Thread: engine swap
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Old 01-30-2007, 09:17 AM
  #7  
mberndt
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Originally Posted by WhiteNoiz
5250 rpm is about where it kicks in, at least in my 5th gen. I guess you could call it a turbo feeling. More of a vtec feeling. its rad, people shift when you vtec lol. (typicly)
Actually, it has nothing in common with a "turbo feeling"...
And since you are a Honda owner, you should understand the operation of VTEC... One of my pet-peeves ...
VTEC simply extends the torque curve beyond the operating range of most motors. This extension equates to high HP cause of the definition of the function of Horsepower. It is dependent upon the torque and RPM.

It is nothing more than the ability of the motor to use 2 different camshafts for 2 different engine speeds, that's it. Period.
If the engine only had the cam with the large lobes operating all the time, it would only make power high in the rpm band. and Vice-versa.

And VTEC is fundamentally different than other manufacturers' Valve-timing systems. Only Honda, Toyota (Celica GTS) and BMW have developed systems where BOTH the valve timing AND more importantly the valve lift and duration are changed in response to engine speed.
And it is this large lift and duration that enable power to be generated where other engines would simply not be able to flow enough air. Also, the tell-tale VTEC sound is because the overlap of the valves...
What you "feel" is the difference in the torque when the high-lift cams begin to operate. In fact, if it is done properly, it will not "feel" like anything more than a smooth transition. (I've heard Honda purposely made the RSX X-over point higher in order to "make it feel" like a bigger jump).