Id like to know best way to tell the two turbos apart I understand the covers are diferent. What's the best way.

 

The E and B denote the compressor cover used. The B cover is slightly smaller than an E. The cover changes the flow characteristics of the turbocharger. A smaller cover will give faster response but will be limited on overall flow volume.

E cover (left) and S cover (right)


B cover

 

E & B covers are very similar, but the B cover uses odd size inlet/oulets

 

most T04Bs are 2.5" inlet 2" outlet, similar to E cover. Unless you're talking about the occasional 2.75" inlet.