Hey, so I've been doing some research on these because I don't know much about them, and it's good to know your enemy, right ? But anyway, all I could find are some diagrams and simple explanations about how it works, but I want to know more about the STi's engine specifically, even more specifically what differences does it make between it and the EVO's more standard inline four, if it does make any differences throughout other parts under the hood.
Any links or just explanations are appreciated!
Thanks,
-TD

 

The pistons move horizontally, not vertically.
The engine is smaller height wise (as you would expect) thus it can be mounted lower in the engine bay.
Rather than having a single exhaust manifold, it has two.
It uses an upipe/downpipe setup rather than mounting the turbo directly to the manifold.
It has four camshafts, not two.
The intake manifold is on top of the engine rather than on the side.

 

Damn good motor too.

 

Ssshhhh...you'll get all the fanboys riled up.

 

Okay so mounting it lower means a huge change in center of gravity for the car, right?
and two exhaust manifolds seems like it would allow more horsepower to be generated. That's more information than I could find anywhere on google. lol.
Thanks!
-TD

 

Number of exhaust manifolds has nothing to do with power.

 

It wouldn't let exhaust flow more freely?

 

Not really.

 

oh. put that in your signiture then.
lol, I'm so newb at this. haha
-TD

 

Here is the intake and exhaust diagram for a Subie, but it gives a good idea of the overall engine layout.

There is a secondary market for using Subie engines in small DIY one-off aircraft and in one-off sports cars due to the very low profile.

 

^that's a pretty neat diagram, thanks.
and that's very interesting, too, that they're used for other purposes.
-TD

 

Apparently its the design of the OE manifolds that make it sound like the "typical" boxer motor. Reverberation that it causes makes that lumpy noise. There are some aftermarket manifolds that make the car sound like a typical 4cyl. Nice diagram btw.

 

What is well known is that the Evo 4G63 will easily surpass the Subie motor when it comes to mods. It can also hold more power as well as I have a few Subaru friends who've all blown their motors.. Pistons/cylinder walls crack.. especially Piston Number 1. After it's built, it's a much more stout motor. They are well known for their stout transmissions, however some complain about the short gear ratio on the older STI's.

The steering ratio is not as tight as ours.. If you drive one you'll instantly feel the difference when you turn the wheel.

 

The design is also naturally balanced, so balance shafts aren't necessary for smooth operation, which means less rotating weight.

 

Tis a nice design really, if only it was easier to work on.