I'm trying to figure out the diffrences between these two engines. I have a UK Ver. 7, possibly 8 engine going into my car and I know it is rated as having less power than its JDM counterpart. What is it exactly that accounts for the difference? I believe the UK motor has about 261hp. Is it basically just the difference in gas between the two countries? Is it also that the ECU is differently programmed? I think the UK also gets an extra cat as well.
But, the most important thing is are there any differences between the engine internals of the two, AVCS, etc. Any actual differences in just the engine itself?
Also, would plugging a UK engine into a JDM ECU basically make it a JDM setup, and would that even be worth it? Thank you for any help, I've been trying to figure this out for a while now.

 

garface,

I think the main difference is the exhaust on the UK being more restrictive.

Having looked it up I do know that 5th and 6th gear on a JDM are shorter than the UK.

Also, if the STi8 is anything to go by the JDM STi7 will have both manual and automatic intercooler waterspray buttons. There is another thread going on at the moment as to whether the UK is automatic or not.