Okay, my question is whether or not swapping an n/a 90 ECU into my n/a 86 will change the hp I'm putting out. 1986 FC's put out about 146 horses, and 89-91's put out about 160 n/a. Is it okay to do it. Give me details if anyone knows. Thanks

 

It won't increase your power.. It will probably not run very good if at all.. (error codes). There are some things the S5 (89-91's) have that the S4's don't.



The HP increase was more due to the lighter and higher compression rotors and the different intake design.

 

the ecu connectors are totallly different. even if it could be done the fuel and timing maps are almost the same.



mike