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Old 01-01-2007, 09:04 PM   #1
dexterous
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Default Will JDM STI AVCS cams in USDM STI AVCS heads?

I have been searching for a good while now and I have found lots of info about using AVCS JDM cams in non-AVCS USDM 02-05 WRX heads but nothing about using JDM AVCS cams in the USDM STI AVCS heads.

Will JDM AVCS cams fit in the USDM STI AVCS heads and work correctly assuming proper tuning and supporting mods? To me, supporting mods to the heads would include valvetrain modifications to support 8K RPMs and porting.

I don't have huge power goals or anything. I would be very very happy with a well running motor making 375-400whp and the ability to crank to eight grand without the power dropping like a rock form the early sixes.
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Old 01-02-2007, 03:13 AM   #2
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Yes, they fit. But JDM STI cams have less lift and more duration compared to USDM STI cams.
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Old 01-02-2007, 09:38 AM   #3
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less lift?
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Old 01-02-2007, 11:48 AM   #4
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The cam sensor pick ups are completely diffrent, I'm not sure if you can make the avcs work
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Old 01-03-2007, 10:43 AM   #5
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Interesting. So does anybody have any recommendations for CAM options? Am I correct in thinking that I would need cams to have a well rounded motor spinning to 8K?
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Old 01-03-2007, 09:45 PM   #6
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The pick ups are completely different. Why not purchase a set of aftermarket avcs cams?
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Old 01-03-2007, 11:12 PM   #7
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Quote:
Originally Posted by dexterous View Post
Interesting. So does anybody have any recommendations for CAM options? Am I correct in thinking that I would need cams to have a well rounded motor spinning to 8K?
If you are spinning to 8k I'd get bigger cams than stock, I don't care what stock motor they were in.
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Old 01-04-2007, 08:11 PM   #8
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Quote:
Originally Posted by zanderspeed View Post
The pick ups are completely different. Why not purchase a set of aftermarket avcs cams?
Sure, recommend something and I will look into it.
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Old 01-04-2007, 09:33 PM   #9
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Old 01-05-2007, 01:52 AM   #10
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Quote:
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less lift?
That's how high the the valves open and the duration is how long they stay open.

Ron
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Old 01-05-2007, 02:43 AM   #11
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yeah i thought they had more lift and more duration... but maybe i'm just ASSuming. i know they are more aggressive than usdm, but maybe that can be achieved still with less lift but more duration? i'm a cam noob.
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Old 01-05-2007, 07:31 AM   #12
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yes they will fit, the only thing youl not have is the mid rang power that the AVCS will normally supply you with.

with AVCS the timing will be different between RPMs.
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Old 01-07-2007, 05:45 AM   #13
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It seems there are two types of pick-up for the AVCS sensor on the rear end of the cams. The JDM cams have 4 positive signal pick-up points on the cam, whereas the USDM cams seem to have negative pick-up points (slots). Can anyone comfirm this?

I'm running JDM Legacy EJ20X/Y heads/cams on a USDM Legacy EJ255 ECU and loom, with AVCS working, meaning the USDM cams must have the same slots as the JDM Legacy EJ20X/Y have (so the JDM Legacy EJ20X/Y cams differ from for instance JDM STI cams regarding AVCS pick-up).
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Old 01-07-2007, 01:45 PM   #14
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The USDM STi AVCS cams do indeed have slots at the rear. I forget how many though...

-D
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Old 01-07-2007, 09:50 PM   #15
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Quote:
Originally Posted by Marnix View Post
It seems there are two types of pick-up for the AVCS sensor on the rear end of the cams. The JDM cams have 4 positive signal pick-up points on the cam, whereas the USDM cams seem to have negative pick-up points (slots). Can anyone comfirm this?

I'm running JDM Legacy EJ20X/Y heads/cams on a USDM Legacy EJ255 ECU and loom, with AVCS working, meaning the USDM cams must have the same slots as the JDM Legacy EJ20X/Y have (so the JDM Legacy EJ20X/Y cams differ from for instance JDM STI cams regarding AVCS pick-up).
That would have been great to know when MZM was working on my WRX with EJ20X swap that that couldn't get to run correctly without the proper ECU.
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Old 01-08-2007, 06:33 AM   #16
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I almost ordered JUN AVCS intake cams for a customer's engine which runs EJ20X/Y cams on a USDM MY05 Legacy GT ECU.

I'm now discussing with JUN if they can supply the cams with the other AVCS pick-up pattern. If they can't, I will use standard Subaru intake cams off a MY07 Legacy 2.0R. Those are atmo cams with AVCS, 248 degree (standard turbo AVCS cam is around 240) and 9.8 mm lift. The atmo engine makes 168 ps @ 6800 rpm.

I think the difference (slots or ribs) has to do with solid cams (cast ribs) or the latest hollow cams (slots machined into them).

Last edited by Marnix; 01-08-2007 at 06:42 AM.
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Old 01-08-2007, 11:33 AM   #17
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The pickup points and sensors are completely different. The JDM are two-wire magentic sensors. The USDM STI sensors are 3-wire hall-effect sensors.
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Old 07-31-2008, 08:36 AM   #18
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EJ25 heads + cossy euro/japan spec cams + euro spec ecu + euro AVCS sensors

Would these combo work?

AVCS solenoid bracket needs a little work but i think it is ok.

Any ideas?

Thanks
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Old 04-26-2011, 11:50 PM   #19
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white knight, did you ever figure out if the combo worked? I'm about to buy a 207 just to measure things up and see if the JDM ecu, cams, sensor and solenoids can be used...basically all the parts that are easy to buy. Heads are hard to come buy and guys seem to think they are gold or give ZJs.
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Old 04-27-2011, 08:51 AM   #20
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Im curious as well for the same reasons.

Last edited by biodude; 04-27-2011 at 09:00 AM.
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Old 04-27-2011, 10:16 AM   #21
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I have a ver8 jdm engine, the cams profiles for the pickups are positive, not negative like the usdm, I don't see why you couldn't use jdm cams in 2.5 heads as long as you used the ecu that was needed as well the holes should be the same where the cams bolt up, so for building an engine it would be ok, or for doing a hybrid, just remember you need everything including the jdm engine harness., also they have more duration and less lift which aids in higher rpms
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Old 04-27-2011, 10:29 AM   #22
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I know the difference in sensor type and cam trigger but I'm wondering as to placement in degrees relative to crank the difference is in trigger times and sensor placement...also no one has been able to clarify (including Dave @ RalliSpec, Steve at IA performance) if the sensors can fit. Though Dave was saying that he doesn't think JDM sensors will physically fit without some machine work.

I've also brought this thread back from the dead. I hope Waxed can be more specific on sensor alignment.

http://forums.nasioc.com/forums/showthread.php?t=992216
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Old 04-29-2011, 08:09 PM   #23
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Quote:
Originally Posted by Marnix View Post
I almost ordered JUN AVCS intake cams for a customer's engine which runs EJ20X/Y cams on a USDM MY05 Legacy GT ECU.

I'm now discussing with JUN if they can supply the cams with the other AVCS pick-up pattern. If they can't, I will use standard Subaru intake cams off a MY07 Legacy 2.0R. Those are atmo cams with AVCS, 248 degree (standard turbo AVCS cam is around 240) and 9.8 mm lift. The atmo engine makes 168 ps @ 6800 rpm.

I think the difference (slots or ribs) has to do with solid cams (cast ribs) or the latest hollow cams (slots machined into them).
please any info about the EJ20X
are they like the EJ205 or EJ207 ?
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Old 04-29-2011, 09:39 PM   #24
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I have the jdm Cam sensors, let me see if I can either find usdm sti Cam sensors or if I can find a 2.5 to try them out, they look the same, I can snap a pic tonight
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Old 04-30-2011, 02:11 PM   #25
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if you can get a side by side and actual dimensions (tip length from shoulder, offset from center of bolt hold to center of pick up, and tip diameter).

I think the big issue is going to come with alignment of heads and cams triggers.
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