Engine Progress
The car has been on hold for a little while since the engine and heads were at the machine shop. The block was being bored from 2 liters to 2.2, and matched to the Tomei strocker kit pistons.
The heads were purchased off a JDM Spec-c engine from a guy on NASIOC. The engine was involved in a fire, so the heads needed a lot of cleanup work, and some machining to match the new block bore size. Once back from the machine shop, the difference was night-and-day. They look like brand-new heads.
Once these were back, I took time to create some comparison diagrams illustrating the differences between the USDM STI (EJ257)block versus the JDM STI (EJ207) block.
Block comparison: USDM STI EJ257 vs JDM STI EJ207
I was checking out my block compared to a USDM STI block, and noticed many differences with respect to cylinder wall thickness, and coolant chamber capacity.
It seems the EJ257 will be better application for street cars, and drag racing where heating isn’t as big a problem compared to road racing. This was also the conclusion Subaru came to in their white papers.
The EJ207 has continued to be used in Japan and Europe in road-racing applications due to its cylinder wall thickness and enhanced cooling capacity.
Head comparison: USDM STI vs JDM STI Spec-c
Right off the bat, the Spec-C heads have significantly larger intake ports, The intake splitter is also much more recessed into the head. The porting is much finer, and most of the casting burrs have been removed.
More images are in the Gallery - Car Build: 2008.02.23. Check em out.
March 5th, 2008 at 8:01 pm
Cool stuff!
One thing though, I always thought the term USDM cannot apply to a car that’s not made in the US. Subaru only has one domestic market: Japan.
March 6th, 2008 at 6:56 am
Good call, so is there a term for a Japanese company making products aimed at international markets?
March 11th, 2008 at 2:50 pm
I’d just call your car “US” or “US spec”