V-tec

[blackbeauty240]

this may seem like a stupid question but what does V-tec stand for?

[240Kuminachu]

very trashy, extra crap

[jmillheiser]

VTEC = Variable Timing and Engine Controli-VTEC = VTEC but only on the intake cam on a DOHC engineVVT-i = Variable Valve Timing w/ intelligence (toyota's version adds the F to a toyota engine code)VVTL-i = Variable Valve Timing w/ Lift and intelligence (the version on the celica and matrix adds the G to a toyota engine code)VTC = Variable Timing Control (nissan's version - there is a hotter version of it that adds the V to an engine code but is not used in the US to my knowledge)

all these systems pretty much do the same thing. they use a self adjusting cam gear to adjust cam timing and phasing on DOHC engines. the performance oriented versions also have special cams with 2 sets of lobes, one set for crusing, one set (which kicks in at a preset RPM) with higher lift and longer duration to increase power above a preset RPM level (usually 6K), the switchover is usually done by an oil pressure powered valve & actuator. This is what causes the "VTEC kick" on performance oriented honda engines

[89sxRCR]

Quote »this may seem like a stupid question [/quote] correct. Proceed to your nearest honda dealer.

[driftaholic]

i thought i-VTEC was intelligent-VTEC and its called that because it continuously adjusts camshaft phase. no?

[Perfectd3]

IVTEC - is the same as VTEC, but it adds VTC (yes, just like a Nissan) and the VTEC system is now a 3 stage, instead of the old two stage system.

[AznRide]

Not only DOHC engines have the Variable Valve Timing system thing, SOHC engines also have them, hence my old civic EX...it was loud, but damn I can't feel my Vtec, lol. After my DOHC swap...whaaam.

[kbrunjes]

VTEC = Variable Timing and Engine Controli-VTEC = VTEC but only on the intake cam on a DOHC engine

VTEC = Variable Timing and Electronic Lift Control (low RPM, small cam lobe, & high RPM, larger cam lobe)i-VTEC = intelligent Variable...

both SOHC & DOHC motors had VTEC and I don't think that there was any self adjusting cam gears

I know this was a petty post, but I am a Honda guy at heart. at least you didn't spell it VTECH that is a common mistake that ricers make

[AznRide]

Well, however kb, there is an aftermarket cam gears for SOHC Vtec engines. You don't need one for intake and one for exhaust, they share the same cam.

How about this question...don't search, from the top of your head, tell me, how does Vtec work. First one answers this wins a...cookie?

[Tino]

I read all about this and knew it like a good porno. All this damn school crap filled my head with garbage and I can't recall the important stuff...

[Nismo1182]

Not only DOHC engines have the Variable Valve Timing system thing, SOHC engines also have them, hence my old civic EX...it was loud, but damn I can't feel my Vtec, lol. After my DOHC swap...whaaam.

Yea sohc vtec motors only have the extra lobe on the intake side and its not that much lift either so thats why you dont feel much when it switches over.

[APEXi240]

I liked the sound/feeling of my pathetic 85zxt turbo hitting boost WAY more than the GS-R hitting Vtec

[PabloHoney]

Well, however kb, there is an aftermarket cam gears for SOHC Vtec engines. You don't need one for intake and one for exhaust, they share the same cam.

How about this question...don't search, from the top of your head, tell me, how does Vtec work. First one answers this wins a...cookie?

I believe he was referring to having "self adjusting cam gears". He was stating that the cam gears did not adjust themselves, different process.

VTEC uses two sets of valve rockers (three actual valve rockers, but the two on the outside are connected, so I call that one set) as well as two sets of lobes. The VTEC lobe is in between the two normal lobes. The valve rocker above the VTEC lobe flaps around freely whilest not in VTEC, and the other two valve rockers are in contact with the normal lobes. When VTEC kicks in, a little pin slides into the third valve rocker (hydraulic actuation, as stated before), and locks all three together. So now the two normal lobes aren't being used, only the VTEC lobe is acting on the valve rocker. Very simple explanation.

Oh yea, and get this, the VTEC lobes have a similar lift and duration to that of a full race cam. VTEC is good sh*t for NA purposes, just not so good with turbos =)

[PabloHoney]

I liked the sound/feeling of my pathetic 85zxt turbo hitting boost WAY more than the GS-R hitting Vtec

So VERY very true =)

[EZcheese15]

Well, Jmil got most of it right....but a few mistakes.

First of all, I-VTEC is intelligent variable timing and lift engine control, like somebody said....

But VTC is *NOT* the same as VTEC. VTC is variable timing control, which does not adjust the lift at all. It just adjusts the timing of the intake cam. Like I-VTEC but without the lift.

Nissan's version of variable lift is called VVL for variable valve lift. This works very similar to VTEC or VVT-Li. It also changes the "D" to a "V" in nissan engine codes. VTC does not.

For instance, the Nissan S14 and S15 SR20DET has VTC. It adjusts the intake cam's timing for optimal performance throughout the power band. However, the SR20VET actually changes valve lift, like VTEC.