cdelena ...... Yes, poorly stated on my part and I am sorry for that.

It is not just the intake, it is the relationship between the intake and exhaust timing that is varied by as much as 25 degrees either positive or negative. The intake valves now face the front of the car (in the case of the RSX) and the engine rotates clockwise. That is a big change from prior generations of front wheel drive VTECs. Yutaka Otobe also mentioned that he was working on the next generation S2000 engine. Our engine also rotates clockwise and would be a perfect candidate for i-VETC in the very near future. I would think from the fuel economy improvements seen with the RSX/i-VTEC that Honda will be moving to upgrade their complete line in the near future. The two things that i-VTEC improves upon is fuel economy and the mid-range power curve. Yes, VTEC is still VTEC and the new i stands for "intelligent" and variable timing which is continuously altered for conditions. And you are right about other manufacturers having variable timing systems, we keep hearing about BMW's VANOS system, I think Toyota also has a VTC system too!

 

yes they do, i think toyota said theirs is the best i think. Their technology is called VVT-I or something.

 

basically carbeurators, nice.

I saw a carbeurated NSX

 

There are a lot of different tricks used by different manufacturers to do variable valve timing. VTEC originally simply switched between two different shaped cams. So you basically had two combinations of timing and cam profile. This isn't really variable timing, but you can have different timing for each cam profile. The big advantage here is that along with the timing you are also changing the duration and lift of the cam, and even how quickly they open and close. Other manufactures have introduced true variable timing, where the same cam profile is always used but the cam is physically rotated to continuously advance or retard timing. So instead of 2 fixed cams profiles you get only 1, but infiite timing control. This gives you unlimited control of the overlap between the intake and exhaust stroke. This is also called variable phasing. Unfortunately by only using one cam profile you can't change the lift or duration, which is a big disadvantage compared to using 2 or more cam profiles. i-VTEC combines these two concepts into one system that gives you 2 cam profiles AND variable timing. Honda is not the only company that does this, but it is as good as anyone else's.

Further along in the evolution of valve control, BMW's new system in the next 7 series is supposed to add real time variable valve lift. I haven't read anything detailed yet about how it works, but it is good enough that the car does not even have a throttle body. Instead, valve lift is just decreased to the point that the enigne idles on it's own. If this works as advertised it would also mean that BMW should be able to adjust lift depending on throttle input as you drive. Currently, cars have cams that are designed for WOT operation and aren't ideal for partial throttle operation. Someday we will have full computer control of valve operation and all this technology will be instantly out of date, but for now this sounds like it is as close as it comes in production cars. If anyone has any links to technical info on the 7 series engine I would really appreciate a post. Sounds very cool.