I didn't know exactly where to post this, but I'm asking on a FI'd Honda engine, we'll say the B18C1 for argument's sake, is VTEC pointless if you aren't going to DD it? Oh, and why?

 

I wouldn't call it pointless, but definitely LESS necessary. The main function of VTEC is to have 2 cam profiles, low for most of your driving, and hi for when you are beating it's ***. If your car is a trailer queen, then you can run all the cam you want all the time without having to worry about drive-ability, not to mention, it should in theory be more reliable because of the less moving parts involved.

 

I would definitely agree with that. I guess I should have been a little more specific, but that's a good answer for part of it. Track only cars, I totally agree with that. Now, what about weekend cars, or cars that you take out just to have fun? Anything that is not a DD.

 

vtec is pointless on a DD car. you want Vtec for when your racing. drag racing. beating it and having fun. vtec makes Power. this question is one of the weirdest questions I've ever heard. why wouldnt you want vtec.???

 

that now depends on power goal and setup...

 

You are incorrect in many ways. First, VTEC was designed for daily driving cars. DD's need VTEC in order to switch from a low cam profile (that delivers maximum low-mid range power and fuel economy) to the high cam profile that maximizes power and disregards economy. VTEC is so great because of this. It allows you to have a powerful 240 hp F20C 2 liter engine, but be able to drive it regularly around town at low rpms. Without the low cam profile in that engine it would not be very streetable.

A race car does not need VTEC. This is why the Toda VTEC killer cams were developed. These cams do like the name suggests, they cut out VTEC. However, you cannot use them in a daily driver because there is no power in the low range. A race car only needs the high cam profile because it delivers maximum power.

Think of like each VTEC engine has 2 sets of cams. One that allows for maximum power in the low-mid range, and one for maximum high range power. Vtec is something that switches between these cams for a better OVERALL power curve. Having only the low cams will result in poor high end power, and having only high cams will result in poor low end but great high end. Race cars only need the high end, and DD's need BOTH.

I feel like most people think of VTEC like nitrous which is false. VTEC isnt what makes the power. The higher cam profile that is switches to makes the power. A car without vtec, but with the same high level cam profile, will make the same high end power. But because it doesnt have VTEC to switch to the lower cam profile, the motor will suffer in the lower RPM range. This is why VTEC is important for DD's to get the best of both worlds.

Enough said.

 

theoretically you COULD make an LS head flow as much as a vtec head, with gigantic cams, and no daily drivability,

kinda like those domestics that have a hard time idling

 

lol you totally didnt get what i even meant. I didnt need you to right a book telling me what vtec is. i already knew everything you said. !!

 

First let's look at it from a b-series perspective: You want a VTEC head if you want to rev above 7k consistently & reliably.

A non-vtec head will always be stuck with rocker arms that pivot on a ball stud One common problem for auto-x guys with LS heads is lifters that fly off when that ball stud breaks or the nut backs off. I know someone who averaged 1 replacement per track day. Both can be modded to have big ports, huge lift, light cam (vtec killers), etc, if you just want peak numbers. However, a missing lifter will not benifit you.

DOHC VTEC heads have 2 hollow tubes that the rocker arms pivot on. The only issues with those heads is the LMA's. Luckly the new spring version fixes the binding issue that can happen with huge cams (or age). They also have a much better oiling system that's integrated with the "cam holders". Having cam girdles are great bonus just by themselves.



For a generic race engine, ESPECIALLY with a turbo, it's a big help. Find me a DSM owner that has bigger cams AND has better spool/response vs the stock cams. One thing to note is that most SOHC users of the most popular Comp cam (59300) actually see a faster spool because of how the primary lobes are designed for mid-range. Stick a comprable cam in a non-vtec sohc head, say a delta regrind, and it won't spool any sooner.

For a race car program with a huge budget, you wouldn't want the extra complexity. Instead you can just test dozens of cam profiles, dozens of port designs, dozens of manifold designs, etc. Then you can set the ideal gearing for your transmission since your team has access to *any* gear ratios required. Most pro teams won't use drivetrain parts for more than a few hours of actual use.

 

its gonna have a lopy idle once u used those vtec killer cams. and run only vtec rocker arms

 

This isn't a vtec head vs. non-vtec head question. It's asking if vtec is pointless on a non-DD car. It's not that cut and dry. Like mentioned vtec is great for a DD as it allows for the high end power with resonable to good mpg. This isn't hard to understand, yet your trying to be Billy Badass and in the process making an *** out of yourself. Your pure ignorance is amusing.

He hit the nail on the head. Don't be pissed you have no idea what your talkign about.

 

so can you lock the rockers and only use the vtec lobe on say some pro 1s?

 

Ok, so I understand what VTEC is and what it's purpose is. I should have clarified that to begin with. I guess it would have better been said like, "If someone were to say that VTEC is useless on non DD Hondas, what would you say?" I mean I understand that there are a lot of variables here, but if I were to have a B18C1 and wanted to turbo it and drive it around sometimes like weekends, meets, and drag days, would VTEC be useless in that situation or similar ones.

 

i suppose it wouldn't be.

 

if you plan on driving it around at all on the street, i would not switch over to vtec killers.

 

What else could you mean by what you said here?


If your car is going to do any kind of "regular" driving, which includes driving anywhere under 5k rpm, you are going to need VTEC in order to keep the top end power. Pure drag racing cars and road racing cars dont need VTEC because they have no need to use the powerband under 4-5k rpm, so they have crazy cams that only make power up high.

 

I would agree that the traditional VTEC implementation isn't terribly useful in a purpose built drag car, road race car, etc. where the engine speeds can be kept in a specific range, and a custom camshaft designed to deliver maximum power in that (probably fairly narrow) range. The VTEC mechanism just adds additional complexity and points of failure to the drivetrain that you just don't need when racing.

That being said, i-VTEC with phasing of the intake cam has tangible racing benefits in just about every application.

 

And it'll be a gas killer with no low-end power.

Low-end is what you need for traffic.

 

miller, t1, all the fast guys dont use "vtec".

 

im not quite sure i nor anyone else understand you here brotha...

basically vtec head is great, but for a car that can idle at 1500-2000 rpm and not worry about it (non dd) then non vtec style cams (vtec killa) are great for race cars