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?