# Why nissan didn't vtec?



## PrinceMS (May 25, 2004)

*Why nissan don't vtec?*

i am just curious why nissan has not introduce VTEC technology in their line of product? Even GM cars have eco-tec? (or whatever its called). 

Yes, I agree that nissan engines are v.powerful and solid and don't really need VTEC (or any of its variation) but other than that what is the logic of nissan behind their dicision to not to incorporate VTEC technology?


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## Radioaktiv (Feb 12, 2004)

umm they do
read up
http://www.nissanforums.com/forumdisplay.php?f=138


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## Nismo1997 (Dec 26, 2003)

they got sr16ve, sr20ve and and even vet


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## PrinceMS (May 25, 2004)

I was thinking in the line of maxima actually ...
i was hopign for little detailed answer so i guess i will ask direct Q:

- Does vtec/VVL reduces the reliability or bad for engine somehow?
- Does vtec/vvl require 2 different cam set or is vvl/vtec is just advance timming of same cams in the engine?


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## psuLemon (Apr 23, 2003)

every car has its own little vtec... we have the vvl, the vtc.. but vtec motors, mean you have no torque..


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## ReVerm (Jan 13, 2003)

PrinceMS said:


> I was thinking in the line of maxima actually ...
> i was hopign for little detailed answer so i guess i will ask direct Q:
> 
> - Does vtec/VVL reduces the reliability or bad for engine somehow?
> - Does vtec/vvl require 2 different cam set or is vvl/vtec is just advance timming of same cams in the engine?


For starters, take a look at the information on these pages:
http://www.billzilla.org/vvtvtec.htm

It's a comparison between Honda VTEC and Toyota VVTL-i, but it should give you a good idea of what these cam switching technologies actually do.


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## Nizmodore (May 9, 2003)

All Vtec is is variable lift, variable cam timeing and secondary throttle plates....hell its been done to death!


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## Ninety-Nine SE-L (May 5, 2002)

There's variable cam timing and variable valve lift, 2 different things. 

Honda's VTEC is mostly variable valve lift where the cams switch to a more "extreme" lobe geometry at a specific RPM.

GM's eco-tech, I believe, is variable valve timing which is just the intake cam advancing or retarding in timing to allow more or less overlap. I believe Toyots uses this too, but I can't remember what it's called.

Nissan actually uses both in a few of their engines. I believe most SR20s have variable valve timing, not quite sure. Many of the newer nissan engines like the VQ and the QR use CVTCS (Constant variable timing control system), it's in the new SE-R, Altima, Maxima, and Z.

Nissan also uses their NEO-VVL system on a few models outside the U.S. The SR16VE and SR20VEs use the variable valve lift (just like VTEC) and one thing it also has over honda is torque.

Anyway, please familiarize VVL with VTC


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## niky (Jul 20, 2002)

The old GA16DEs had VTC. 



Nizmodore said:


> All Vtec is is variable lift, variable cam timeing and secondary throttle plates....hell its been done to death!


Variable lift and Variable timing HAVE been done to death, but no one does it quite like Honda. 

But no one does turbo quite like Nissan.


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## James (Apr 29, 2002)

Ninety-Nine SE-L said:


> There's variable cam timing and variable valve lift, 2 different things.
> 
> Honda's VTEC is mostly variable valve lift where the cams switch to a more "extreme" lobe geometry at a specific RPM.
> 
> ...


SR20VE's have variable valve timing. Outsideof that only later model sr20det's had some sort of cam phase adjustment, normal sr20de i've never seen any form of either.


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## chimmike (Oct 17, 2002)

iirc GM's eco-tech is just the name of their engine.......they've had it for like 5-10 years in the cavalier...kinda like a dodge magnum engine.


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## James (Apr 29, 2002)

yeah I don't think GM has any form of it but then again, I could care less.

Ford had it in there Zetec engine, maybe that's what he meant. They had variable cam phase in their exhaust cam only for emissions reasons not for power.

BMW it seems is the master of Variable lift/timing though, not Honda.


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## Zombie Elvis (Jun 21, 2004)

James said:


> SR20VE's have variable valve timing. Outsideof that only later model sr20det's had some sort of cam phase adjustment, normal sr20de i've never seen any form of either.


Yup - the SR20DET on the S14 and S15 Silvias has an intake advance which depends on ... umm .... I saw the service manual once. No wait, I'm fairly sure the GA16 also has it, as fitted to australian cars at least.

It uses oil pressure and a simple decision (probably in the engine management) to push the intake cams a few degrees to shift the torque curve up or down the rev range. Sorry I can't be more specific but my puslar service manuals are buried somewhere. The effect is to get the max torque at the point where it's most useful when you are demanding power. When you back off it switches to the most economical cam angle.

The settings are between two fixed cam angles because of the simple oil-pressure system. I think it actually pushes the cam to the left or right so that the lifters act earier or something like that.

If you (original poster) reply with interest in more information I'll dig up my service manuals and write up the real facts.

This system is not to be confused with the more sophisticated system in the *VE model engines.


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