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Old 01-11-2009, 12:39 AM   #1
watchunglava
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Default I-avls

http://www.drive.subaru.com/spring07_whatmakes.htm



"The ecm automatically selects the different cam lift profile settings based on engine load requirements, and atmospheric conditions"



Does anyone know what these parameters are? Sounds to me like the cl/op transition.
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Old 01-11-2009, 12:44 AM   #2
sniper1rfa
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My guess is that it uses RPM and some sort of expected load to determine which profile is optimal. Probably determined via empiric testing (dyno tuning).

On a dyno, you would see that the point at which it switches is where the two torque curves (one for either profile) cross under a given set of conditions.

Probably williaty can chime in on exactly what inputs it uses.
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Old 01-11-2009, 01:45 AM   #3
RaceFaceXC
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"The ecm automatically selects the different cam lift profile settings based on engine load requirements, and atmospheric conditions", so the parameters are Engine load and atmospheric conditions (temp, baro., etc) Also, if you look at the paragraph before the quoted text, you will see that oil pressure is the mechanism for engaging and disengaging the high lift lobe from the 2nd intake valve. So engine speed should also have some bearing on when it is active.

The RR forums have a little bit about this, but most discussion is about tuning the valve control of the turbo engines. I dont think there are any benefits from adjusting the parameters on the n/a i-avls. They are optimised for all scenarios, is what i took from it.
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Old 01-11-2009, 10:46 AM   #4
sniper1rfa
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they use oil pressure only as the working fluid, probably so they don't have to route any lines through the heads (they can just use the ambient pressure in the head). I'd imagine the optimum switch point is never low enough that oil pressure is a concern.

Also, keep in mind the quoted text was written by the advertising department, and should be taken with a HUGE handful of salt.
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Old 01-11-2009, 12:16 PM   #5
watchunglava
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yea merch god over at rom raider says its pretty much b.s. and that the i-avls map uses different parameters than they say.



has anyone taken apart an i-avls head??? is there a sensor on the rocker arm or something?? how does the ecu control it mechanically?
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Old 01-11-2009, 02:59 PM   #6
Eyedoc Orlando
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There is a sound change around 3300-3500rpm, so I suspect that's where the AVLS tends to kick in. It probably has a minimum RPM and minimum load requirement.
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