VCT Question

[702GT]

When the phasers are relaxed and uninstalled, what position do they naturally sit in? Full advance or 0 degrees? Did a set of phaser lockouts from BBR in my buddies 2v-3v swap, he asked and I honestly didn't know. I never really thought about it, lol.

Also curious, if the VCT solenoids are installed but not connected to a harness, are they fully shut like a nitrous solenoid?

 

[Alfiedagr8]

The phaser are in the full advance position. And the sol when energized allow oil flow to the Phasers. So you can leave them unplugged.


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[BruceH]

When the phasers are relaxed and uninstalled, what position do they naturally sit in? Full advance or 0 degrees? Did a set of phaser lockouts from BBR in my buddies 2v-3v swap, he asked and I honestly didn't know. I never really thought about it, lol.

Also curious, if the VCT solenoids are installed but not connected to a harness, are they fully shut like a nitrous solenoid?

Full advance is 0 degrees. They can only be retarded with vct.

 

[702GT]

Interesting, so VCT plays between 0 degrees and 30 degrees of retard? What's the whole 60 degrees business? Is that including both cams? I always thought if its 60 degrees of VCT, it would be 30 degrees in both advance and retard FROM 0 degrees?

 

[JeremyH]

60 crank degrees. Only retards, like mentioned zero for the cam is at full advance.

 

[702GT]

Now you're fuckin with me. Dont bring crank phasers into this, I'm learnin cam and phaser degrees today damnit!

 

[JeremyH]

Now you're fuckin with me. Dont bring crank phasers into this, I'm learnin cam and phaser degrees today damnit!

LOL, no crank phasers here, the 60 degrees is the cam measured in relation to the crank.

 

[JeremyH]

LOL, no crank phasers here, the 60 degrees is the cam measured in relation to the crank.

 

[702GT]

GTFO!

So if you command say 10 in the tune, is that 10 degrees each cam for a total of 20 or 5 degrees each cam for a total of 10 degrees retard?

 

[BruceH]

GTFO!

So if you command say 10 in the tune, is that 10 degrees each cam for a total of 20 or 5 degrees each cam for a total of 10 degrees retard?

Not sure if you are serious or not. If so then you are overthinking it. 10 degrees commanded is 10 degrees of retard for each cam, they don't add.

 

[702GT]

I think I'm over thinking it because I thought it was implied that it's relevant to crank degrees. Each cam being 10 degrees retard is a total of 20 cam degrees retard to the crank? As the FAQ states the VCT runs 20-40 degrees if retard at light loads, in order to state you have 20-40 degrees retard in cam angle from cams that each have a max of 30 degrees, you're adding them together. No? I'm just asking if tune value is per cam or combined cam timing when a value is set?

 

[BruceH]

I think I'm over thinking it because I thought it was implied that it's relevant to crank degrees. Each cam being 10 degrees retard is a total of 20 cam degrees retard to the crank? As the FAQ states the VCT runs 20-40 degrees if retard at light loads, in order to state you have 20-40 degrees retard in cam angle from cams that each have a max of 30 degrees, you're adding them together. No? I'm just asking if tune value is per cam or combined cam timing when a value is set?

Nope, they each have their own chain to the crank sprocket. Crank degrees are the reference for things like fuel injector timing, tdc, bdc, and how the valves open and close in relation to where the rotating assembly is.

If you really want to overthink it look up the specs for whatever cam you plan to use and start plotting when the valves will open and close and how long they will stay open or closed. Then try to figure out how that compares with stock and take a stab in the dark about where and how much to retard the cams. Then try to guess some more by datalogging airflow with different vct patterns. Finally take it to the dyno and start the real testing.

My life would be alot simpler without this car.

 

[702GT]

You go straight to hell with all that jazz! I pay my tuner to do the thinking LOL.