is there any way to tell a visual difference in a s4 and a s5 13bt?

if they are stock motors one would be the mechanical linkage to the throttle body for the OMP, s4 has mechanical and s5 is electric, another easy one is a plastic thermostat housing on a s5 versus a aluminum one on a s4. There are aftermarket housings sold but if the motor is stock thats a quick easy thing to check.



s4 8 blade fan, s5 10 blade fan.



those aare 3 quickies you can easily see.

S5 has the knock sensor holes above the spark plugs.

its crazy how that small problem holds up a days work lol. thanks

On S4, there will be a boss on the center iron near the oil filler neck, facing forward, thats tapped for the knock sensor.