ORIGINAL: DA KID RYU

Yea Yes my bad bout about my cap lock....
its a bad habit....
yea Yes i I understand what all u you guys are trying to feed me and all..
i I gotwat what JOHNL told me i I understand dat that two cams two different opening times.
onesOne's for economicsideit runs in da the low end mid rpms.
da The other is wen when u you over do ur your rpmsi.e wen when racing or testing ur your engine...

You get the drift I'm sure.

all im saying da second cam da one dat kicks in is da one dat is giving it da extra 15 hp...

sorry just a persistent person...
all um saying is i know how vtec works i know how it kicks in i knowdat is a xtra rocker dat kicks in wenda rpms fuelare high..
but isit da cam dat lets it have 15hp extra...thanks....

ORIGINAL: YeuEmMaiMai
vtec may give you an extra 5-7 HP......the reason the engines have more power is they also got better flowing intake and exhaust

ORIGINAL: JohnL

Talking about bad habits, sorry, but I find your posts very hard to read because of your spelling and failure to use capitals etc. I'm not trying to be nasty, and Iunderstand that you're probably using an informal type of shorthand that's becoming more common in internet discussions and texting etc, and you're far from being on your own (unfortunately!), but it makes reading it hard work, as does incorrect use of the cap lock function.

I've corrected some of your post below by adding / inserting correct English in bold after your errors. Syntax and grammar could also be better, but I suspect English may not be your first language so I'm not complaining about that, one step at a time!

Yes, it's basically the cam that does it, though it's not quite that simple beause the ECU will deliver a different quantity of fuel and probably alter the ignition timing to suit the characteristics of the vtec cam profile.

ORIGINAL: JohnL

It seems to me an awful lot of expense and engineering genius for Honda to be wasting on a mere 5 to 7hp gain. Why go to all that trouble for such a tiny increase? I don't buy this, sorry.

If we look at this from the other end, lets say Honda makes an engine that is basically designed for good top end power with good flow characteristics into and out of the engine, and uses a relatively adventurous cam profile to enhance this. They now have an engine that's at home on the race track but not very tractable on the road, so, they invent 'vtec' so that they can also use a cam profile in the same engine that enhances bottom end / mid range torque and power. So, in this case the purpose of vtec isn't really to increase top end power, but rather to increase bottom end and mid range to a level that is acceptable for a road car(?).

ORIGINAL: DA KID RYU
Yes, it has become a real bad habit from texting to just shorthand writting. You have a gift or something.lol. my first language is spanish and I do speak it more often then english....
And thanks JOHNLyour not been nasty your right tho about my english..

ORIGINAL: DA KID RYU
Yes, there it is the answer that i was looking for.The ecu and different cam profile quantity of fuel and inginition timing is what'sgiving it the extra hp.

ORIGINAL: JohnL

That is so much better, keep up the good work! I know a lot of younger people who speak 'text' as their first language would probably have no trouble understanding your 'textese', but I think you'll find that in general you'll get more responses to your questions if we less linguistically fashionable types (old farts maybe!) don't have to actually decipher what you're saying!

It's all about breathing, i.e. how much air the engine can 'inhale' in a given amount of time at whatever rpm. Ignition timing and fuel injection changes are just detail adjustments to suit the breathing characteristic at play at any given moment, necessary but not the main game.

ORIGINAL: JohnL

It seems to me an awful lot of expense and engineering genius for Honda to be wasting on a mere 5 to 7hp gain. Why go to all that trouble for such a tiny increase? I don't buy this, sorry.

If we look at this from the other end, lets say Honda makes an engine that is basically designed for good top end power with good flow characteristics into and out of the engine, and uses a relatively adventurous cam profile to enhance this. They now have an engine that's at home on the race track but not very tractable on the road, so, they invent 'vtec' so that they can also use a cam profile in the same engine that enhances bottom end / mid range torque and power. So, in this case the purpose of vtec isn't really to increase top end power, but rather to increase bottom end and mid range to a level that is acceptable for a road car(?).

ORIGINAL: JohnL

Thinking about this a bit more, Honda makes two basic kinds of vtec engines; a) top end screamers with acceptable mid and lower range (more or less what I was describing above, i.e. 'high performance' engines), and b) more mundane lower performance engines with good bottom end/ mid range torquebut still with a better top end than an otherwise similar engine without vtec.

Engines in the 'a' category can have an exceptional HP per litre output at very high rpm without being complete dogs lower down, certainly more than your suggested 5 to 7 HP gain from vtec. Engines in the 'b' category are more oriented toward achieving better fuel economy from a smaller capacity without sacrifing performance excessively, and may well only see a 5 to 7HP top end gain from vtec...