Nissan's version of Toyota's VVTL-i

[dojobi]

I've been doing a bit of reading about the different ways all the manufacturers implement their fancy valve actuation gear, and all the articles I've read seem to concentrate on either the Honda or Toyota implementations. Anyway what I want to know is does Nissan have an engine (preferably turbo'd) with the following features on both the inlet and exhaust cams:

* Continuously variable valve timing (by that I mean opening and closing point adjustment) - if so, how much can it adjust it?

* Control over the duration (most systems I saw only changed when the valves opened, the duration was locked) - if so, how much can it adjust it?

* Variable valve lift - I don't think any manufacturers have *continuously* variable implementations here, but if you know of one, I'd like to hear about it.

I think Toyota's VVTL-i (not VVT-i) does all the above and Honda's i-VTEC is close, but I just wanted to know if Nissan has an engine with it all.

While I'm asking questions, can someone tell me what is the difference between CVTC (Contiuously Variable Timing Control) and NVCS (Nissan Valve-timing Control System)? Both are Nissan systems.

Thanks,

Michael

[dojobi]

While I'm here I might as well ask - the RB26DETT has totally locked cams, right? No control of duration, timing or lift at all?

[prae]

the R34 GT-T's RB25 NEO has variable valve timing

not sure on exact details though

[dojobi]

the R34 GT-T's RB25 NEO has variable valve timing

not sure on exact details though

Yeah, it definitely does. So does the R33 with NVCS. I wonder what the NEO part brings to it though?

Just to add to my first post, I just found a page that described what Toyota's implementation does. It does everything I said above, except it doesn't have continously variable timing on the exhaust camshaft (although they have implemented it in testing - it just didn't help too much, so they left it out for cost reasons) and it can't continuously change the duration on either shaft (although it does change when it goes to the high lift cam profile). So essentially I'm not actually after a Nissan equivalent of this. I want better .

[nmcmahon83]

Who knows... I think it wouldn't be off much benefit on a turbo, most of the Variable Valve timing engines are NA, sothere is obviously a reason why not alot of turbo's use them (probably more to do with cost than anything else as im pretty sure porche have one??)

The later model SR20DET's used VVT, dont know to what capacity...

Probably not much help but im bored

[predator]

The RB25DET uses a basic form of variable valve timing to help with top end and on boost.

The NEO engine uses a more refined version of that which i think why you notice that it gives more across the rev range and why it gives a little better power for each mod you do.

There is also a difference between the RB26DETT and RB25DET that the RB26DETT uses solid lifters that act directly on the valves. The RB25DET uses shims to work on the valves and is slightly less reliable at higher power levels. The SR20DET uses lifters where the cam lobes aren't directly pressing ontop of the valves. I think that is the low-down, anyhow its in the latest Speed mag

Honda VTEC actually has two different cams which it switches between at a certain power band to give a different torque level. Hence why they rev high and get most of their power up high.

I think the Xtrail (and probably others) is starting to use more of Nissans future engine technology using VVTi, and uses a more advanced form of valve timing than seen on the RB25DET NEO or any other Nissan.

The latest stuff they are moving towards is IVVT - which is infinitely variable valve timing, which means the valves themselves are individual actuators, and can be adjusted at any point by the ECU to suit the revs. I think thats how it works anyhow. That will give pretty tremendous levels of power and overall torque from even a relatively low capacity engine. If Honda can get 200kw+ (S2000) out of 2L, in future there are going to be some big power coming out of small capacity non-turbos. And in a way that is one of the reasons why the "fashion" of turbos has largely gone out at the end of the 90's by nissan and many others. Why add a turbo to get more power, if there are other, more efficient ways of doing it..

There are a whole heap of specifics and as usual I usually only take in the general gist - so some of this may be wrong. But that is what the net is for

[SHUTO-BOY]

the sr20 also had a neo version i think

rated at 200hp? not sure

[nmcmahon83]

well the standard S13 SR20DET had 202hp, so i'd hope the NEO had more

[~Hypnotik~]

the sr20 also had a neo version i think

rated at 200hp? not sure

Nope, no Neo version of the SR20. S14 and S15 SR20's (blacktop) had VVT

[red17]

NEO-VVL started in the SR, and as far as i know doesnt even exsist in any other block.

SR16VE, SR20VE were released into the Almera/Pulsar VZR hatchbacks in japan, to directly compete against the Civic Type R in production series. In fact the VZR N1 Pulsar features a SR16VE producing 200hp at the fly with a 6 speed box. Thats a normally aspirated short stroke SR block producing serious numbers!

As far as i am aware the only turbo engine that has been produced with the FULL NEO-VVL system into it is the SR20VET in the X-Trail GT (206kw).

Im not sure about the NEO RB26's but nissans designation for Variable Valve Timing and Lift is "V". If its still got the "D" in it, then its called NEO for some other reason (possibly a new timing only system? compared to the older RB25DET type?)

Its my understanding that all the motors that are designated "D" will only have variable valve TIMING on them only eg: SR20's RB25's.

All the NEO-VVL SR motors have it written on the rocker cover too, not just NEO but NEO-VVL.

[red17]

Its been quite common in recent times in the US for guys to import the SR16VE and 20VE for Sentras.

Heres a link explaining NEO-VVL and the range of motors using it. Note, all of them are SR's

http://www.sr20forum.com/showthread.php?t=18317

Heres a pic of Nissans "Super Pulsar" named later as the VZR-N1 and sold as a motorsport edition to race teams (200 horsies from a 1.6!).

[dojobi]

Thanks for the info guys. I've had a look at the V engines before and they certainly sound good. Does anyone actually have any info on them though apart from just saying that they can control lift as well as timing? ie any specifics? From what I've read the VQxx in the V35 has some different cam stuff going on too, but it hasn't got the V in the name - so I guess it doesn't touch the lift. It might just be more refined implementation of the NEO engines.

red17 - Now that's a Pulsar I really like the SR20VET in the X-Trail too.

predator - so maybe the NEO engines can actually control the duration rather than just the timing?

Now about getting rid of turbos for tricky valve actuation - why not have both? I love turbos for the fat torque curve they give and the easy of modification. I also love an efficient engine and smart valve actuation is a good way of boosting efficiency. Isn't the big problem with the S2000 the fact that it's got no torque? I mean it's a great engine, but just imagine how good it would be if it was boosted.

[red17]

http://autozine.kyul.net/technical_school/...ngine/vvt_1.htm

Not sure if it helps but theres not much info available on NEO-VVL... its mentioned on the second page of that article.

[dojobi]

http://autozine.kyul.net/technical_school/...ngine/vvt_1.htm

Not sure if it helps but theres not much info available on NEO-VVL... its mentioned on the second page of that article.

hehe that's the article I was reading that got me interested in this whole thing. It explains it really well.