VVTI Engagement?
01-27-2006, 05:55 AM
#3
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im pretty sure it works da same way as da civic si's wit vvti....when u full throttle it. i knoe with honda they have 2 kinds of vvti...da ones that engage when u full throttle it on the civic and the rsx type s i think engages in two stages at different rpms.
01-27-2006, 12:31 PM
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Originally Posted by unsungfate
Actually, I believe the valve timing kicks in around 4 thousand RPM. I think so becuase thats when the tone of the engine changes and starts roaring.
01-27-2006, 01:04 PM
#7
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Originally Posted by unsungfate
Actually, I believe the valve timing kicks in around 4 thousand RPM. I think so becuase thats when the tone of the engine changes and starts roaring.
01-27-2006, 01:04 PM
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vtech is alot diffrant then what we have
vetech opens up a nother set of valves (only in vtec-e) all though they do all adjust timing (vtec-e, dohc vtec, vtec, and 3 stage vtec) if any thing is close to vtec it would probly be a 2zz with vvtli although it does work way diffrant since spacers slide on the lobes rather then rather then switching to a diffrant profile like hondas
and to my understanding the vvti works at all rpms for greater fuel econamy and greater performance up top more tword fuel econamy stock though so that could use some adjusting (camcon)
not 100% sure on this info but correct me if im wrong since this is all just my understanding
vetech opens up a nother set of valves (only in vtec-e) all though they do all adjust timing (vtec-e, dohc vtec, vtec, and 3 stage vtec) if any thing is close to vtec it would probly be a 2zz with vvtli although it does work way diffrant since spacers slide on the lobes rather then rather then switching to a diffrant profile like hondas
and to my understanding the vvti works at all rpms for greater fuel econamy and greater performance up top more tword fuel econamy stock though so that could use some adjusting (camcon)
not 100% sure on this info but correct me if im wrong since this is all just my understanding
01-27-2006, 01:35 PM
#9
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Re: VVTI Engagement?
Originally Posted by toyota_scion_tc
When does the VVTI begin working on our cars. Am I correct to belive it works all the time even at idle or is there a certain rpm we need until it engages.
you are in vvt-i right around 2,000rpm but it can and usually is a constant system. Its job is to adjust with driving habits, to deliver best results with economy and performance mixture.
Where as v-tec and i-vtec is designed strictly as a performance guide, and is set at a specific rpm and does not change without a vtec controll or stand alone.
01-27-2006, 01:38 PM
#10
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Originally Posted by unsungfate
Actually, I believe the valve timing kicks in around 4 thousand RPM. I think so becuase thats when the tone of the engine changes and starts roaring.
I might also point out thats near where peak whp/wtq is so it may feel like it has to do with vvt-i but in reality, has nothing to do with it.
01-27-2006, 02:21 PM
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Originally Posted by dachmo
V-tec does not open different valves, it switches cam lobes to open the same valves more.
A non-VTEC-E engine normally has one single cam profile for the intake valves. A VTEC-E engine has two different intake cam profiles. At low RPMs, each intake valve works from its own intake cam profile. One of the intake cam profiles is very normal looking. The other one, however, is almost perfectly round, with just enough profile to it so that it pushes the valve open just enough to avoid pooling of fuel above the valve lip. Therefore at low RPM, only one intake valve is opening and closing. Most of the intake fuel and air are squeezed through this one valve, resulting in a good swirling effect in the cylinder. The swirling effect optimizes the fuel/air mixture, thus allowing a very lean mixture to be used.
As the RPMs increase, the demand for more fuel/air rises as well. Once a certain RPM is reached (approximately 2500RPM for the Civic HX), the one-intake-valve configuration starts to become a significant intake restriction. At this time, a solid pin is pushed through the two intake valve rocker arms, thus binding the two rocker arms into a single unit. This causes both intake valves to open and close according to the normal cam profile, while the almost-round cam profile is no longer used.
As the RPMs increase, the demand for more fuel/air rises as well. Once a certain RPM is reached (approximately 2500RPM for the Civic HX), the one-intake-valve configuration starts to become a significant intake restriction. At this time, a solid pin is pushed through the two intake valve rocker arms, thus binding the two rocker arms into a single unit. This causes both intake valves to open and close according to the normal cam profile, while the almost-round cam profile is no longer used.
im building a d so i have reasearched the crapy vtec alot
01-27-2006, 02:24 PM
#17
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Originally Posted by aarontrini85
Originally Posted by dachmo
V-tec does not open different valves, it switches cam lobes to open the same valves more.
A non-VTEC-E engine normally has one single cam profile for the intake valves. A VTEC-E engine has two different intake cam profiles. At low RPMs, each intake valve works from its own intake cam profile. One of the intake cam profiles is very normal looking. The other one, however, is almost perfectly round, with just enough profile to it so that it pushes the valve open just enough to avoid pooling of fuel above the valve lip. Therefore at low RPM, only one intake valve is opening and closing. Most of the intake fuel and air are squeezed through this one valve, resulting in a good swirling effect in the cylinder. The swirling effect optimizes the fuel/air mixture, thus allowing a very lean mixture to be used.
As the RPMs increase, the demand for more fuel/air rises as well. Once a certain RPM is reached (approximately 2500RPM for the Civic HX), the one-intake-valve configuration starts to become a significant intake restriction. At this time, a solid pin is pushed through the two intake valve rocker arms, thus binding the two rocker arms into a single unit. This causes both intake valves to open and close according to the normal cam profile, while the almost-round cam profile is no longer used.
As the RPMs increase, the demand for more fuel/air rises as well. Once a certain RPM is reached (approximately 2500RPM for the Civic HX), the one-intake-valve configuration starts to become a significant intake restriction. At this time, a solid pin is pushed through the two intake valve rocker arms, thus binding the two rocker arms into a single unit. This causes both intake valves to open and close according to the normal cam profile, while the almost-round cam profile is no longer used.
im building a d so i have reasearched the crapy vtec alot
01-27-2006, 02:31 PM
#19
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Originally Posted by killerxromances
Originally Posted by ScionDad
Listen here fellas....it only works when the engine is running. 
jk.
I also know I get much better gas mileage when it sits in my garage
