[rhdef7]

it's probrobly been answered befor but here I go, currently I have a dohc zc motor with cbr 954 itbs and the thing pulls. My bro just got a ef (like mine) and wants a d16 the the motor we pulled out had 270,000 miles on it. he isn't a wrench turner, he just wants me to swap in an si motor and convert over to multiport.


Now my question, is vtec worth having or should I keep my current set up?? I have plans to build what ever motor n/a, high comp, cam/cams head ported with ceeping my itb's, tuning, ect. I have always had dual cam motors I have never had a single slammer. I have had a ls/vtec in my other ef hatch, but that is different from a single. I just want to get some different opinions on guys with and without vtec so I can make a decsion. thanks for your input!!!

 

[Hatch Man (z6)]

I would never go without vtec for the simple fact that it is a honda trademark... I like it too much.

Unless you are planning on major headwork and a custom cam, go with a vtec motor because the vtec head will outflow the non vtec easily assuming neither head is ported, and there is still plenty of room for improvement...

 

[rhdef7]

well either head will be ported with at least a stage 3 cam/cams valve job ect

 

[Hatch Man (z6)]

Heres the thing...

A vtec and non-vtec head have the same potential for flow assuming they have the same lift cam, the same diameter valves, and all the ports have the same total area. You can only port a head so much, and both a vtec and non vtec head are limited in this area.

HOWEVER, a non-vtec head has more potential to make a wider powerband than a vtec head because you will have the same lift regardless of rpm, whereas a vtec head will only flow to it's peak efficiency after vtec is engaged.

For example, a vtec head will have a steeper power curve, and a non-vtec head will have a much broader curve but both have the potential for the same PEAK power level.


The one thing I like about the vtec head is that different cam's are readily available and with a non-vtec head you will need a custom cam to get the kind of power you are looking for.

 

[rhdef7]

so with you set up does vtec engage like a b series vtec motor or is it a more smother change over with more topend?

 

[MrHalder]

read up at nonvtec.com

 

[Hatch Man (z6)]

I use vtec to help build boost, my vtec engagement is at 3000 rpm. I am using a stage 2 cam and when vtec is engaging so low the difference is just like a stock single cam would engage at 5000...

If I engage vtec at 5000 or later I am already at about 15-17psi and it is very loud and very violent... There is no point in setting it that high because it breaks traction. That large power surge at the crossover, although very cool to experience isnt worth a slower time or more turbo lag...