té_qui wrote:
> Need people's expertise here. I have a 92 VX with the VTEC-E. I'm having
> problems with something I have yet to discover. My question is ... In my
> quest for the search of my problem, is there a way to manually activate the
> VTEC to always be on. Right now, The VTEC-E is set to activate at about
> 2500-3000RPM. My problem is that below these RPM, I get very low performance
> but as soon as I hit 3000RPM, the VTEC or whatever kicks in very hard to
> scream down the road. So I'm basically tring to see if it's the VTEC not
> properly engaging itself or if it is something else. If I unplug the VTEC
> spool valve or the pressure swith, don't remember which, I pretty much solve
> my problem but have no VTEC above 3000RPM.
> Any Ideas on how to activate VTEC? Do I need to ground the Spool valve or
> the pressure switch?
> Thanks
> Frank
>
>
3k is /way/ too low for the vtec cam. fixed cams are a compromise based
on extensive research to map an engine's volumetric efficiency. having
two sets of cams [vtec] allows a broader effective power band [two bands
with an area of overlap between them]. the lower cam set works well up
to 5k and is relatively torquey. the vtec is much more powerful /at
high revs/ but lacks low end and is narrower. on real high tune
engines, the power band can be as little as 1k rpm. trying to stick
with the majority of rpms on the vtec cam achieves nothing but emissions
problems and premature wear of the cam. notice how there's two sets of
lobes for the low rev cam profile and only one for the vtec? that means
greater load bearing area and therefore lower wear rate for the region
in which a road engine spends the majority of its life.

bottom line - if this car's a daily driver, don't monkey with the vtec.
anything below 4k is absolutely pointless. if you want this car for
the track, don't bother with the vtec at all - you shouldn't be pulling
at much less than 6k anywhere on the circuit so you may as well just go
straight to a single profile cam with a high rev power band.