vortec 4200 - >> vvt setup - questions >> GM 7X

[ca434sbc4]

Attached is a msq using the settings I got from JAM.


Since the engine only has VVT on the exhaust cam and the cam default position is full advance - it can only retard (normally 50* crank degrees) - on my setup I have physically limited the retard to 32* crank. The EDIT camshaft sensor is on the exhaust cam.
The limiting is to prevent a piston to valve interference as the installed exhaust cam has ~ *70 more duration than the factory cam.

Observation in the manual - it state that VVT only works with toothed wheel.. I imagine that since we are working custom tooth wheel decoder - VVT is actually enabled...

A few questions:

1) can we select # of cams as "1" under cam setting, (exhaust cam) it is using the main cam input? If not why not? Not sure why JAM has 2 cam selected.

2) in the cam setting parameters - what is the method to determine the min and max absolute deg settings? ( the cams are chain driven and not accessible during operation). I understand using test mode to move the cam based on %DC - where do we get the resultant deg offset readings?

Thanks

[jsmcortina]

Initial VVT setup is described in the Megasquurt-3 Setting Up manual.

James

[ca434sbc4]

thanks - I went looking for it before posting and as usual didn't look in the right spot.

[ca434sbc4]

VVT setup - I'm getting some odd 0 and 100% vvt angles. >>> GM7X

1) I found and read the VVT setup page.

2) with variable VVT , 1 cam (exhaust), main cam sensor enabled, min & max angle fields == 0.

3) set test mode 0% I read ~6.3*. with 100% set I read ~ 97*

Only problem is the VVT actuator has a max range of 50* crank ( and actually this one has 32* MAX since this VVT is mechanically modified to limit the range).

So I don't understand why the extraordinarily high upper cam angle is occurring.

The other item - which is probably mechanical is it takes ~70% PMW before the cam moves and then swings to the max limit. I'll test the solenoid this week.