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Discussion Starter · #1 ·
100% noob here. I know VTEC involves electronically regulating the valve timing to keep the revs up in between shifts (at least thats what i thought).

How does it work and whats the big power increase from?

I sincerely apologize for not knowing all about VTEC. I throw myself at the mercy of the High Church of Honda.
 

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vtec stands for variable valve timing and lift electronic control


basically what it does is give you 2 sets of cams
one for low rpm and one for high


ever see and old muscle car idleing and sound like its about to stall?
tahs becasue its using a cam for higher end power and struggles to stay alive in low rpm...vtec eliminates this problem buy sliding the cam down to a dif set of cam lobes at the set rpm/throttle angle


the idea is taht at higher rpm you want your vlaves to begin opening and closing earlier(so that they are fully open for the majority of the stroke)....this is not nessasary and will actually hurt performance at a lower rpm (which is why it still boggles my mind when people buy a vtec controller and set it to engage at a lower rpm....kinda defeats the purpose)


hope that helped you understand a lil


and btw the dif between the vtec model sol and teh si is about 30 hp....and a dif of about 60 from the s model BUT THE VTEC MODEL IS ALSO DOHC so you cant really compare them....the si is a single stage vtec (jsut the intake side)
 

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VTEC is a system that allows the engine to switch between different sets of cam lobes. One set is good for lower RPM running giving good fuel economy and a smooth idle, the other set has more agressive timing for good high RPM breathing for max HP. Someone had a great chart that showed all the different variations of VTEC.
 

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Discussion Starter · #5 ·
So, basically, if you have a VTEC equipped car, and drive it pansy-footed, it's about the same as a regular engine until you engage the high-power cams by flooring it? And kudos for the turbo rig, soul93
 

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you get the best of both worlds. when normal driving you get the good gas mileage. but when in high rpms, these engines really shine aside from the others. the engines youll feel the vtec crack the best are the h22's the b16's and the b18c5's. there are also different types of vtec. the DOHC VTEC is the best, then you got the VTEC-E for economy, the 3 stage vtec (or is it 2?) i dunno, there is a thread about it somewhere on here i believe. pretty cool shit. then other companies tried to copy hondas theory like toyota with their vvti system...cant even feel that shit (but its there) what good is that.
 

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Discussion Starter · #8 ·
One reason I decided on a non-VTEC car was that I had seen that VTECs get less mileage than a regular car. I guess that's just because when the extra power is there, it's gonna get used. Long live 4th gear and 2-lane country roads!
 

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soul 93 said:
vtec stands for variable valve timing and lift electronic control


basically what it does is give you 2 sets of cams
one for low rpm and one for high


)

not really. vtec is the 3rd (enlarged) camshaft lobe that is activated under certain throttle conditions. the lobe is usually not in use until the conditions occur, when the vtec lobe activates, which has longer duration of the intake valve opening, causing overlap-where the intake and exhaust valves are open at the same time.

its kinda like when youre masturbatin and youre goin, goin, then youre gettin close to orgasm and vtec kicks in for more power and orgasm

but non-vtec motors are better for boost because valve overlap/high manifold pressure dont mix. i think the boost actually has a chance to leak out before the exhaust valves close since theyre both open when vtec activates. but it isnt something a little cam tuning couldnt solve.
 

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johnlude85 said:
you get the best of both worlds. when normal driving you get the good gas mileage. but when in high rpms, these engines really shine aside from the others. the engines youll feel the vtec crack the best are the h22's the b16's and the b18c5's. there are also different types of vtec. the DOHC VTEC is the best, then you got the VTEC-E for economy, the 3 stage vtec (or is it 2?) i dunno, there is a thread about it somewhere on here i believe. pretty cool shit. then other companies tried to copy hondas theory like toyota with their vvti system...cant even feel that shit (but its there) what good is that.
Toyota probably tuned the system so it would engage smoothly so you wouldn't feel it. True many companys have come out with their own versions of variable timing and/or lift for their engines but I wouldn't say they were coping off of Honda. Vtec gives greater lift and duration and more overlap but I believe that the 'Yota system also varies the timing. On the Ford Mustang V8 they vary the timing of the cams but don't have extra lobes for more lift. Hell BMW has a system that varies lift to the point that it is used to throttle the engine. We may someday see the elimination of camshafts and have valves operated by solnoids. Yes I know a bunch of crap about engines.
 

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ksniperfox said:
not really. vtec is the 3rd (enlarged) camshaft lobe that is activated under certain throttle conditions. the lobe is usually not in use until the conditions occur, when the vtec lobe activates, which has longer duration of the intake valve opening, causing overlap-where the intake and exhaust valves are open at the same time.
waht is a cam but a rod with lobes on it????........vtec cams have 2 sets of lobes so in essence 2 dif cams.....and the dif lobe sizes is what opens the vlaves earlier and causes overlap when the other set of lobes is in use (vtec lobes)........perhaps im reading your post wrong but what i said is a simpler to understand version of what you said

the third lobe your talking about (i think) is becasue our motors only have a single stage vtec (for intake valves only)...so there is only 2 sets of lobes for the intake side, and exhaust valve timing remain unchanged
 

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soul 93 said:
waht is a cam but a rod with lobes on it????........vtec cams have 2 sets of lobes so in essence 2 dif cams.....and the dif lobe sizes is what opens the vlaves earlier and causes overlap when the other set of lobes is in use (vtec lobes)........perhaps im reading your post wrong but what i said is a simpler to understand version of what you said

the third lobe your talking about (i think) is becasue our motors only have a single stage vtec (for intake valves only)...so there is only 2 sets of lobes for the intake side, and exhaust valve timing remain unchanged
my mistake, the way i interpreted it was that you meant all vtec motors are DOHC. but you just explained what u meant. my bad. :hug
 
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