imported_BoOsTd

found this little write up on Vtec, got it
here http://www.pistonheads.com/doc.asp?c=120&i=5155


I was impressed by the different tehnical explination unlike most others where it just explains that the "bigger cam kiks in and the head breathes better" over 5500 triggered by a solonid.

heres alittle more technical explination that i found was easy to picture whats really happening inside that head.

vtec:

Of course without some form of forced induction, getting such high power outputs from just two litres requires high revs, which in turn requires cams with high lift and long duration to provide sufficient valve opening to allow the engine to draw in large amounts of air/fuel mix. Great at high revs but crap at low revs, which is a real problem for a road car - or would be without Honda's ingenious VTEC system, which works by literally having two camshafts in one, with three cams (two mild ones sandwiching a central wild one) for each pair of valves.

In normal running the mild cams do the work, operating the valves via rocker arms just like with an ordinary 16-valve engine. The clever bit happens around 5850rpm when pins lock the previously redundant central rocker arm to the two outer ones, at which point the valves are then controlled by the high lift, long duration cam, providing the improved breathing the engine needs to run at high revs. And in the S2000's case high revs means a mind-boggling 9000rpm.




To some this isnt new info im sure, but for everone else i think its a good way of picturing it.

bbarbulo

iTrader: (2)

haha... my brother did his honors paper for mechanical engineering on variable valve timing... I'm sure he didn't put "kamz kick in like whoa" in his report

imported_BoOsTd

LOL, its just mad vtec yo, who needs to know how it works! it just magically gives a zillion hp over 6,000 haha