what is vvt/vvti/dvvt on toyota car

[EDRA]

actually i a bit confuse about this thing. can zth member explain about this.

 

[scomatic]

I hope i can help you explain,
VVT is allows the lift or duration or timing of the intake or exhaust valves to be changed while the engine is in operation.
Example:
http://www.youtube.com/watch?v=mgDdbrMh6bo&feature=related

DVVT is same as VVT but it adjusts both intake and exhaust camshafts
example:
http://www.youtube.com/watch?v=zpERYiHR0NU&feature=related
Chinese explain:
http://www.youtube.com/watch?v=6AXh8O7hWU4&feature=related

VVTi is an adjusting the valve timing engine start and stop occurs virtually unnoticeably at minimum compression. In addition fast heating of the catalytic converter to its light-off temperature is possible thereby reducing hydrocarbon emissions considerably.
example:
http://www.youtube.com/watch?v=MR63IrKHv7E&NR=1

 

[antue]

nice information...

 

[EDRA]

thanks for ur info.

 

[Barbarian]

vvt doesn't change the lift and duration..... it changes the timing.... this allows over lapping of the intake and exhaust valve opening/closing hence helps flow of air....

 

[suma_]

from wikipedia http://en.wikipedia.org/wiki/VVT-i

My silly question:
Is the newer version ZZ-FE series/VVT-i system can be used in 4age-20V?

Cos - I'm annoyed with the VVT pulley noises

 

[NA_Lover]

Hmm.. according to some drivers..
modding the VVT cam to an aftermarket unit will remove the VVT clanking noise completely.

Of course, I havent tried it. But I believe it works.
This is because on the stock VVT camgear, the moving mechanism is free to rotate during idling.

Another alternative I heard; is by soldering the VVT mechanism to avoid it from moving at all.
But this probably means VVT will be on ALL THE TIME on your machine.. even during idling..

Correct me if I'm wrong k..

 

[kennix]

Erm...if the lift is too much and duration too high...i think you can't use the VVT pulley anymore..

Stock stock can use up to 272 degree cams with VVT remain. Of course the lift is 8.xx if not mistaken. Anyone to enlighten this??? Correct me if I'm wrong.

 

[Barbarian]

not ture.... my lift is 11.1.... and my vvt works perfectly well....

soldering the cam gear means disabling the vvt... so you won't have the vvt sound and you won't have vvt as well.... some ppl do that when they go FI to avoid valve overlap....