injector wire harness are different so ill be using S5 TII injectors. my following questions are:

would the S5 TII injectors fit into the S4 TII fuel rails? if not what would i have to do? would there be any clearance issues?

 

they fit

 

You need to use s4 lower grommets. This thread shows the part. https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s4-vs-s5-secondary-injector-differences-839869/

 

i seen that thread,that thread is for the NA intake manifolds. ill be using the S5 TII injectors on a S5 6port with the S4 TII fuel rails.

 

I haven't done this swap, but I think you will be fine. Mazdatrix lists different s4 and s5 (but no turbo/NA) part numbers for the lower spacer, but they seem to be interchangeable.

 

hopefully i dont need to change out the spacer. we all will find out when i do it lol. thanks

but anyones knowledge/help to this thread would be greatly appreciated so keep posting.

 

i belive as long as your use s4 turbo manifolds with s4 fuel rails everything should work out..

 

im looking at doing this also do you need to us the TII wiring harness and ecu