Difference between Vtec and I-vtec?
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From: New Jersey
Re: Difference between Vtec and I-vtec? (standbackimapro)
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Joined: Apr 2007
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From: Closed For Remodeling, MI
Got this off of an RSX forum. The grammar, and punctuation are a bit suspect but I think it gets the point across.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">Vtec= LIft and duration of the valves at a set RPM.
The car drives on a lower(emission//econimy) cam profile at lower rmps and when Vtec is engaged it switch to a highperformance Cam profile making the valves open more and for longer.
it is simply a regular cam has 1 lobe per valve. the use all time
the vtec has 2. the middle lobe is used by 2 valves when vtec kicks in
http://www.todaracing.com/imag...s.jpg
http://www.todaracing.com/imag...r.jpg
The i in vtec Adjust the cam timing the advance and retard. think of it as a cam pulley like on the prelude to get 15/-15 timing you have to buy camshaftpulleys and set them on a dyno to get the most out of the engine right. well on the i-vtec its 50/-50 and its controll by CPU so its adjust constant while driving. It is more of a emission Issue than performance but in America where the emission on imported cars are so strick Honda and othe companies just got away with it again/ the BMW M3 had i-vtec before RSX just call different and the mechanincs are somewhat different.</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">Vtec= LIft and duration of the valves at a set RPM.
The car drives on a lower(emission//econimy) cam profile at lower rmps and when Vtec is engaged it switch to a highperformance Cam profile making the valves open more and for longer.
it is simply a regular cam has 1 lobe per valve. the use all time
the vtec has 2. the middle lobe is used by 2 valves when vtec kicks in
http://www.todaracing.com/imag...s.jpg
http://www.todaracing.com/imag...r.jpg
The i in vtec Adjust the cam timing the advance and retard. think of it as a cam pulley like on the prelude to get 15/-15 timing you have to buy camshaftpulleys and set them on a dyno to get the most out of the engine right. well on the i-vtec its 50/-50 and its controll by CPU so its adjust constant while driving. It is more of a emission Issue than performance but in America where the emission on imported cars are so strick Honda and othe companies just got away with it again/ the BMW M3 had i-vtec before RSX just call different and the mechanincs are somewhat different.</TD></TR></TABLE>
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