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Drexal

VQ37 VVEL Control

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Hi All,

I'm wanting to run the Nissan VQ37VHR on my Link G4+ Thunder and was seeing if anyone out there has had any luck with this? In particular control over the VVEL. I've been debating a couple of ways to control this but some ideas would be much appreciated. I'm sure there are people out there who have control over it but I haven't found much information yet. 

So far I have spoken to @Adamw and he recommended using some sort of external speed controller - Example - https://www.vexrobotics.com/217-8080.html 

Another idea was manual control. Setting the VVEL at a certain level and locking it. Taking in account valve to piston clearance. 

 

Thanks is advance

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Couple options that spring to mind (note: I haven't actually implemented these, so no guarantees)

1) use a thunder and set it up as ethrottle#2. This can run a separate target table with any axis input you want (assumes there is a position feedback signal from the VVEL motor) [edit] - just realised the VQ37's ran dual ethrottles already so this is out.

2) A similar external circuit as that used to adapt a 3 wire idle valve to 2 wire control - this would give you the ability to command the VVEL position using a single PWM output with it being converted to push/pull before it hits the VVEL motor (note that this would be open loop control only. I dont think there is an easy way to set it up to match a position target even if you did wire a position sensor back to a separate input)

I would also think that piston to valve clearance is unlikely to be an issue. Pistons dont magically get farther away from valves at high rpm, so your valve lift limits should be the same at all rpm's/loads. The 1x caveat for this is that if you also run VVT cam phasing this does impact clearance, and maybe the OEM ECU only allows full VVEL lift when VVT is above/below certain values. Most OEM's dont build things that will go full grenade because of a single solenoid failure however so i'd be very surprised if valve-piston clearance was an issue at any VVT+VVEL angles. If you are running larger cams then that's another story and you'll have to check carefully.

Have a look at this helpful wiring diagram I found 

http://pdf.textfiles.com/manuals/AUTOMOBILE/NISSAN/g37/ec.pdf (VVEL controller wiring is on page EC-534)

The VVEL control is handled by a separate computer in factory trim. This speaks CAN to the ECU and sniffing + copying this & leaving the controller there is probably the easiest way to control it. Then just create an arbitrary table that determines the "number" to request as a VVEL target angle. Controlling the 2x VVEL modules directly from the ECU essentially requires 2x extra ethrottle drives. 

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Thanks for your reply @cj

1 - I was thinking the same thing when it came to using the throttle control H bridge to control the VVEL but I will be retaining the standard manifold on the VQ37 as it is designed to clear the VVEL motors so I'm stuck with the twin throttle bodys.

2 - This is always a possibility and something that I will have to spend some time researching - Similar to the robotics speed controller. It's really a toss up to see where is the best place to spend all my time. 

The only reason I mentioned the piston to valve clearance is I know Nissan have programmed hard limits into the software when it comes to tuning the VVEL with ECUTek. I agree that you would think they take into consideration these things and would design an engine that would "grenade" like you said. Will do some measurements when I build the engine so I can document the physical clearances.

I have checked out that wiring diagram, the idea of using the factory controller and wiring and using CAN to control them seems like the best option to me. Only issue being I'm not familiar with CAN bus sniffing but it might be a skill set that I'm going to have to learn. Unfortunately I don't have a complete running vehicle / engine, the VQ37 will be transplanted into my Nissan Gloria which currently has a VQ30 in it. 

 

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