more strict checking and blocks more spam. The downside is, that the risk of false positives is raised. This may lead to blocking of legitimate requests. You should only use this, if regular checking still allows to much spambot requests to reach your site.