i was wondering if there was any difference between the 20b twin setup and 13b twin setup, if so can it be used on a 13b from a fd?

 

no

 

no, as in no difference or no as can not be used?

 

Can't be done

 

One is 2 rotor- other is 3 rotors..

Unless you are asking about the 20B turbo cartridges fit into the FD twin housings? <~~ is that what you ment to ask?

 

Had looked into this at one point but never followed through. ONE of the 20B twin turbos is a little larger than the 13B REW Twins.

Had considred trying to acquire two of the 20B turbo cartridges and see if they would fit in the 13B turbine housings... but ended up just putting a single in.