JDM blobeye engine spec?
 

Hi guys - can anyone help with clarifying the engine internals on a JDM 2003 (blobeye) Impreza? Is the engine forged? Does it have uprated components compared to a UK spec blobeye?? Presuming the engine is healthy, what kind of power can it be taken up to safely? Many thanks in anticipation :)

Sorry to jump on but also might be worth asking are the Newage JDM Engines the same right through from 2002-2007?

The engine on a JDM Blobeye is not forged from the factory, they still use cast (hypereutectic to be precise) pistons. It's a common misconception that is about but it's just plain wrong, the JDM engine is considered stronger than the EU/UK equivalent but it can still suffer from major failure as has happened to the engine in my Spec C.

The engines in the JDM Bugeye STi did use forged pistons and connecting rods in answer to the second post, but from the Blobeye on they use cast pistons. :)

Post 2002 the pistons were not forged but hypereutectic cast alloy. The reason for this is A, cost; forged pistons are much more costly to produce and B; due to emission controls. Forged pistons when cold are a slightly 'loose' fit in the cylinder, allowing small amounts of fuel to become trapped in the gap. When the piston expands this is pushed out adding to the pollutants expelled. By adding silicon (this acts as an insulator) to the aluminium pistons (hypereutectic) this expansion is greatly controlled allowing much tighter cold tolerances.
Downsides are the pistons are more brittle due to the silicon content and the unabsorbed heat increases in cylinder temperatures, encouraging detonation. In terms of power handling, quite a few on here have run these engines up to and above 500bhp although I would say 450bhp is a safe limit IMHO. That is if the engine is in good health.

Many thanks Cannon and Einstein - much appreciated :)

Here's something I found on another forum some time ago and saved to my computer.

JDM V8 SUBARU IMPREZA WRX EJ20 ENGINE

THE JDM V8 Subaru Impreza WRX EJ20 Turbo Engine (AVCS) is superior to its USDM cousin in several aspects. As usual, the USDM WRX receives an inferior engine based on the older V6 GC8 motor.

The JDM WRX EJ20 on the other hand received an engine with all the bells and whistles that one would expect of a high performance engine. While the 2.0 displacement remains the same, the JDM WRX features a bump in compression (8.0 -> 9.0), better pistons developed using new hyper-cast technology (such as in the USDM STI), more aggressive cam profiles, better head casting, and of course the all mighty AVCS.

For those who are not familiar with AVCS, AVCS is a control device on the intake cams of the engine. Using an oil based pressure system, the cam timing is either retarded or advanced to increase or decrease overlap. This type of overlap essentially helps to create a “perfect” camshaft, allowing maximum power output throughout the power band while also assisting in emissions cleanliness.

The bottom line is the JDM WRX engine (rated at 246HP compared to 227HP) is far superior to the USDM WRX engine, and is what the USDM engine should have been. The improvements significantly reduce the notorious turbo-lag associated with the USDM WRX, allow the JDM engine to respond better to aftermarket modification, and produce a higher power output.

where did you rip that from?

I don't remember to be honest, was just doing a bit of research when I bought my jdm to see what the differences where. I remember it was a really old post by a firm called gruppe-s who were selling the engines new.

Here ya go found it http://www.clubwrx.net/forums/vendor...mediately.html

The STI engines have a few differences between the 2ltr units, the MY03/04 Spec C is more agressive than the standard STI but from the MY05 cars they are the same.
Some inifo on litchfields site :)

Tony:)

Do you Know if the uk bugeye sti uses forged pistons as well ?


Andy

Uk Bug STI has forged pistons and will take 450bhp.:)

those bugeyes were tough as hell!