what dose it take to swap a 91 13bt into an 86, is there any differece from an s4 to s4 13bt swap?

91 13BT, isn't just a 13bt. I thought 91's come with a 13BTT? I might be wrong, but. a 91 is an FD? is it not?

91 13BT, isn't just a 13bt. I thought 91's come with a 13BTT? I might be wrong, but. a 91 is an FD? is it not?
fds are 93-97 in the usa

Ecu, wiring harness for the s5.

fd's are 93-95

and you need to change the dash too

big pain the the buttocks

Fd has a 13B-RE not a 13BTT :P

IT is not worth the effort to go S5 in an S4 unless you have lots of money to spend on thing. But the S4 rotors are the best of the best. I use them in the RE's that see high boost as they are the strongest of the Mazda rotors.

the fd is the 13b-rew

cosmoes got the 13b-re

or am i wrong

interesting you use the s4 rotors, is it because of compression or somethign

the 13bre and rew are the same motors with the exception of a few slecte parts. But yes, you are correct.
S4 rotors are stronger than the S5's. They take alot more to damage the rotor. The S5's were made to be light so you can rev the engine more, but who needs that with big boost :D