hi all, does anyone know what rpm vtec actually engages on our engines?

~2000-3500RPM depending on throttle position, oil level and pressure, etc.

I believe it is around 4500 rpm assuming the criteria for oil level, oil pressure, etc that BB mentioned have been met. Remember, this is me trying to recall the test for the VTEC solenoid switch.

I can definitely feel a jump in my car in the 2000-3000 range...again at ~4400. I believe one of these is the cam lobe and the other one is a fuel map switchover. A lot of info on the net says the lobe switchover is at 4400 but my own personal experience seems to contradict that. When I have low oil level (VTEC is related to oil after all), the power jump at 2000 is not there. It just feels very flat even all the way to 3500. Also, there was a TSB or news article saying that there was hesitation at low speed, and that was due to VTEC and another solenoid not communicating properly.

In my old GS-R you could hear VTEC engagement as a rather loud click at around 2500-4000rpm depending on various conditions. It would not create a large power increase. The second (and bigger) power rush was coming because of exhaust manifold switching to a shorter path at higher rpms. Is that similar ito Accords?

i think you have it switched around. the VTEC crossover doesnt "click". inake manifold (not exhaust) runners switching, however, could.

the Accord I4's have economy VTEC, which crosses over around the 2000-3000rpm range like Ben said. (actually, it's just switching from 3-valve to 4 valve mode)

the V6's with VTEC have crossovers at ~4500 RPM.

I tend to feel a sudden minor jump at around ~4000 rpm.

I have to give it to the Accord....it's VTEC V6 sounds great past 3000 rpm...

There is no set RPM anymore.... it reads the car for whats needed.

but even though theres no exact RPM engagement point, there's still a VTEC "window"...it's not just going to switch cams willy nilly at any RPM.

The new ones don't have an RPM window.... I'll see if I can find the papers....

Princess, wouldn't that just be for i-Vtec engines with VTC? I've always had a feeling that there was a "window" on my J30 (which just uses the "standard" Vtec system)...but then I could be (and I actually do hope I am) wrong... :dunno:

the description for the previous 4 cyl:

And the description for the new 4 cyl:

new V6 Vtec:

To the original question: here's the info on a '95

That actually makes sense as I thought I felt a crossover around 4700-5000rpm (and the PDF has it at 4900rpm so I was close...lol). I also notice a change in engine note around the 3000rpm mark...I think I remember reading somewhere that there is some sort of intake crossover point atleast in the 6MTs...

i still read the graph as the K24's having a set engagement point for VTEC. the graph in the document you posted shows the big arrows on top saying <--low speed cam--><--high speed cam-->, so i take it that the engagement point is where the two arrows meet (though it doesnt specify RPM).

VTC, however, is always changing the cam phase according to engine load and RPM.