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Old 11-15-2011, 10:22 PM   #1
Scooby Specialist
Member#: 96919
Join Date: Sep 2005
Chapter/Region: MAIC
Location: chesapeake va
2004 sti

Default Buying a Ver9 motor for my usdm STI... need help!

hello, ive been in the usdm community forever and know nothing about the 2.0 version 9 motor.

I know its twin scroll, apparently forged internals, basically I can get a V9 longblock/turbo setup/intercooler ect.... for $3800 bucks. that is wayyyy cheaper then putting a new usdm 2.5 back in it and im looking for high reving, quick spooling.. which the 2.5 isnt good for. (on a budget anyway).

So, before I go pick up my "low mileage" ver9 setup, what should i look for to ensure that its a ver 9 motor.. and should i look for anything specific... like a specific VIN?

Whats "forged" about it?

I found some stock location turbos, 18, 20, and 60-1 on ebay that are pretty fairly priced and i might end up sticking one on it.

i have some Kelford 272's that were on the 04 motor..... would it be worth it to install them on the Ver9 motor? will I have clearance issues?

the ecu will be tuned with AEM.. so no AVCS, correct? its that gonna be a big deal, honestly? all our AEM 2.5's make great power without avcs.

any input at all is welcome.

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Old 11-16-2011, 08:22 AM   #2
Scooby Specialist
Member#: 96919
Join Date: Sep 2005
Chapter/Region: MAIC
Location: chesapeake va
2004 sti


Observations about different model changes:



The first model year of the new age style (bug eye) had two parts. The A.1 model section appears to use some parts that carried over from the Version 6 cars, while the A.2 included more new parts.

Blocks (Crankcase only in the JDM case)
The block numbers (not short block, just crank case) has stayed the same for all MY WRXs from MY01 to 05. The STI blocks changed in the MY03, so version 7 crankcases appear to be different from the

Version 8 and Version 9. Also note that Spec C crankcases are the same as the regular STI crankcases.

11008AA690: MY01,02,03,04,05 WRX
11008AA720: MY01,02 STI
11008AA980: MY03,04,05 STI


The WRX pistons were unique for MY01, and changed for MY03. These changed pistons in MY03(version were carried all the way forward to MY05. The STI pistons changes at the MY03 (version , and it is said that these new pistons were Hypereutetic instead of forged. Again note that the Spec C has the same pistons as the regular STI in each model year.

12006AB190: MY01 WRX
12006AC150: MY02,03,04,05 WRX
12006AB430: MY01,02 STI
12006AC430: MY03,04,05 STI


All MY01s and 02 use the same crank shaft PN, including the STI and Spec C. Note that the crank was updated however (from 210 to 240), and all replacement cranks in all WRXs are spec'd to use this new part. All WRXs from MY01 to MY05 use this same crankshaft. In MY03 (version the STI and Spec C received a new crank. This new crank was carried forward for all STIs in MY04 and MY05.

12200AA210: MY01,02,03 WRX MY01,02 STI
12200AA240: MY01,02,03 WRX MY01,02 STI [UPDATED]
12200AA270: MY03,04,05 STI


WRX rods received an update across all of the models sometime on 03. MY01 and MY02 STIs used the same rods. MY03 STIs received a new rod. All STI model years were updated to a newer rod (x180), which is the same rod used in the US STI.

12100AA081: MY01,02,03,04 WRX
12100AA190: MY01,02,03,04,05 WRX [UPDATED]
12100AA161: MY01,02 STI
12100AA170: MY03 STI
12100AA180: MY01,02,03,04,05 STI [UPDATED]


The MY01 and MY02 WRX used the same cam. Al MY01 STIs used the same cam. In MY02 the Spec C was given a special cam, and that special cam was used in ALL STIs in MY03. In MY03 all WRXs got a new cam, and again a new cam in 04/05. All STIs also got a new cam in 04/05. Note that all Spec Cs after MY02 use the same cam as the regular STI.

13037AA200: MY01,02 WRX
13037AA220: MY01 ALL STIs, MY02 STI
13037AA340; MY02 STI RA Spec C, MY03 ALL STIs
13037AA401: MY03 WRX
13037AA470: MY04,05 WRX
13037AA480: MY04,05 ALL STIs


This is interesting note. All the WRXs and STIs in MY01 and 02 are the same. In looking at these motors, the Spec C in MY02 appears to have a more ported inlet, even though it is the same casting. I suspect that the 'porting' is part of the engine build process, but when you buy a replacement head, this porting is not done. From what others have told me, this is the same with the Acura Integra Type R (When you buy a replacement factory head, it is not ported like the production car ones are).

Also note that in 03, all WRXs and STIs got a new head, carried to 04 and 05. For this reason, I'm assuming that the 04 and 05 WRXs and STIs use the WRX/JDM style cam sensors (3 sensors), not the new 2 sensor system used on the fly-by-wire US STI. (Actually I checked, and the cam sensors on all of the JDM cars has remained the same, so yes, the JDM WRX and STIs still use the older style. I suspect this will change in 06 with the JDM switch to drive-by-wire.

11039AB370: MY01,02 All WRXs and STIs
11039AB660: MY03,04,05 All WRXs and STIs


Notice WRX valvesprings are the same as the USDM ones. MY02 STI Spec Cs had a unique sping, which was not used again. When subaru went to the larger Spec C cams in 02, they must have tried a new spring. In MY03, when all STIs got the same Spec C cam, they decided to go back to the regular STI
spring. Perhaps the MY02 Spec C spring was too strong. Also the MY03 and up WRX got a new spring.

13217AA193: MY01,02 WRX
13217AA202: MY01 All STIs MY02 STIs (not Spec C), MY03,04,05 All STIs,
13217AA251: MY03,04,05 WRX
13217AA280: MY02 STI Spec C

US Market Cars:

Blocks (Complete Shortblocks)

10103AB330: MY02,03,04,05 WRX
10100AB440: MY04,05 STI

12006AC350: MY02,03,04,05 WRX
12006AC390: MY04,05 STI


As with the JDM market, the 02 WRX crankshaft was updated, and all MY03 and greater WRXs use this new crankshaft. I personally observed that my 02 Spec C crank was double drilled, while my stock WRX crankshaft was single drilled. I suspect the double drilling may have been the change from (0x210) to (0x240). Anyone with an 04 or 05 WRX crank could confirm this.

12200AA210: MY02 WRX
12200AA240: MY02,03,04,05 WRX [UPDATED]
12200AA260: MY04,05 STI

JDM Overlap:
WRX Crankshaft is same as JDM MY01-05 WRX crankshaft, as well as the JDM MY01,02 STI crankshaft.


WRX rods when thu several iterations, starting in the MY03 and again in MY04. MY05 received yet another rod update. All replacement rods for all series use this rod (0x240).

The STI rod is the same as the JDM STI rods. (However note that not all older JDM STI blocks uses this revision).

12100AA080 MY02 WRX
12100AA081 MY02,03,04 WRX [UPDATED]
12100AA190 MY03,04 WRX [UPDATED]
12100AA180 MY04,05 STI
12100AA240 MY05 WRX [UPDATED]

JDM Overlap:
x081 WRX rods are same as JDM WRX rods.
x190 WRX rods are same as JDM WRX rods.
x180 STI rods are same as JDM STI rods (all versions)


WRX Cams changed in 03,04, and 05. The 03 change was likly small, as they are backwards compatible to 02. The 04 change may be related to the change in MY03 to shimless buckets. All STIs use the same cam.

13037AA101 MY02 WRX
13037AA390 MY03 WRX
13037AA391 MY03,04 WRX [UPDATED]
13037AA490 MY04,05 WRX [UPDATED]
13037AA350 MY04,05 STI


All WRX heads have remained unchanged. The STI heads received an update in April 05 (Per Hotrods post below)

11039AB361 MY02,03,04,05 WRX
11039AB650 MY04,05 STI
11039AB910 MY05 STI [updated]


As with the heads, all valvesprings remained the same.

13217AA193 MY02,03,04,05 WRX
13217AA251 MY04,05 STI

JDM Overlap:
x193 valvesprings are the same as in MY01 and 02 JDM WRX.
x251 valvesprings are the same as in MY03,04,05 JDM WRX.
NOTE: No US cars use the JDM STI valvesprings.
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