Engine Basics - Please help a dunce out! :)
 

With all sorts of engine variants out there, can those in the know help out?

Blocks:

EJ20 - 2 litre - EUR and JPN models only, Open or Closed deck. (This refers to the cooling channels in the block, where closed deck is more robust?).

EJ25 - 2.5 lite - US (and now EUR 2006). Open deck only.(??)

My MY01WRX can only push out 300-350 bhps due to the open deck and WRX heads. So, to put out more power/boost (gearbox aside), I can use the existing block, but need Sti heads, new cams, pistons, cranks, rods etc. Is this correct? Closed deck block would mean a more robust engine, depending on desired power?

I'm trying to weigh up whether to carry on modd'ing or get a different car! Guess it all depends on cost.

2 litre closed deck blocks only came on the early WRX and Legacys untill about '94
AFAIK all STI 1 and 2's had Closed decks. STI 3's are questionable!!

All the rest of the 2 litres have open decks.

The US 2.5 NA engine (EJ25) is open deck and was also used in the Legacy.
The US STI 2.5 from anbout '03 on ([b[EJ257[/b]) is a Semi-closed deck.

With the right turbo and supporting mods you might see 400bhp but it could be expencive. Changining rods and pistons will help the reliability at higher boost levels :)

It depends what you goal is and where you want to stop ;)

When to stop is always a problem!! :)

I guess this is why most people go for US 2.5's compared to rebuilt 2.0's...

Still wonder why Jpn continue to use 2.0's compered to 2.5's... i guess its for emissions?

so is the closed deck block better then for higher power outputs? (with better internals)
I have an ej20 on a my93, is then any way of checking without stripping the engine, if it is closed deck block or open?