When does VTEC engage on a k24z3?
03-11-2009, 06:42 PM
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03-18-2009, 07:21 PM
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Re: vtech engages when
It varies depending on several computer inputs (ECT, TPS, MAP, RPM). It's just changing valve timing, duration and lift...Why does it matter when it "engages" or switches from low to high? You will here a louder groan and slightly quicker acceleration, it's difficult to feel it "engage" and even difficult to hear depending on the engine. I take it this must be some sort of an argument resolve? haha
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03-25-2009, 08:32 PM
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Re: vtech engages when
on my 03 4 cyl accord, its hard to tell when it engages, compared to my b series that just screams vtec!!! I know what you mean, I would like to know as well!
03-25-2009, 10:35 PM
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Re: vtech engages when
he was saying this because the op miss spelled vtec. Vtech is a phone make company that makes them for home use. Its also a kids video game toy, for learning. So this guy might have vtec like the rest of us but not vtech... no one should have vtech in their motors if they do then somethings wrong.
03-26-2009, 08:02 AM
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04-06-2009, 10:57 PM
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Re: When does VTEC engage on a k24z3?
well..
on my K24Z3 with an intake i can definitely here it engage around 5000+-, also depends on whether my foot is really down or not.
on my K24Z3 with an intake i can definitely here it engage around 5000+-, also depends on whether my foot is really down or not.
04-12-2009, 06:41 AM
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Re: vtech engages when
04-12-2009, 07:20 AM
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Re: When does VTEC engage on a k24z3?
the k24 motors are not performance motors like the K20 and the older b series with vtec. The vtec in k24s is tuned for economy. thats why its not that noticable unless you have an intake or exhaust. and the k series have i-vtec so it actually different stages of vtec. Thats why its also harder to tell, plus i-vtec is supposed to be smoother than just regular vtec
http://www.elitecm.net/forums/viewtopic.php?f=9&t=170
I also believe it has to do with the camshafts the "performance" k-series have 3 lobed cams and the "economy" k-series have 2 lobed cams. not 100% sure on that though
http://www.elitecm.net/forums/viewtopic.php?f=9&t=170
I also believe it has to do with the camshafts the "performance" k-series have 3 lobed cams and the "economy" k-series have 2 lobed cams. not 100% sure on that though
04-12-2009, 11:50 AM
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Re: When does VTEC engage on a k24z3?
the k24 motors are not performance motors like the K20 and the older b series with vtec. The vtec in k24s is tuned for economy. thats why its not that noticable unless you have an intake or exhaust. and the k series have i-vtec so it actually different stages of vtec. Thats why its also harder to tell, plus i-vtec is supposed to be smoother than just regular vtec
http://www.elitecm.net/forums/viewtopic.php?f=9&t=170
I also believe it has to do with the camshafts the "performance" k-series have 3 lobed cams and the "economy" k-series have 2 lobed cams. not 100% sure on that though
http://www.elitecm.net/forums/viewtopic.php?f=9&t=170
I also believe it has to do with the camshafts the "performance" k-series have 3 lobed cams and the "economy" k-series have 2 lobed cams. not 100% sure on that though
04-13-2009, 08:31 AM
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04-13-2009, 08:50 AM
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Re: When does VTEC engage on a k24z3?
From k20a.org:
Originally Posted by k20a.org
The K-series uses a DOHC valvetrain, which utilizes roller rockers to reduce friction. The VTEC system on engines like the K20A3 is only on the intake cam, and at low RPM when not engaged, allows the engine to function as a 12-valve engine, opening only one intake valve so that the air swirls for better combustion. This VTEC system was designed with fuel economy in mind. In engines like the K20A2 found in the RSX Type-S, The VTEC system always allows the motor to run as a 16 valve engine, and when VTEC engages, its on both the intake and exhaust rockers, and opens all 4 valves even more at high RPM
The big difference between the A2 and the other K series engines is how the cam-switching part of iVTEC works. The A2 uses a cam-switching technique familiar to the most Honda fans. Extra rocker arms are slaved to one of two cams, increasing lift and duration at higher revs for better high-end power. The other engines use a version tuned for fuel efficiency. One intake valve is essentially closed when "off-cam," and when the switch happens, the closed valve is just slaved to the same cam the opening one does. No higher lift or duration, but some pretty good fuel economy and emissions figures.
The K20A2 in the Type-S works the way you expect VTEC to work. The two camshafts are equipped with three cam lobes and rocker arms for each cylinder's pair of intake and exhaust valves. At 5800 rpm, oil pressure activates pins that lock the outer rocker arms to the center arm. This forces both valves to use the higher lift, longer duration center camshaft profile. However, this is augmented by VTC on the intake side, which manipulates the timing of the cam itself. This can be used to augment torque, reduce emissions or a variety of different things depending on what the computer thinks is best at the time. The RSX's K20A3, the Si's K20A and the CR-V's K24A1 use i-VTEC differently. First, it only operates on the intake valves. But even then, the philosophy is changed. Until the VTEC threshold is reached, the lesser K engines essentiality only use one intake valve per cylinder. The other is opened just a crack, enough to keep fuel from pooling behind the valve, but that's about it. In addition, the VTC is tuned primarily to keep emissions as low as possible. All this weirdness results in excellent swirl inside the combustion chamber and very efficient combustion. It's great for fuel efficiency and low emissions. However, it isn't so great for driving fun, as the engine inhales less deeply and revs lower.
The big difference between the A2 and the other K series engines is how the cam-switching part of iVTEC works. The A2 uses a cam-switching technique familiar to the most Honda fans. Extra rocker arms are slaved to one of two cams, increasing lift and duration at higher revs for better high-end power. The other engines use a version tuned for fuel efficiency. One intake valve is essentially closed when "off-cam," and when the switch happens, the closed valve is just slaved to the same cam the opening one does. No higher lift or duration, but some pretty good fuel economy and emissions figures.
The K20A2 in the Type-S works the way you expect VTEC to work. The two camshafts are equipped with three cam lobes and rocker arms for each cylinder's pair of intake and exhaust valves. At 5800 rpm, oil pressure activates pins that lock the outer rocker arms to the center arm. This forces both valves to use the higher lift, longer duration center camshaft profile. However, this is augmented by VTC on the intake side, which manipulates the timing of the cam itself. This can be used to augment torque, reduce emissions or a variety of different things depending on what the computer thinks is best at the time. The RSX's K20A3, the Si's K20A and the CR-V's K24A1 use i-VTEC differently. First, it only operates on the intake valves. But even then, the philosophy is changed. Until the VTEC threshold is reached, the lesser K engines essentiality only use one intake valve per cylinder. The other is opened just a crack, enough to keep fuel from pooling behind the valve, but that's about it. In addition, the VTC is tuned primarily to keep emissions as low as possible. All this weirdness results in excellent swirl inside the combustion chamber and very efficient combustion. It's great for fuel efficiency and low emissions. However, it isn't so great for driving fun, as the engine inhales less deeply and revs lower.
04-13-2009, 07:31 PM
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Re: When does VTEC engage on a k24z3?
quoted from another source:
The K24Z2 and K24Z3 also have a radical, new design for the head on the exhaust side. instead of having an exhaust manifold with four individual exhaust ports for each combustion chamber, a sort of pyramid shaped collector diverts all the exhaust into a single square exit. this was done for various reasons such as bolting the catalytic converter close to the engine for faster heating in cold starts and doing away the header for cost reduction.
04-14-2009, 01:30 PM
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Re: When does VTEC engage on a k24z3?
i understand the difference, but why would the exhaust manifold limit the ability for the head to be swapped out? is the block different somehow so that it can work with the pyramid manifold?
i guess at that point i might as well buy a new car if i really want to boost the power.