all good and nice but remember that the rsx was faster, is faster and forever will be faster. the end.

 

With Nissan now using electromagnetic valve timing adjustment, I imagine they would have incorporated this into the new VVEL management as well, don't you think?
Who would possibly have access to this new ecu, the engine isn't even in production yet- is it? Did I miss something, because I was under the impression we wouldn't see this until the next Z and maybe the new G35 coupe due next year.
Will

 

 

Well, that's good to know regarding the presence of VTC. It was a no brainer really. I only got concerned because there were no mentions of it in any current publications of the VHR.

With 11mm of lift and 300* of duration ... that is adequate for most aftermarket use other than for particular extreme cases. Just about the only other thing that would be beneficial is duration profiling, which can only be altered by the shape of the driving cam. The rest is all ECU work. Man the possibilities are making our 35DE neolithic at best.

 

 

Will,
The electromagnetic VTC from the VQ35HR is a stepper, on or off. Regular VTC is hydaulically accuated with infinite steps in operation. Reading in between lines, I recon Nissan switched to the electromagnetic version for the exhuast side sighting heat related accuracy issues w. the hydraulic variety. Infinite step hydraulic VTC is still used on the intake side.

If they're gunning for a late 07 release, the engines will surely have alrady begun prelim production. There's always the few that have insider information (namely some of the JDM's best tuners).

 

I see. It makes sense about the heat affecting the hydraulic actuation, but I assumed the electromagnetic activation had some variability based on current. Obviously, I have not really looked into the newer VQ's operation. Although now it seems why even bother, as the VHR is on the horizen. Man, my DE now seems to be as antiquated as the OHV engine in my truck.
The ECU thing surprises me, as there were a number of copanies very close to Nissan trying to crack the Z33 ecu when it came out, but to no avail. JWT being one of them. To have the ecu for this new VQ, with so much potential in a reprogram, in the hands of tuners so soon seems unlikely to me. Unless this is the basis for the engine in the upcoming GT-R. In which case the heritage of that car has a great deal to do with it's aftermarket support- and it makes some sense that Nissan would want to keep that aspect of the car's allure alive in the new generation.
Will

 

If i remember correctly, it employed an electromagnetic clutch type unit, so it would be capable of only two states - advanced or retarded.

ECU inners are well guarded by all car manufacturers. Nissan in particular. With the advan of ever more secure electronics, it's becoming far more difficult for people to crack. Gone are the EPROM days. Our ECU is made by Renesas (formerlly Hitachi). The same type of ECU also powers the Mistu EVO and Subbie STi. Those two have been cracked wideeeeee open these days and I suspect w. lots of "inside" help. Nissan seemed to have faired better in that regard. Even that's starting to change with companies like UpRev and Cobb Engineering.

I don't think JWT has the Z33 ECU broken even now. They simply purchased the Tectom programer (distributed by TechnoSquare) and have since done away w. the direct ECU tuning approach for their TT kit. They settled for a custom piggyback at the end. Tectom of Japan was the one that broke the scene first. I also suspect they had some inside help.

 

What if instead of a solenoid to actuate the valve a stepper motor was instead used? Granted heat is still a consideration but it should have a more linear response to inputs then a solenoid. Although I wonder if a stepper motor could react quickly enough to be effective. HKS seems to think so in their EVC boost controllers but its a much different system its controlling...

 

The basics of a solenoid is no different than a stepper motor, that is they are all electromagnetically driven. The same fundamental limitation exists. A solenoid is essentially a linear motor, as it is sometimes referred to. The biggest hurdles already brought up is the valvetrain moment of inertia. The engergy required to stop and then reverse the direction is increase by the square of the speed (derived as rpm). Like everything ... mass kills!

 

No, JWT hasn't. Considering how much of their business was tied up in Clark's Z32 and SR20 ecu reprogramming, they really wanted to carry that into the Z33. The flash they picked up from Tadashi at Technosquare was never going to do the job everyone thought it evntually would. I always figured if anyone in the US would crack the Z33 ecu, it would be JWT. Since they have to use a piggy back on their own kit, I guess it's fair to say we aren't going to be able to run reprogrammed ecu's here in the States anytime soon. The controllers are getting far too sophisticated and proprietary.
Will

 

Isn't the VTC solenoid pulsewidth modulated to advance or retard the timing? It's never really resting on a stopper pin until it goes full retard to 0 degrees at higher rpm.. I suppose it's square wave?

 

They're making baby steps with it.. but, Clark hasn't been able to directly modify all areas of the ECU.. They won't release a product unless it's 100% though..

 

From what I was told.. the GTR and G37 ECU architecture is almost identical.. especially in the areas that count the most for what we would be interested in doing.

 

Hey I fully thought and expected the same from JWT, but it just didn't pan out that way. I can definitely understand why after working w. that Tectom tool and what limited info was supplied. I was in the process of decompiling our ECU more than a year back. It just wasn't worth my time after a while, so I abandoned it.

The UpRev folks seems to have a lot more figured out these days. They of course are keeping them fairly proprietary. We as a community need a break through like the EVO/STi folks. Yay to open source!

 

That is the case for the hydaulic driven VTC. The pulsewidth regulates the hydraulic pressure, which has an effect on the VTC offset angle. This I know for a fact.

I do not however know exactly the inner workings of the electromagnetic variety. It was speculated, although NOT confirmed, that it was a two-step version ... so I have read. I'll have to dig into the '07 service manual for this one when I get home.

 

Alright, I just search through the service manual and verified EVTC is in fact continuous.
That's would seem to make a lot more sense than taking a step back from VQ35DE-revup's exhaust continous VTC .

Excerpt from the service manual:

 

If you've talked to them, let me ask you- do you think they will have the Z33 ecu cracked and able to program to the same extent as their SR abilities? Is this their goal? With the list of stand-alones and piggyback controlers increasing every year, I would still prefer to have the stock ecu tweaked for mods rather than the alternative. I know JWT more often than not tunes on the safe side for numbers, but hassle-free and reliable is a huge plus with their SR tunes.
Will

 

Using current to control the hydraulic pressure on the intake side of things via a solenoid is old hat, this electromagnetic system I think has more possibility than meets the eye. Thinking about it more, the oil flow really wouldn't be so affected by the exhaust heat with the actuator being on the front cover, and flowing at a high rate through the system. I don't think it would have any detrimental viscous change due to heat from the exhaust side. I imagine the real benefit to the eCVTC is the lower parasitic loss. No chain, lighter components on the camshaft, lower profile- less mass is always better. Your service manual doesn't give total phase range on timing advance and retard. I imagine being the first system it is not sophisticated enough to offer the range the hydraulic unit can. But, with this new VVEL, I imagine the materials and actuation have improved to the point of being more favorable than the hydraulic action. Maybe a complete removal of the timing chain except to drive the water pump, which would be just a... pump chain? I don't know, but with the throttle plate itself not being a primary need anymore, electronic actuation of the valvetrain for both timing and lift is the new electronic throttle. If not on the VQ37VHR, then soon I would say, the timing chain will be obsolete, and the accelerator -having already lost the tether of a cable to open a throttle plate- will now be electronically tied to the ecu to directly open the valves with full electronic control of the valvetrain.
Will

 

You're getting ahead of yourself there w. the EVTC. The mechanism still works in the same fashion as it's hydraulic cousin. From the outside, it even looks virtually the same. Both are still part of the cam sprocket and driven by a chain. The service manual does show the range of operation to be comparible to the hydraulic variant. Parasidic loss is not an issue in regards to how these VTC work. I'm not certain why Nissan's chose to retrofit the hydraulic unit with the electromagnetic unit on only the exhaust end. It could be for tighter control to better stay withing emission standards.


That is exactly how the VVEL as well as Valvetronic works. ECU is indeed driving the valvetrain directly. The butterfly is just there and it's not going away anytime soon. Emission standards requires it there to prevent EGR/EVAP fumes from venting through the intake.

Timing chain is in fact obsolete in this case, if not at least for the Valvetronic engines. There's only one belt that drives the ancilliaries.