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Old 08-31-2006, 08:11 AM   #1
nomorem3
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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...

Johnny

Last edited by nomorem3; 08-31-2006 at 08:22 AM.
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Old 08-31-2006, 12:26 PM   #2
Hyper
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oh..... you got it all wrong...... where do I start

1. V9 is NOT dual AVCS. The only dual avcs is the B4
2. V9 and V8 are almost identical. Same wiring harness, same 5 plug ECU...... difference is in intercooler and some other stuff. I believe internals are identical within versions (V9 RAC = V8 RAC, V9 = V8) but I am not 100% sure
3. easiest way is to keep DBW, if you use JDM ECU you have to rewire everything (PITA)
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Old 08-31-2006, 02:07 PM   #3
nomorem3
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I'm just going by what i've been told. That's why I started this thread, wanted to know the facts, appreciate your input.

I always thought that the new STI (06+) had an updated AVCS system, thought it controlled both cams. What is the difference between the V8 & V9 heads then? Re-educate me on the reason for the upper cased "I" in STI, as compared to the lower cased "i" in the 04-05 STi. I know it has something to do with the VVT, right? haha.

Just to make sure, to get the V9 STI heads to work correctly in my 4-plug DBW 05' USDM STi, do i modify the V9's 5-plug harness or my USDM STi's 4-plug harness for the Autronic SM4 EMS to work with the V9 heads/sensors etc.?

I gotta get goin to work...

Anyone mind helpin me out here? Basically I need to know what exactly I need to do to get the JDM V9 STI heads & Intake Manifold to work w/ my 05' USDM STi w/ Autronic SM4 EMS (keeping DBW of course). Since i'll be using a standalone, and not JDM ECU, wouldn't that also allow me to install the JDM V8 Spec-C heads w/ DBW instead of throttle-by-cable?

I can get a very good deal on the V8 Spec-C heads, so unless the V9's AVCS is different than what I already have, I guess i'll go the V8 route again.

Thanks for your help!!

Johnny
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Old 08-31-2006, 08:38 PM   #4
Hyper
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AFAIK only the B4 comes with dual avcs on both intake and exhaust
I have not seen V9 heads open, so I really couldn't tell you if they are any different from V8 - everyone has his own opinion on this, but I won't say anything untill I see it with my own eyes

DBW STI has AVCS too, so I am thinking you could keep your harness and wire the 8 wires to the V9/8 heads. Also keep in mind, to keep DBW (which seems to be the easiest way) you gotta keep your DBW intake manifold (unless you can convert V8/9 intake mani to DBW )

AVCS is same in all JDM STIs, it's just a system The difference lays in:
1. cams
-Spec C have MORE agressive cams, thus better to go V8 Spec C rather than usual V9 (V7 spec C = V8 cams, but we are not touching V7 here)
2. tuning
-Spec C's have more agressive AVCS mapping...you can program AVCS map...Autronic supports it right? I've never dealt with that brain

Hope I clarified it
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Old 09-03-2006, 03:58 AM   #5
nomorem3
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Yes sirree Autronic has intake & exhaust cam control (VVT/VANOS (BMW own4g3)/AVCS)...

So what does the capital "I" mean again in the new STI, as compared to the lower cased "i" in 04-05 STi's? I could have sworn that it had SOMETHING to do with the "new" AVCS.

If in fact the AVCS is the same in the V8 & V9 heads, for damn sure i'm going with the JDM V8 RA Spec-C heads, cause I'm only paying $1500 for em!!

Now onto the Intake Mani./TB subject...you don't think my DBW TB from my USDM 05' STi will bolt onto say a V8 "Long Runner/Non-TGV" Intake Manifold? they should be the same size & have same bolt pattern shouldn't they??

The harness can be modified, so that's not an issue.

So now i'm stuck, because I always thought that the new STI had a different AVCS system. Reason:

1) Read it online when it came out
2) Raced a stock 06' STI w/ 3 passengers, in my bolt-on (K&N SRI, Perrin FMIC, NGK Iridium 7's, UTEC, Walbro 255, Invidia Catless Bellmouth, & JIC 505S Full-Ti w/o Resonator) STi @ 22psi, with removed - trunk lining/spare/IC Spray Syst/Rear Seats & braces/Washer Reservoir, iON Perf. 2-pc rotors w/ Ti fasteners, & Zeal V6 coilovers. On a VIRTUAL freeway starting in 3rd gear to end of 5th. He stayed RIGHT next to me from 3rd to 4th, I started to pull before end of 4th, and had a major pull when i hit 5th. I'm guessing the power kicked it in @ higher speeds while his newer STI (AVCS? or something) had the advantage in the lower speed/trq dept.

I mean, I've beaten many SC Cobra's (from dig & freeway), my friends C5 Z06, friends modded WS6, brother's 400hp E46 M3, but the new STI was just surprisingly unexpectedly quick down low.

Could have been that he was in a lower gear before me, but I could have sworn we started at the exact same time, and for buddah's sake mine's a bit lighter!!
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Old 09-03-2006, 01:13 PM   #6
Hyper
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STI vs STi I thought you were joking, someone must have made that up

$1500 is an ok price for spec c heads imho, about average

intake manifold, I honestly can't help you here as this is something I've never looked into

wiring harness...... well, if you really want to run JDM ECU (then forget about passing inspection), you have to get the whole engine/dash harness V7+ or custom add and change wires, as the pinouts are absolutely different JDM vs USDM
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Old 01-23-2013, 11:24 PM   #7
D-Rodman
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Check out the ej207 info thread, you'll find some useful info that may help answer some of your questions.
Search, ej207 info

Last edited by D-Rodman; 01-24-2013 at 12:04 AM.
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Old 01-25-2013, 01:02 AM   #8
D-Rodman
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You are not running Jdm avcs with a Jdm or usdm ecu with an accessport. A Jdm v7, v8 is an easy swap into a 02-05 wrx using the corresponding jdm ecu and avcs wiring. A v9 with a v9 Jdm ecu is more complicated because the ecu is immobilized so you would also need the ignition and key from the donor vehicle. The only exception been a v9 spec c that are not immobilized. In any case you will be running open source engine management. You could run a v9 engine with a v8 fairly easily, some sensor adjustment are needed and tunning for whatever stuff you run like exhaust, etc. A v7 is also possible, same deal with sensor calibration in the ecu just like using a v8 ecu but the v8 and v9 engines come with twin scroll turbos while v7 come wit single scroll. All this info is available on the ej207 owners and ej207 info thread, search, read.
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Old 04-06-2013, 09:57 PM   #9
ssssly
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Don't know why people in the states like to argue this point.

Many v9 STIs have dual AVCS heads. Almost all the late productions before the GR change over. Have parted several of them. Most of the GDGs I have seen are dual AVCS. GDFs are all single AVCS. The confusion is stateside people like to use Vwhatever instead of the actual designation. GDA-G.

The cam profiles throughout the GD series also changes. GDA,B lower profile, C-F higher profile, D-F spec C/S series very high profile. The spec C cams run profiles normally in the range of aftermarket "stage 1" cams.
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