VVT in 2.2?
#5
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Is VVT that good? What does it do exactly. I have a 2.4 and have no idea what the VVT actually does. I know its Variable Valve Timing. But what does it do to to actually help?
#6
"The new variable valve timing system uses electronically controlled hydraulic camshaft phasers to alter the relationship of the intake and exhaust camshafts as much as 50 degrees relative to the crankshaft." This allows the PCM to maximize the power output throughout the RPM range giving the 2.4L a relatively flat torque curve.
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Yup, the more gadgets on the motor... the more risk to break... But Honda and Toyota have been using them for years... so I wouldn't worry about it too much.... as long as GM didn't screw things up again!
#9
I'm old school
Here's how it physically works. Your valves, which allow gas in and exhaust out, open and close in time with the turning of the engine. This is accomplished by means of a chain wrapped between the crankshaft and the camshafts. The camshaft is the part that actually opens the valves. The timing is normally a fixed thing, since it is a chain, when one gear turns (the crank), so does the other (the cam).
With Variable Valve Timing, its all the same, except they put a degree of "slack" in the chain which is then kept tight by tensioners. If you put tension on one side of the chain, the cams turn in one relative timing with the crank. If you shift the tension to the other side of the chain, the cams timing changes along with the shift.
The reason for doing this has to do with RPM. The efficiency of fluid movement (gas in, exhaust out), changes with changes in RPM. A fixed valve timing arrangement picks a setting that will give the best possible operation through all ranges of RPM. With VVT, the engine can actually change the valve operation timing to accomodate the current engine RPM and hence be more effecient and deliver more power.
You can not modify an engine to become VVT capable. It has to be part of the core engine design. Its like asking if you can modify our engines to be DVD players or something.
With Variable Valve Timing, its all the same, except they put a degree of "slack" in the chain which is then kept tight by tensioners. If you put tension on one side of the chain, the cams turn in one relative timing with the crank. If you shift the tension to the other side of the chain, the cams timing changes along with the shift.
The reason for doing this has to do with RPM. The efficiency of fluid movement (gas in, exhaust out), changes with changes in RPM. A fixed valve timing arrangement picks a setting that will give the best possible operation through all ranges of RPM. With VVT, the engine can actually change the valve operation timing to accomodate the current engine RPM and hence be more effecient and deliver more power.
You can not modify an engine to become VVT capable. It has to be part of the core engine design. Its like asking if you can modify our engines to be DVD players or something.
#11
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Originally Posted by Halfcent
Here's how it physically works. Your valves, which allow gas in and exhaust out, open and close in time with the turning of the engine. This is accomplished by means of a chain wrapped between the crankshaft and the camshafts. The camshaft is the part that actually opens the valves. The timing is normally a fixed thing, since it is a chain, when one gear turns (the crank), so does the other (the cam).
With Variable Valve Timing, its all the same, except they put a degree of "slack" in the chain which is then kept tight by tensioners. If you put tension on one side of the chain, the cams turn in one relative timing with the crank. If you shift the tension to the other side of the chain, the cams timing changes along with the shift.
The reason for doing this has to do with RPM. The efficiency of fluid movement (gas in, exhaust out), changes with changes in RPM. A fixed valve timing arrangement picks a setting that will give the best possible operation through all ranges of RPM. With VVT, the engine can actually change the valve operation timing to accomodate the current engine RPM and hence be more effecient and deliver more power.
You can not modify an engine to become VVT capable. It has to be part of the core engine design. Its like asking if you can modify our engines to be DVD players or something.
With Variable Valve Timing, its all the same, except they put a degree of "slack" in the chain which is then kept tight by tensioners. If you put tension on one side of the chain, the cams turn in one relative timing with the crank. If you shift the tension to the other side of the chain, the cams timing changes along with the shift.
The reason for doing this has to do with RPM. The efficiency of fluid movement (gas in, exhaust out), changes with changes in RPM. A fixed valve timing arrangement picks a setting that will give the best possible operation through all ranges of RPM. With VVT, the engine can actually change the valve operation timing to accomodate the current engine RPM and hence be more effecient and deliver more power.
You can not modify an engine to become VVT capable. It has to be part of the core engine design. Its like asking if you can modify our engines to be DVD players or something.
#14
with enough fabrication, anything is possible. it would be quite a challenge and an interesting project.
i thought the vvt maximized fuel economy, not power. didnt the 2.4l eco have the extra power from the increased displacement?
there is a guy on ecotecpower.com who is trying this, maybe do a search there.
i thought the vvt maximized fuel economy, not power. didnt the 2.4l eco have the extra power from the increased displacement?
there is a guy on ecotecpower.com who is trying this, maybe do a search there.
#16
Originally Posted by celicacobalt
vvt definately helps with power
i dont see hp increases more than a couple hp coming from a stock engine with a timing change.
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well i think with mods it makes more of a difference since the vvt can adjust to them and make better use of them with the right timing instead of a universal timing for all rpms
#18
Originally Posted by celicacobalt
well i think with mods it makes more of a difference since the vvt can adjust to them and make better use of them with the right timing instead of a universal timing for all rpms
#19
Vvt
VVT can spread the power band further, by advancing the cams low end power is improved and by retarding them high end power is improved. VTEC is completely different, when VTEC comes in another set of cam lobes is engaged which open the valves longer and/or further.
#20
Originally Posted by giovanhalen
VVT can spread the power band further, by advancing the cams low end power is improved and by retarding them high end power is improved. VTEC is completely different, when VTEC comes in another set of cam lobes is engaged which open the valves longer and/or further.
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