I know that Vtec need a few factors present to engage. I know it need oil pressure, a warm engine, and a set RPM reading (based on your ECU), but does throttle position matter if the above-mentioned factors are there? Say you're cruising downhill at 6krpm but you're not on the throttle. Will Vtec be engaged the entire time or will the primary cam lobes be used once again until the necessary throttle position is reached?

 

yessir it does, there is a certain throttle postition neccessary for VTEC

 

Yup, TPS reference is needed... Don't forget about VSS too...

 

Anyone know the degree or percent of total rotation the throttle butterfly has to be for Vtec to engage?

 

map sensor, ECT, and RPM singals - These are the factors that determine vtec switch over. I don't remember vss nor tp as input for vtec operation; I guess during Honda's technicial training on vtec operations - I was sleeping.

 

Yes those are all correct (I have never ONCE heard of MAP tho) but just as everyone has said, TPS reference and VSS (car has to be rolling) are factors...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kataku2K3 &raquo;</TD></TR><TR><TD CLASS="quote">Yes those are all correct (I have never ONCE heard of MAP tho) but just as everyone has said, TPS reference and VSS (car has to be rolling) are factors...</TD></TR></TABLE>

The ECU/PCM looks at engine load(map), engine temp(ect) and RPM singal.

If the ECU senses load and RPM singal - No reason to use tp nor vss singal. Maybe your right and honda trainers just forgot to mention TP and vss as factor to vtec operation.

 

i belive it need to be at least 50% to engage at 5800 but once you are engaged , it has to drop below10% And/Or 5400rpms to disengage... at least thats how i thappens in my ex... hope that helps out some