99CIVICFTW

i have a question that i have been wondering for a while now. how is v-tec better than non v-tec? i guess i'm asking cause i don't really understand how it works. i've thought about putting a y8 head on my y7 but is the only gain i would be v-tec? does it have more power? does it rev higher? or is it a bunch of bull? sorry to sound like a noob but i don't care. thanks

Jarrod

Well. I dont know about D-Series but B-Series... it's simple.

The VTEC heads (on b-series) have more advantages from the get go. Goog gasmileage, more research put into them and the abilitiy to put bigger cams into them.

Crower 404s for the LS/b20 head are almost the biggest cam you go with, streetable wise. They are around the same size as a Type R cam. Head swap and Type R cam and you have the same amount of whp. Thru the curve, thats a different story but o well, back to the question at hand.

The VTEC heads are made to turn RPMs better, meaning a better port job, better rocker arms. They also have bigger valves than the non-vtec heads, so they can flow more CFM.

Thats in a nutshell. Just throw a vtec head on there and call it a day.

My buddies y8 head w/ z6 manifold on a y7 bottom end was pretty stout for what it was. Quicker than his stupid LS swap.

Enigma

VTEC allows for a less aggressive cam profile to be used along with a less aggressive fuel map for economy. When a programmed RPM range is achieved the VTEC Solenoid pressurizes oil rails in the head to engage the more aggressive VTEC cam lobes on the intake and exhuast cams. This allows more air and fuel into the cylinders thus creating a larger explosion and more power.

There is a LOT of R&D behind VTEC.. so don't think you can get away with one of those nifty VTEC controllers.. it is only a matter of time before *BOOM*

If you are looking for more HP VTEC is the route to go.

If you are looking for more torque non-VTEC is the route to go.

The only reason I say this is the dyno sheets I've seen in my experience.. and the over-all build. VTEC has generated more HP and non-VTEC has generated more torque.

I'm sure there is a LOT more to it than just VTEC and non-VTEC.. but I'm not a master at thermodynamics, engineering, mechanics, ect. ect.

If I could find the vid on YouTube I'd show you an EG with a turbo LS motor pushing over 400 lbs of torque and 600 hp.

Hope this helps,
Enigma

Chimichangas

accordkid, sorry to get off topic, but i saw you at walmart over here by my house. over by sandbridge. you look really young, dude

Fabrik8

This often has more to do with the stroke of the engine than the heads. Having smaller ports in a non-VTEC head helps with low end torque though (because of higher port velocity), but then you run out of flow at higher flow and RPM. This is why an LS-VTEC setup is a nice comprimise. You have the torque from the longer LS stroke, and higher flowing ports (and better cam profiles) from a VTEC head.

slowciv91

fuck a single cam go with dohc

BAD4DR

You're the closest I've seen to describing it:

It's all about cam profiles. If you tried to run the VTEC enabled lobes, at idle, simply put, the car wouldn't idle well at anything less than...1200 RPM?

The biggest gains from VTEC, (excluding the slightly better port design, and increased valve size, to utilize the better cam profile) are in driveability. It gives you a very mild daily driver cam, and when you step on it, it gives you race car go-fast.

The reason the non-VTEC motors show better "torque" is because they have a traditional cam profile, it doesn't activate, it's always there. So, in effect, it's pushing a much more radical cam profile much sooner. So, it shows much higher torque peaks than a VTEC engine will, when the cam doesn't initialize until ~5K RPM.

Anyways, I hope that sheds some light.

BAD4DR

There's almost no torque increase from the 1.8 mm change in stroke.
And, the torque has a LOT to do with the heads. You said it, increased velocity at lower RPM's.

An exception, is the TypeR head. The ports are much straighter, a function of the head being taller, and the tops of the ports raised. This allows a much straighter path for the airflow. Much like a Hemi head, it causes the low-lift flow (What gives you torque, for those who don't know) to be improved. It also allows for very little restriction, and a much more ideal port shape, that doesn't allow the air to "slow down" as it flows through the port. Curves in a port can hurt the flow tremendously.

So....

Take it for what you will. The smaller valves, and smaller ports allow for better low lift flow on the LS head. You swap to a LS/VTEC setup, and the only thing you really gain is some $$ saved by not having to buy a GSR or TypeR bottom end, and a very small amount of displacement. For a Turbo setup, you also end up with less compression than a straight VTEC motor, which can prove benificial. For N/A, there's no need to build a LS/VTEC. B20/VTEC, maybe....

BAD4DR

And, one other thing you may notice:

Torque peak generally occurs before 4500 RPM. VTEC doesn't activate until after that. The reason VTEC motors produce more "power" is because they maintain more of the torque peak longer. Meaning, that although they don't show the big "peak" numbers, they may very well have a wider actual powerband. That totally depends on application, RPM's turned, gearing, and many other factors.

To the original poster:

If you will PM me specifications, I'll run a DynoSim on it, and give you a comparison.
Helpful information, for a more accurate check:

Bore/Stroke
Actual Compression
Valve Sizes
Full Cam profiles for both heads. IVO/IVC EVO/EVC points included.
Flow-Bench data for the heads in question, including test pressures, with no less than 4 points of reference (valve heights tested.)
Exhaust type used.
Intake type used.


I can send you a dyno graph, plotted points, and spec sheet as tested on the sim.

99CIVICFTW

thanks a ton. i pretty much get it now and i like what i'm hearing so i'm thinking mini me swap. thanks again everyone who helped.

yeah, that was me. i'm almost 17 but look mad young. it's all good though.