[celek]

Originally Posted by Lonewolf

Any input regarding known engine internal changes over the years with the FA20?
@celek @cf6mech @FT-86 SpeedFactory @FullBlown @Element Tuning @CSG Mike @Evasive Motorsports

I would assume the 2015 FA20DIT has different parts then the FA20 GT86 engine.
This entire post would be a little better with comparison part numbers and even better with measurements and pictures. When the FA20DIT was in R&D they may have located a new manufacture to supply valves cheaper.

Manufactures are always looking for cost savings for more profit.

Where these part numbers are pulled from in the OP I am unsure. I could look to see if they have been superseded. As mentioned above, new supplier, new coating, reengineered? Without comparing side by side its a guess.

If not backwards compatible I will guess FA20DIT WRX part VS FA20 BRZ/FRS part. Which still may be compatible but not according to Subaru

Edited, I am going to guess new source manufacture = new part number