I don't know where people come up with this kind of misinformation, but I've seen this one twice now, and it's time to put it to rest.

Some people have gotten the mistaken impression that the AP1's don't engage VTEC until 6,500 RPM, and that's just WRONG.

We need a special forum just for the people who make this kind of sttuff up.

Things here are changing, and I'm concerned that the current best advice might be to assume that anything you read here on S2kI is wrong, becaue of the way the quality of so many of the posts has recently gone to pot.

 

not that the tach is the most accurate, but I would swear that my AP1 VTEC engages at 6200.

 

at WOT, i can definitely feel vtec kick in at 6k rpm, but i read somewhere that vtec depends on throttle position, such that when under say 30% throttle, vtec doesn't engage, or engages later? is that true?

 

We have a forum for passing mis-information. It's called honda-tech.

 

Under WOT, VTEC engages right at 6k, *according to the tack.* Tach is off about 100-200 RPM at 9k, but no more than 100 RPM off at 6k.

Modifry has a free mod on his Web site that provides a VTEC indicator, but at WOT I can't see any need for it, because you can both hear and feel when VTEC engages.

As far as I can tell, and I could be wrong about this, but as far as I can tell, VTEC engagement is purely a function of RPM and oil pressure. I base this on the diagnostics in the factory shop manual. You warm the engine, rev to over 6k, and VTEC is suppose to engage, regardless of throttle position (and with no load). If WOT is reqired for engagement, then the diagnostic procedures in the factory shop manual won't work.

 

Here at 5280ft above sea level my VTEC doesn't engage til about 6.5k. When I drive up to Mt. Evans which is over 14k above sea level, the VTEC doesn't engage until around 7k.

Scott-

 

[QUOTE=S2K-F8,Sep 19 2007, 12:14 AM]Here at 5280ft above sea level my VTEC doesn't engage til about 6.5k.

 

I'm not sure about you guys, but my VTEC kicks in at 4.5K BTW I have an APDeuce.

 

From my old B16A VTEC engagement and my f20c I'm inclined to agree with Red regarding the necessary conditions to engage VTEC despite what I've read and been told on here several times.

I've been told WOT is required.
WOT does NOT seem necessary, provided there is enough oil pressure.

I'm curious to know from someone who has a shop manual as well. **Only from my driving experience** have a I notice that RPM and oil pressure seem to be the only factors.

It seems possible to me that this perceived late engagement of VTEC is as a result of partial throttle resulting in a lack of sufficient oil pressure until somewhere in the mid-upper 6KRPM at which time a) RPM has exceeded the minimum of 6K and b) that oil pressure finally reaches high enough to engage the VTEC.

 

The last time this debate came up, someone (Elistan, I think) mentioned that he has seen late VTEC when driving at high altitudes. Maybe there's input from the MAP sensor or something that is affected by altitude.

As for me, in Dallas @ about 600-800 feet above sea level, my VTEC crossover is at 5850RPMs.