Search API Solr fulltext search improve results
You're looking to enable 'partial word' search which would allow for matching w800 with w800a. As described in this blog post, Apache Solr has this capacity built in, it just needs to be enabled by adding this line to the Solr Schema that comes with Search API

&lt;filter class="solr.NGramFilterFactory" mingramsize="3" maxgramsize="25"/&gt;


However, pay attention to their caution about performance issues - you want to only enable this capability on a limited field (ex. the title field) rather than a longtext field as it will greatly increase the size of your index and reduce performance.