ghettoturbo

he is asking why a vtec head is better than a non-vtec head with big cams which would theoretically accomplish the same ----. While ill admit ive never done any hardcore research, i believe the vtec heads themselves flow significantly more than the non-tec heads. So by using a vtec head you are starting with a better platform.

Jorsher

You get a broader powerband with two sets of cam profiles. A non-vtec with big cams doesn't accomplish the same. Each cam profile is going to have its "sweet spot" where the valves aren't opened too long or too briefly. Sure, non-vtec and a fat cam you'll have better top-end performance which is most likely where you'll be doing your "performing" at anyway, but bottom end won't be as good as a vtec head. Top-end will be just as good on a non-vtec (depending on cams), but lower end will suffer.

78NOVA

honestly i dont understand why there is even any fuss by this. i drove two different vtec equipped civics, both d16z6 and couldnt even tell there was vtec. honestly to myself i probably wont even touch it. if i do, i do, but as it sits now i havent even had the slightest urge to go vtec in my hatch. i think honda did it right the first time when they had the d16a6 in the US si civic/crx.

ghettoturbo

i dont think he (kain) was asking about the powerband down low, and my post wasnt in reference to that either, sorry i left that out. I think a non-tec head (b-series at least) with cams will take a decent amount of work to equal the flow of a vtec head (especially with cams), but i dont know so dont listen to me lol

kain

ah ok. i understand. i just dont understand why they think they are getting that much more power. i understand about low end drive ability, but i think most people dont give a ----. i know i for one dont give a ----.

my first 2nd gen had something similar and everyone swore that taking the system out wasnt a good idea and blah blah blah hurt low end driveability blah blah blah. taking it out and disabling it improved my overall driveability, and i gained some hp too. but then again,, in the rx7 you have ---- blocking the air stream.

if the geometry of the head is different, then i understand. but if its the same, then i would be the guy to just throw in some cams and give it a nice tune.

Jorsher

Basically, as a cam spins faster, the valves are open for shorter amounts of time, and its harder to move air out/in. You don't want them opened too long or it'll hurt performance. With vtec, instead of having one point where the cams are very efficient, you'll have two, and it stretches the powerband out a bit. Non-vtec is tuned for "decent" performance all around, so it's range of efficiency is probably close to the midway mark of the rpm range. VTEC it'll be tuned closer to having efficiency at both the bottom and the upper end, so vtec engines usually end up with more power because they can open the higher end up without sacrificing low-rpm driveability.

I don't really see how vtec would be much different than a non-vtec with fat lobes, since you're going to be revving high anyway which is where the cams will be tuned for efficiency. For the widest powerband, vtec is better to have though.

If they ever come out with a continuously variable valve timing, that would be optimal, and a bitch to tune.

buk9tp

well from what i heard you cant feel the difference in sohc's but dyno will show the difference..

i definatly felt the difference in my rex.. and im sure dyno would show a difference too?

78NOVA

i couldnt tell ya either, ive never driven a b series before. but i have driven and h series and i love the vtec when it kicks in on it.

buk9tp

buy my crx and swap the b16 into the 7

Guy-Fast

Well ported ls b18b1 heads dont even flow what a stock b16a/b18c1 head does. This becomes an issue when you start to want to make large power#'s


The ls valvetrain/rocker assembly also doesnt except that large of cams and has major issues with high rpm's


You have never even taken either apart so your talking again out of your virgin ***. Vtec heads the dohc form are so popular for a reason out of the box they had bad ****'s. The rocker assembly is bulletproof and can handle whatever you throw at it.


Conclusion ls heads are cool and nothing wrong with them but the vtec head is the hot blonde in the class the ls head is the kinda chubbby cute girl.