My roommate and I were talking about his Scion tC and he wanted to know the difference between the following and could you please explain what they do?

Toyota's VVTi and VVTL-i and Honda's VTEC and i-VTEC

 

They vary valve timing.

 

Well I'll share what I got... Honda VTEC is the ability to switch to 2 diffrent CAM profiles, one for low rpm and one for high rpm. i-VTEC impoves upon that with, I believe, continual variable of the CAM profiles through the RPM range.

 

I read about it once. And I believe that toyota does more with the air flow. Variable intake something or other.

 

they are almost the same. lots of car manufacturers have VVT variable valve timing. is one better than the other? theres no yes or no answer. VVT can be used to save gas or in other cases waste it.

 

VVTi is similar to VTEC

VVTLi is similar to iVTEC


...to the best of my knowledge

 

VVL (predecessor to VVTL) and VTEC are similar. i-VTEC and VVTL-i are similar. They're not all that different from each other.

 

Here's what I remember.

VVT - i advances or retards the camshaft only. It does not switch cam lobes at any point in the rev band.

VVTL-i is truly akin to our i-VTEC.
It advances and retards the camshafts, and the camshafts have a secondary cam profile, to which it switches at around 6k rpm in most applications.

The mechanics of how the switch takes place are subtly different from the system Honda uses, but the basics forces are pretty much the same.

h: There ya go.

 

then who is it that varies intake pressure?
am i retarded?

 

Actually IIRC either the GSR or the Type-R have some sort of variable intake manifold.