How to ID your EJ207
The easiest way, is to look for a white sticker, on the bottom of the left timing cover.
Then take the number there and compare it with the table that I posted the link to above, then find out what engine you have.
What if the sticker is missing, or you suspect it's faked ?
You have to think for a minute. If somebody is going to fake the sticker, what would be the purpose of doing that?
Financial, to charge more money, to make the engine more desirable.
So then, there could be suspicion that an engine is not really a Spec C.
But now we know what a spec C should really be...
A spec C is for most of the part an Sti engine with a few add-on parts. If the add-on parts are there, then it's a Spec C engine, it's as simple as that. There would not be any point in adding all the spec C parts to an Sti engine, in order to fake it.
In sum: If this is not a V7 spec C, then if it has the VF36, if the ECU checks out to be a Spec C code number, if the ROM checks out to be a Spec C ROM, if it has no cruise control, then it's a spec C..
It could be a Spec C with the oil radiator option or with the no A/C as well.
Manifold for oil above the filter, instead of cooler, for the oil radiator option..
If it's a V7 spec C, you would have to acquire the knowledge of reading the codes etched on the camshafts, then pull the valve covers and ID the camshafts.
Here I will ad camshaft info.
Below for now are some specs for v8+ cams
Here is information about the clearance to deck, the distance from the top of the piston at TDC and the gasket plane, as well as compressed gasket thickness:
For V7 RA clearance is -1.5 +/- 0.5mm
For V7 Spec C clearance is -1.5 +/- 0.15mm, headgasket crushed 0.7 +/-0.2mm
For V9 clearance is -1.5 +/- 0.15mm, headgasket crushed thickness is 0.7 +/- 0.2mm
For V10, clearance is -1.5 +0.15mm to -1.5 -0.30mm, headgasket crushed thickness is 0.7 +/- 0.2mm
If it's an S engine, it has been said that there are clear maks of it having been ballanced, visible by the flywheel. The ECU carries a special sticker with a serial number, maybe that can be traced to one of the numbers on the block.. Not to mention that if the VF42 is present, odds are good that it's genuine.
Some Spec C engines do not come with an A/C compressor. This was not an option package, it was a spec C model. For a while people believed that a Spec C did not have A/C and that a Spec C type RA did have it. This is not the case, both cars were called Spec C type Ra, or in Subaru designaton RASC.
The factory created a dedicated metal belt cover, that replaces the plastic belt cover, for this engine.
Here are some photos of these.
Typical tune up and replacement parts
I'm not going to go into what some people have substituted and the engine still ran. For that it's still best to ask on the EJ207 thread. This is a decision every person has to make, based on their budget and ideas.
There are a very large, majority number of parts that are the same between USDM and JDM.
There are a small number of parts that are speciffic to this engine.
Those can be bought through IAP or Japanparts.
Specified in the owner's manual are the NGK PFR7G with 0.7-0.8mm gap
There are some NGK that have a similar part number, but wrong gap. It has been said that attempting to re-gap these plugs results in having misfires.
The iridium equivalent of these plugs is available, it's the best choice. Get the BKR7EIX, or BKR7EIX-P, but not BKR7EIX-11.
I have seen specified for a V9 as racing use PFR8G, in the Sti catalog.
The V7 gets 11044AA482/483, the same as an '02 USDM WRX EJ205.
The V8-9 gets 110AA651, not the same with any USDM gasket.
The timing belt has a different part number than any belt sold in US. The replacement interval is at 62K miles. Coincidentally, the reinforced Sti timing belt sold here in US as the Sti pink belt, also has the replacement at 62K miles and the same part number for this belt is also specified for the EJ207.
I think that there is a mandated minimum timing belt replacement interval and that softer belts meet that, for USDM.
For higher rpm you need a more rigid belt, which in turn requires replacement more often.
So I reccomend the Sti pink belt, because by the time you buy the OEM belt from Japanparts, if you really shop the pink belt well, the prices will be similar. For probably $20 less, you can also get the reinforced belt from a different supplier: Gates, by example.
When you replace the belt, replace also the silver sticker on the right top side of the timing cover. That keeps track of belt replacements.
If you have the oil radiator option on a Spec C engine, you need to use a 2008+ WRX (non-sti) water pump, it's the proper part number.
For the regular setup, a 2005 USDM water pump is good for V8 and 9.
V7 has a part number not found in US. Check the thread for substitutions.
I just took of mine, walked to the parts counter at the dealer and bought identical replacements. If you have the no A/C Spec C engine, this may be a bit different.
It's the same part number as for the USDM GDB WRX & STI
V7 get the USDM WRX 2.0 coil packs for '02, the rest get the '05 WRX ones.
Twinscroll wastegate actuator
The stock actuator is rated at 12.3 PSI.
I will expand this later
If you finished the swap, turn the key and before trying to start, the check engine light does not come up, the fuel pump does not prime, you may have an immobilized ECU
Once the swap is in, get yourself familiar with logging and start checking the parameters of your engine BEFORE you start driving around.
Odds are, you will need a tune to get your engine within safety, to protect your investment.
As far as the fueling, Subaru decided to settle the urban legend of the "JDM Super-fuel", by printing in the 2015 BRZ Owner's manual that the JDM Octane rating of 98 RON is one and the same with the USDM octane rating of 93 AKI.
This has been a looong-running urban legend and it took a lot of time posting, researching, to bring this to light.
It is important to note that tuning wise, that which applies to the EJ257, timing-wise, is not one and the same with an EJ207.
This can be easily seen, by comparing the timing tables of a JDM EJ257 (as seen in the Sti A-line), with the JDM EJ207 timing table.
The 207 needs its timing, to shine.
Adjustments need to be done based on your mods and surely if you can't fuel 93 AKI.
If you don't know much about tuning and wish to understand what your tuner did to the timing of your EJ207, look at the torque curve, on the dyno.
Take a 2004 V8 Spec C engine:
From the factory it's rated at 304 ftlb. Now, we know that the torque rating is not crank/wheels, but only one value, corrected to the engine.
Say that your dyno results are 320WHP but 280 Ftlb.
This means that your tuner gave you less torque than the factory, they tuned your engine down. If the fuel quality is the problem (you can't fuel 93 AKI), then this is the explanation.
A timing-rich tune often yields dyno results where the torque number is higher than the WHP number. This is how you ID your tune.
Some tuners will give JDM fuel rating as a reason for removing the timing from your engine, then will bring up reliability concerns.
The overwhelming tuning method is the boost based tuning.
The factory did a timing based tuning and many tuners remove this.
Building on top of the factory tuning is also an idea, something I always had an interest in and worked on.
Here is a link to the 207 owners thread.
Here is a link to the twinscroll stock location upgrade thread.
Newer Twinscroll turbos from GRB body '08+: VF49, 53, 56 are backwards compatible with V8, 9 engines