VVEL control unlocked

Nissanboy

I don't see how this could improve power on NA applications as the intake lift is already at it's maximum point (goes from 2mm to 11m lift) because of the eccentric cam being only so big on the VVEL ladder assembly and the overlap being precise as the rpms go up. I could see some very impressive gains on FI applications as everyone has already stated. Just like to give out my point of view

Jordo!

I seem to recall an old chart from another forum that showed there was more lift possible...

I'll see if I can find the image and post it.

EDIT:

Here...

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Rusty

So that chart is saying max is about .500" lift. But it's only using up to .450" lift. HMMMMMM You know how much duration there is?

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Nissanboy

Where did you get that chart if you don't mind me asking?
Reason being is I've taken several Nissan courses (Currently a Nissan Tech) and they've always stated that the max lift is 11mm due to the eccentric cam only being to big. I'm not trying to say that I'm correct or anything, I'm just wondering why they wouldn't of mentioned it.

Another reason being is if there is more lift available, why did they not implement it into the power band? Only reason I could see why not is because our motors being interference motors it could cause a clash between the piston and the valves.

Jordo!

A site that shall remain nameless under pain of excommunication around here...

google VVEL and 370Z in images and it will pop up on the first page

EDIT: Whoops -- it just links back to another thread on here. I'll shoot you a PM.


I'm guessing because of the same factors that result in other tuning limits -- gas mileage and emissions. I find it hard to believe there's no wiggle room left.

Even with ignition timing, where there is not much room for advance, a couple of extra degrees can be safely dialed in, and that nets in reasonable power gains.

I find it hard to believe the valve timing is optimized for power and any other changes result in valves hitting the pistons or power loss. If the tolerances were THAT tight, it means that with just a little valve float at high revs, you'd see mushroomed valves occurring here and there, and I haven't heard of a single failure like that, even though most people bump up the rev limit by a few hundred RPM and plenty of people beat on the car.

Moreover, even if timing and overlap is optimized when stock, slap on a free flowing exhaust, different IM or set of headers and its (potentially) a different ball game.

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Nissanboy

I agree but one thing that people seem to misunderstand around here is just because something is used to provide better emissions and gas mileage doesn't mean it has been made only for that. Think about it; if the hydrocarbons in the air-fuel mixture is burned better or more complete, it will give us better gas mileage, emissions AND power. Just simply increasing the efficiency of the motor.

BigT

Has anyone thought of our valvesprings? Can they handle any more lift, duration, and romp rate?

Nixlimited

I always thought the issue with springs was the decompression side rather than the compression side (e.g. float).

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Rusty

Also coil bind.

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Jordo!

All empirical questions -- hopefully uprev has at least one or two motors they can risk destroying to find the limits...

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Japanjay

That is why once VVEL cracking is finally done, the market for aftermarket parts opens wide for head work and parts. Valves, springs, retainers, manifolds, etc....

Jordo!

Good point!


But as with every other parameter, I'd be surprised if Nissan left nothing on the table in terms of VVEL tuning.

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edub370

very likely. since IMO the vq has gone as far as it can in terms of performance. nissan has squeezed everything they can outta this engine platform

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Rusty

I think if Nissan wants more out of this engine package. They will have to give it a bigger bore, a shorter stroke, and a higher red line. The goal should be 100hp per liter. IMO

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Jordo!

If they had there'd be no point in bolt-ons and tuning.

Valve timing and lift affect emissions as well as peak torque -- the NA gains may turn out to be modest, but I get they are there for the taking.

If another hr on the dyno playing with VVEL could net even another 5-7 whp at various points in the rev range, I'll take it.

I'm still fairly convinced that VVEL tuning is part of why Nismos tend to dyno a bit higher.

EDIT: ^^^^ apparently, I was completely wrong on this one! See further here ECU ; stock ECU Vs Nismo ECU difference

Guess it was really just the exhaust -- SH0velman was correct!

Also, I can indeed confirm that the H-pipe Nismo take off exhaust makes good power and is superior to the Weldina Y-pipe Nismo cat-back.

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