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er... ok..

um, okay wait.. your question is a displacement question :P

the more displacement you have, the more gas you can burn during each rev.

you increase displacement by making the cylinders bigger :P um, when you bore a cylinder, you're widening the chamber




I hope that made sense :P it's 7am and I'm.. not awake yet -_-;

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okay yea that made sense. I thot that's what was happening but wasn't sure.

hm....here's a good question for ya. vtech....how does it work and also the new smart vtech system also. heh have fun.

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Shift_

"cuz no matter how long U've known them or how well U think U know them..the friendship can be over in a second" ~Indecisive

"you don't realize how much of a luxury cup holders are until you don't have em" ~Indecisive

ok i think i have the answers

VTEC:
You know about the valves that let air into the engine and let exhaust out of the engine. You also know about the cam shaft that controls the valves. The camshaft uses rotating lobes that push against the valves to open and close them.

It turns out that there is big relationship between the way the lobes are ground on the camshaft and the way the engine performs in different RPM ranges. To understand why this is the case, imagine that we were running an engine extremely slowly - at just 10 or 20 RPMs, so it took the piston seconds to complete a cycle. It would be impossible to actually run a normal engine this slowly, but imagine that we could. We would want to grind the cam shaft so that, just as the piston starts moving downward in the intake stroke, the intake valve would open. The intake valve would close right as the piston bottoms out. Then the exhaust valve would open right as the piston bottoms out at the end of the combustion stroke and would close as the piston completes the exhaust stroke. That would work great for the engine as long as it ran at this very slow speed.

When you increase the RPMs, however, this configuration for the camshaft does not work well. If the engine is running at 4,000 RPM, the valves are opening and closing 2,000 times every minute, or 3 to 4 times every second. When the intake valve opens right at the top of the intake stroke, it turns out that the piston has a lot of trouble getting the air moving into the cylinder in the short time available (a fraction of a second). Therefore, at higher RPMs you want the intake valve to open prior to the intake stroke - actually back in the exhaust stroke - so that by the time the piston starts moving downward in the intake stroke the valve is open and air moves freely into the cylinder during the entire intake stroke. This is something of a simplification, but you get the idea. For maximum engine performance at low engine speeds the valves need to open and close differently than they do at higher engine speeds. If you put in a good low-speed camshaft it hurts the engine's performance at high speeds, and if you put in a good high-speed camshart it hurts the engine's performance at low speeds (and in extreme cases can make it very hard to start the engine!).

VTEC (which stands for Variable Valve Timing and Lift Electronic Control) is an electronic and mechanical system in some Honda engines that allows the engine to effectively have multiple camshafts. As the engine moves into different RPM ranges, the engine's computer can activate alternate lobes on the camshaft and change the cam's timing. In this way the engine gets the best features of low-speed and high-speed camshafts in the same engine.

VVT-I:
The latest Toyota system, VVTl-i, ends up working in much the same fashion as the Honda V-Tec in that it uses a mechanical device to swap over between a 'small' cam for low & medium revs and a 'big' cam for high revs.

.btw.

that was me, sangxjin

so is that called a twin cam shaft? dont' a lot of non Honda cars have twin cam shafts? or are they different things?

and what about Smart VTEC? The new Acura RSX's are said to have Smart VTEC. what's that about?

hehe sorry bout all the questions. but I"ve always been lacking on the technical side of cars.

and that explaination was good. at first I didn't get it but as I read on it made sense. thanks.

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Shift_

"cuz no matter how long U've known them or how well U think U know them..the friendship can be over in a second" ~Indecisive

"you don't realize how much of a luxury cup holders are until you don't have em" ~Indecisive

i got a chance to drive Rhys Millen's Mitsubish Evo 6.5 when they were over here in WA for the SCAA Rally Championships up in the logging roads of Shelton, WA...(i got to drive it cuz my youth pastor is friends of both the Millens and he knows people on factory team at Mitsubishi) the thing is a freakin' beast, too bad Rhys didn't even make it past Stage 1 tho, and I got pelted by rocks as Team Hyundai came by on the part of Stage 1 I was watching from hehe

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and i thought the cop was a prostitute...

quote:

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Originally posted by indecisive
so is that called a twin cam shaft? dont' a lot of non Honda cars have twin cam shafts? or are they different things?

and what about Smart VTEC? The new Acura RSX's are said to have Smart VTEC. what's that about?

hehe sorry bout all the questions. but I"ve always been lacking on the technical side of cars.

and that explaination was good. at first I didn't get it but as I read on it made sense. thanks.

---

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Props To Huby

heh aights. thanks

meh. I don't really care who answers. U've been a real big help to me. thanks.

EDIT: oh yea, and what about the different boosts wif Turbos? like 4 stage boost and whatever. is that how much compressed air is shot into the chamber? the higher the boost the more air? or what?

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Shift_

"cuz no matter how long U've known them or how well U think U know them..the friendship can be over in a second" ~Indecisive

"you don't realize how much of a luxury cup holders are until you don't have em" ~Indecisive

smart vtech...
you mean
i-vtech...and note, the rsx goes clockwise instead of the counter-clockwise versions of the older honda models and makes.

quote:

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Originally posted by indecisive
heh aights. thanks

meh. I don't really care who answers. U've been a real big help to me. thanks.

EDIT: oh yea, and what about the different boosts wif Turbos? like 4 stage boost and whatever. is that how much compressed air is shot into the chamber? the higher the boost the more air? or what?

---

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aight thanks. who's tim? is it sangxjin? or who?

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Shift_

"cuz no matter how long U've known them or how well U think U know them..the friendship can be over in a second" ~Indecisive

"you don't realize how much of a luxury cup holders are until you don't have em" ~Indecisive

No, my friend tim is a white guy who spent the last like 3 months researching turbo's :P

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ahha oh I see lols


well, if anybody can help me I'll be happy heh

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Shift_

"cuz no matter how long U've known them or how well U think U know them..the friendship can be over in a second" ~Indecisive

"you don't realize how much of a luxury cup holders are until you don't have em" ~Indecisive

uhh.. well here in america, they measure boost in lbs of pressure... or PSI..


I think in japan they measure by bars or something -_-; I dunno..

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yea ur rite prototype..

PSI here
BARS in japan

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Props To Huby

more psi = more air into mixture then rite?

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Shift_

"cuz no matter how long U've known them or how well U think U know them..the friendship can be over in a second" ~Indecisive

"you don't realize how much of a luxury cup holders are until you don't have em" ~Indecisive

er... psi means pounds per square inch?

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yea like in a tire..

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Props To Huby