VQ37 VVEL Control

[Drexal]

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

[cj]

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. 

[Drexal]

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. 

 

[Cement]

@Drexal Did you ever make and progress with this ? I was just on chat support talking about the exact combo you have (VQ37 and G4+ Thunder). I pointed them towards the Haltech documentation which shows how they deal with the VVEL control, with the factory module over CAN by the looks.

I am just about to start my project (VQ37 in E46) so need to solve the same issue ... hoping to go with a Link (supports 2x DBW but no VVEL) over Haltech (supports VVEL but only single DBW). But would need to swap to cable throttle bodies on the Haltech.

[Adamw]

Probably not in the near future and unlikely with the G4+ platform.  To make this work over CAN we would likely have to buy a car to reverse engineer the system and it is not high enough on the priority list at the moment.

[Zedute]

@Cement have you had any luck coming up with a suitable setup?  I'm installing a VQ37 twin turbo setup in a 1964 EH ute, and running into the same dilemmas trying to find the best ECU to use.  I saw your post on the HP acadamy site too.  I'm tossing up a reprogrammed OEM versus a Haltech Nexus atm.

 

[Cement]

@Zedute I am going to run the stock ECU for the time being as the goal (and budget) is to get mobile first then see where things are at. Unfortunately there were no eureka moments and all aftermarket options came with a significant cost and subsequent tuning effort (i imagine). The Nexus looks like a really great option, especially in the EH as it will take care of all power which isn't in the car at present ... supports twin DBW out of the box also. Are they still using the factory VVEL module with the Nexus like the Elite does ? Seems a bit of a cop out but can totally see why they went this way.

I'm working on running my engine on the ground to prove out my wiring 'solution', spent way too many nights getting to grips with it all from the Nissan FSM's !! Amazing resources to have available ... wish my mysterious BMW had the same

[Zedute]

@Cement thanks mate. I understand I still need to use the factory VVEL module with the Nexus.  Going to be a costly exercise, but I guess if I wanted cheap & easy I would've stuck with an LS1 like everyone else....

good luck with your build.

Cheers.

[Adamw]

Have you guys considered just locking the VVEL at max lift?  Its really only to reduce pumping loses for emmisions isnt it?

[Cement]

I've read a few threads where people have mentioned this, or having a low/mid/high type switch but never heard how they get on. Its really quite a tricky system when you dig into it with some aspects definitely targetted for emissions, however its also attributed to its nice thick torque curve at lower RPM also.

More interestingly they can essentially run without throttle bodies at all and the OEM config implements this to good effect. Read the other day (can't remember where) that at about 13% throttle and upwards they run near wide open throttle blades with the VVEL doing the work ... they snap them closed when you come off the throttle to provide vacuum.

Located the source: http://www.the370z.com/engine-drivetrain/110255-vvel-question-intake-manifold-pressure.html

[Adamw]

Yes, the open throttle is to reduce pumping loses, BMW valvtronic is similar.  I dont think it would make much difference to torque.

[Drexal]

Sorry to be bumping an old thread again guys but I'm slowly looking at moving the Thunder in place of the factory ECU and I'm working out how to drive the VVEL CAN output.

I've started reverse engineering the VVEL controller and I'm able to drive the motors with a CAN output. Is there a way to create a CAN output base on Engine RPM the TPS? Thought I might be able to use a 4D table, either the Fuel or Ign tables that never gets triggered but has the appropriate values to drive the VVEL to where I want it. 

I'm also going to have to do something to control the 7AT via CAN. Guessing there is no easy path for that either?

[Adamw]

Do you just command a desired cam position/lift ratio and the VVEL controller takes care of all the PID, or does the ECU do all the PID and just communicates a forward/back DC to the controller?

Auto trans I would say is a no unless by coincidence they use the same CAN messages as the VQ35 350Z auto.

[Drexal]

Very late response I know, but I'm finally back investigating the Link Thunder running a VQ37 as the factory engine management system just isn't cutting it (Idle, Ignition timing and Fuelling issues). 

 @Adamw - What I know so far is that there is position feedback communicated via CAN with a DI signal for a VVEL abort. Would you have a method to communicate a requested position using the Thunder? Thinking of incorporating an Arduino to do the translation of communication data between the Thunder and VVEL module. 

[Adamw]

On 3/25/2023 at 12:04 AM, Adamw said:

Do you just command a desired cam position/lift ratio and the VVEL controller takes care of all the PID, or does the ECU do all the PID and just communicates a forward/back DC to the controller?