Jump to content
SAU Community

Recommended Posts

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

Link to comment
https://www.sau.com.au/forums/topic/35210-nissans-version-of-toyotas-vvtl-i/
Share on other sites

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 :D.

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 :D

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 :D

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 :D

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.

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!).

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 :D 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.

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
    • I'm not going to recommend an EBC pad. I don't like them. Just about anything else would suit me better. I've been using Intima pads for a while now.
×
×
  • Create New...