Why dont all cars have vtec? (or equilvilent)

Eliot

Eliot

Eliot

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Joined
29 Mar 2005
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i was wondering this the other day, i mean i really want a dc2 right and i was thinking if vtec makes a car that quick from a 1.8 engine then why dont all performance cars have something similar, also as vtec is mainly a economy thing why doesnt every small hatchback have it geared for economy. or am i being monumentally retarded
 
They aren't the same though, altering the cam phasing is a bit different to completely swapping profile on the fly.

Essentially though, there isn't any point. Crappy econo boxes are already cammed for low rev running, asthmatic at high revs but nobody cares. Most do have cam phasing VVT now though.

I do believe BMW have the most advanced application now though with Valvetronic, variable lift, duration, and phasing.
 
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Basically it's deemed too expensive for a basic model. I'm sure the added expense would soon pay for itself in increased economy if, like you said, it was set up specifically for economy.

However, as with most things, the Energy Efficiency Paradox jumps in the way and it's used to make things go faster instead of making things more efficient.
 
peterattheboro said:
Does an investment banker want a screaming Vtec or a smooth low revving V8?
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what does that have to do with this thread? It seems you don't understand what vtec is all about.

Let me spell it out. It isn't to allow a high rev, high output motor. Anyone can do that by sticking wild cams in. VTEC allows that but without the disadvantage of awful low rpm running, it allows for a wider torque band, and that's something than anyone can appreciate.
 
peterattheboro said:
Does an investment banker want a screaming Vtec or a smooth low revving V8?
Click to expand...

You do realise the whole point of VTEC don't you?

Different cam profiles give engines different characteristics. An agressive cam will give higher peak power but will give useble power over a narrower range of revs. A softer cam profile will give lower overall power but is drivable over a wider range of speeds.

Without VTEC you've got to pick one cam profile and stick with it, for this reason you usually have to pick some kind of compromise between peak power and drivability. With VTEC you can effectively have the soft lazy cam AND the mental race cam in the same engine and use whichever is appropriate depending on circumstance. There is no downside other than slightly increased complexity and hence cost.
 
ajstan said:
Is there a jerk when it kicks in then?
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There's a noticeable change, it's certainly not a smooth changeover on the standard map.

Good thread on it here:

http://www.team-integra.net/forum/display_topic_threads.asp?ForumID=10&TopicID=131578

the experienced guys don't want to see that hard distinct transition. Why?

it creates kick wheelspin issues at the front wheels and you lose traction and is hard on the motor with an abrupt transition like that...if you did it right, you should hardly notice the transition at all...the power should come on smoothly and transition up smoothly as you pull harder up the tq curve. secondly, the Torque should be optimised around that 5800-6400 rpm area to be as high as possible because your rpms drop to that level after a redline upshift at full throttle. You upshift at redline and boom! the rpms drop down but they drop right into a strong torque level whereas the abrupt step VTEC switchover car has the rpms drop into a low torque and then suddenly pop up.
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