Originally Posted by 700bones

Also, take there is the fact that EGR was removed from the VVTi engines a couple of years after their intro, which speaks for itself. VVTi works well on controlling the emissions, so EGR was not needed.

Originally Posted by alien1974

I am confused here, does my 1998 uk ls400 vvti have no egr pipe?

Originally Posted by 700bones

That's non-sequitor.

The VVTi are engineered to make more power BECAUSE the VVTi does a good job controlling emissions. The power increase comes from things like you have already said - better flowing intake, etc. If the engines do not pass emissions, they aren't going allowed to go to market. It isn't the VVTi which CAUSES the power increase.

People have tuned non vvti engines to make just as much or more power than the later VVTi engines, by doing similar mods -- intake, porting and polishing to make the non-vvti flow as good as the redesigned vvti heads, etc. I'd rather not post links because I don't know your rules about that here (don't know about specific rivalries, what you consider "advertising" etc). But if people search for it, they can find 290 HP in NA non-vvti is easily obtainable. It probably won't pass CA or other emissions, but it's doable.

Also, take there is the fact that EGR was removed from the VVTi engines a couple of years after their intro, which speaks for itself. VVTi works well on controlling the emissions, so EGR was not needed.

Originally Posted by Stroock639

while vvt-i may be there more for emissions, it's wrong to say that variable valve timing does nothing for increased power. under high load at low rpms the intake valves close earlier, improving volumetric efficiency and cooling down the combustion chamber which makes more low end torque (just look at the torque curves in that graph they're noticeably different). while it's not necessarily vvti, vtec makes a longer intake cam profile when it activates at high rpm. when it activates you can literally feel the car pull slightly harder

Originally Posted by 700bones

VVTi and Honda's VTEC are completely different technologies, respectfully.