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Old 08-31-2006, 08:11 AM   #1
Scooby Newbie
Member#: 73469
Join Date: Oct 2004
Location: Cali
2005 STi - Black
2002 540i - Black

Your NASIOC Administrator Differences between JDM V9 STI, JDM V9 Spec-A/B/C, & JDM V8 Spec-C (Heads)???

Title says it, other than the V9 having "Dual-AVCS," V8 using Thorttle-By-Cable & 5-plug Harness, and the ECU differences, were there any changes in head design from V8's to V9's?

I ask because I was planning on running the V8 STi Spec-C Heads/Intake Mani/ECU on my sleeved/built 2.5L block, until it was brought to my attention that the JDM V8 Spec-C uses a 5-plug harness and Throttle-By-Cable.

But I was told that the JDM V9 STI has a 4-plug Chassis Harness connection that is compatible w/ my USDM V8 STi. Of course the DBW is also a plus, one that also allows me to easily reverse my intake manifold.

I was also told that the V9 STI & V9 STI Spec-A/B/C all use the same head, but differ solely due to the differences in their ECU's. Also was told that that head is the same as the JDM V8 STi Spec-C (Except of course the V9 having AVCS on both cams & V8 on only intake) , as far as the "Large Port" heads w/ additional hand porting of intake ports, aggressive cam profile, stiffer sodium filled valves, and beefed up valvetrain.

Also, if anyone knows more detailed specs of the cams in these heads, I'd really like to especially know the cam duration of the V8 & V9 heads. Just to confirm, the JDM V9 has "Dual-AVCS" correct? That's valve timing control (retard & advance) on BOTH the intake & exhaust cams??

EDIT: Post-Brain Fart - Is there a difference between the V8 "1-pc/Long Runner/Non-TGV" Intake Manifold & V9 one?

Mind just went blank *brain fart*

Guess I'll just address my other interests later on...

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Last edited by nomorem3; 08-31-2006 at 08:22 AM.
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