i heard that 2004 model of the s2000 might have i-vtec, i've searched on the difference between vtec and i-vtec but there wasn't anything relating to it, so i was wonder wats the difference.

 

I-VTEC is infinitely variable, instead of having a hi and low setting it changes dynamically throughout the RPM range.

 

I-VTEC still just has 2 cam profiles for lift and duration just like VTEC. The difference is that valve timing is continuously variable, so the cams can be advanced or retarded by the ECU.

 

My bad.

Explained here:
http://www.canadiandriver.com/articles/jk/...11205.htm&e=912

 

And technology aside, some would say the transition is felt more when jumping to VTEC than in a car jumping into i-VTEC, the variable valve timing across the rev range smoothes out the transition.

 

advantages: torque curve starts earlier and remains flat, more potential in peak power output.

disadvantages: more circulating mass...some speculate a higher rate of failure to traditional VTEC in endurance racing.

 

I never thought about the additional weight of the valve timing gear that's under ecu control, but other companies such as BMW has been running near-indentical technology in racing for years w/ success (VANOS). Most other brands have some sort of VTC...Honda's more unique in that it has variable cam profiles.

 

Honda doesn't have variable cam profiles. There are 3 discrete profiles for intake, and 3 discrete profiles for exhaust. Two of the profiles are very similar (Primary & Secondary non-VTEC) and the other is the aggressive VTEC profile.