I love how the only things you bring up are Subaru marketing propaganda and no substantive facts. If they had a fast car, they should have raced it where it could be compared with many other cars as a benchmark. Cars are normally faster than bikes... don’t know why Subaru wasn’t.
But we know what they say about opinions so let’s stick to the technical facts about why it’s a terrible design.
- Boxer engines create a lot of complexity for little/no benefit. For example, there is twice as many cam shafts which mean twice as many actuators for VVT, twice as many head gaskets (which are know to fail and repair requires REMOVING the engine) twice as many cam seals. All of this more or less equates to twice as many problems
- The cylinder is flat meaning getting an even oil distribution is difficult/impossible.
- The turbocharger cannot be located near the exhaust ports meaning you must run a smaller turbine wheel to get decent spool. Smaller turbine wheels lead to higher EGT’s which create a ton of problems (don’t ask me how I know). This is why for a long time, the STI despite having 25% more displacement actually had a smaller turbo than the Evo.
- The exhaust routing makes equal length headers more difficult making twin scroll less/not effective
- The entire engine is cantilevered in front of the front wheels! Mass ahead of the front wheels REDUCES the weight measured at the rear wheels. This is already a problem on front engine cars and Subaru has exacerbated it
- Top mount intercooler. I probably don’t need to say more
- Try changing spark plugs
- Turbocharger plumbing - turbo plumbing is already difficult but when you locate all four cylinders in the four corners of the engine bay, you make it worst and getting perfectly even flow in/out of each one is hard
- Timing belts must be twice as long (which makes stretch an issue) or you must have two
- Basic maintenance on the cylinder heads requires removing the entire engine.
Subaru will tell you “but it lowers the center of gravity” which is true... kind of. The engine is lower but you raise a ton of components higher in doing so and make things complicated. They have never offered any numbers on how much it lowers the CG and that’s because it’s a gimmick. Compare these problems to an I4 like in an Evo and you will see why they make so much more HP with significantly fewer engine problems than a Subaru.
Having said all this, Subaru’s are well made and there is talk of going away from the boxer engine. This would mean better performance, reliability and fuel economy. I’m all for this.
Remember, there is a reason why no one else mass produced boxer engines in front engine configurations.