в методе buildExcerpts
$sql = "CALL SNIPPETS(
'".$this->sphinx->Escape2($this->sphinx->recodeTo($str))."'
,'".$this->sphinx->Escape($this->sphinx->indexName)."'
,'".$this->sphinx->Escape($this->sphinx->recodeTo($this->sphinx->query." ".$this->sphinx->tags))."'
,500 as limit //вот здесь ставим приемлимое значение
,1 as query_mode
)";