when does it kick in?

 

Oh really?

 

huh?

tcs kicks in when the system senses a slip in the tires.
vdc helps keep the car under control by cutting power/breaking individual wheels.

 

Continuously Variable Transmission? Is that what you mean? I don't think the Z has this. Look at what camaro194 said

 

The op is referring to CVTCS (the variable valve timing system on the VQ35). Nissan designed the system to crossover seamlessly into its higher lift/duration cam lobe. It does not feel like a classic "VTEC" crossover which is actually a good thing. CVTCS feels like it changes over depending on throttle position and oil pressure instead of just a set rpm mark like VTEC.

 

It crosses over gradually in a linear fashion from 3000 to redline. You can't feel it. You can hear it though, exhaust note changes.

 

Ahhhh, now I see what he was referring to. Forgot all about that one. I guess without a popular name like 'VTEC', its easy for one to forget about it

 

you guys have it all wrong, jebus christo.

First, in order to not sound like a douchehat (not directed at ANYONE in particular) when asking the question......find out what CVTCS stands for:

CONTINUOUSLY VARIABLE TIMING CONTROL SYSTEM

Now, by standard logical deduction, you can see that there is no vtec-like changeouver......because it is continuously variable. Unlike previous gens of VTC in Nissans, the CVTCS is continuosly variable cam timing based on throttle position and load. You will never 'feel' it activate, ever, because it's always working.

 

You are somewhat off on the VTEC remark. I am only trying to inform, so please, don't take this the wrong way.

VTEC has had varying stages of being engaged throughout the years. My 95 GS-R, for example, came on at 4400 RPM, but only if the engine was warmed to operating temp., the oil pressure and coolant were checked and where they needed to be as verified by the computer, and only when you were above a certain accelerator angle (don't remember the exact angle). Then, at 5700 RPM, the butterfly valve in the intake tract opened up so the air would follow the "short", high-speed path, creating more power.

On a 97 Type-R, though, the VTEC did kick in (I believe it was around 5600 RPM, but I am not sure of the exact engine speed, it kicked in later thanks to OBD2 and emissions) as soon as you hit the RPM "x-over", triggering the hot cams. It didn't matter how hot or cold the engine was, didn't bother to check oil pressure, and didn't care about the throttle angle. It was an on/off "switch".

Now, to clarify, my GS-R did basically have a "switch" itself, but only under full throttle acceleration (or at least past the throttle angle), after the engine was warm, and so long as I kept the oil changed and full (which I did).

The VTEC system has other variations, as well, most of which are economy-based systems. In addition, older Civic EX's had VTEC, but only on the intake cam, with very little lift and at a higher RPM. It (and most VTEC systems) checked similar to my Integra before it would engage. Base RSX's also have i-VTEC, only on the intake side.

I only point this out because VTEC didn't work like a switch to begin with and has evolved just as much as other variable valve timing systems (Honda did invent it, after all). Most VTEC systems are extremely linear in power delivery now, and the "pop" is much less drastic, as is the banshee shriek that follows from an aftermarket exhaust.

Just trying to keep peoples knowledge accurate.

 

If you're talking about variable intake cam timing, it kicks in around 4000rpm at WOT.

Since the revup has variable timing on the exhaust, I'm not sure where that kicks in since I don't have a revup.

 

Having owned/built/raced many hondas i know all about it. I was only trying to keep the terminology simple for the op. The way he mentioned it "kicking in" led me to believe he was familiar with the classic crossover VTEC.

 

Sorry, Zreign. Sometimes I know too much trivial information for my own good.

 

Dear God this thread is full of misinfo....


1. The VQ35DE uses a cam phasing type of variable valve timing where the intake valve opening and closing is changed relative to the crankshaft. The lift and duration is unchanged.

2. VTEC uses a cam changing type of vvt where there is a seperate high-lift/high-duration cam lobe and is activated at a set RPM.

3. With the nissan CVTC The intake cams are almost constantly changing position depending on RPM, throttle application, MAF voltage, etc. It doesn't start moving at a certain RPM.

 

True, but if you see my post, you'll see where it kicks in around 4000rpm if you are at WOT.

At partial throttle it's a different story, but who cares...

 

What's your definition of kicks in? Just because the cam timing curve is relatively flat until then doesn't mean it "kicks in". CVTC is always working. The point is, the OP thinks that the VQ35 CVTC system operates like VTEC and kicks in at a certain RPM. That is erroneous.

And yea i read your thread. I made a few informative posts in there.

 

Floor your Z in 2nd and feel the "kick in" at 4000 that Wired is talking about. True, CVTCS is always working but it does work under set perameters (like timing the motor for top end hp when hitting 4000 at full throttle).