what does a vtec do

[dtm]

i think the reason why a cold engine will not engage vtec is because the oils viscosity is too high when cold... i.e. the resistance for the oil to flow is very high and its harder to push through narrow gaps (and little valves)

oils viscosity drops considerably with increasing temperature.

i could be wrong on this however but im sure it has something got to do with it.

 

[JohnBoyWalton]

Engagement is dependant on engine temperature as well as oil pressure.
ie. If the temperature gauge is below the bottom tick, VTEC will not work. Safety feature. Your oil could be hot and have correct pressure cos you've been driving for an hour, but thermostat is stuck open so the engine temp doesn't heat up, vtec will not work.

 

[Adam]

Also - the car has to be in gear and travelling over a certain speed from what Ive read and tried.

 

[Gaz]

And also ...................... ............ if you ever disconnect your speedo for any reason, it won't engage vtec either. In my last Civic VTi I took the speedo out one time to add some chrome gauages etc but accidentally broke the clip on one of the cables, took me a couple of days to get a replacement from Honda in which time I discovered there was no va va vtec

Gaz

 

[peter_261]

iv heard u can run the v-tech on just the lairy cam an they go better.But THAT party piece is nifty!

 

[PaulYDP]

iv heard u can run the v-tech on just the lairy cam an they go better.But THAT party piece is nifty!

All sorts of tricks u can do with them old computers!! 8)