Another CVVT question, Non-badge Related

[BColeman]

Okay, someone in the other thread said the CVVT basically adjusts timing of the valve(s).

So, I've got questions, if anyone has yet to make heads or tails of CVVT:

1) Which valves stay open longer: Int. or Exh.?

2) Do the valves stay open longer, or open more times?

3) With it being continuous, what are the requirements for it to "activate"?

4) With it being continuous, does the timing of the valves change that often?

AND THE BIG QUESTION:

What would happen if it was just unplugged? Appearance says it requires oil to operate, similar to VTEC. If it was just unplugged, at the solenoid, would this through a CEL (doesn't matter to me, since I already have one from the headers), would it disrupt the oil flow, would I have any timing of the valves other than what ever it's set at with the cam gears?

I know that there are no ways to tune CVVT, YET. I'm sure Korea tuners are working diligently on this (not), but since we are talking valve timing, not additional lobes on the sticks, is there really even a way to tune it?

[05TidalWave]

From what I understand Continuous Variable Valve Timing means Int AND Exh are open for longer AND shorter periods of time depending on the engines needs at the moment. It's meant to help with power and mileage... As for the other questions... Ford?

[Mahonroy]

I believe you can simply unplug it but I don't think you will get any performance benifit out of it. Here is a shot I took where you can see the CVVT connected to the cams, as well as where the harness plugs into it, I don't see how it would restrict oil or anything...

http://www.jattus.com/Performance/q6.jpg

[carbonman]

I know for a while the Koreans were disconnecting the CVVT for turbo apps. when it (CVVT) first came out that is I don't know if they utilize it now though

[ricerrx7]

There is no way for the CVVT to change the duration of the valve openeing. It just adjusts when the valve is open.

[pjc6281]

I dont think it helps power cause the 03 elantras have the same rated hp as the the new ones. But i do know it makes a straighter torque curve. I basic cvvt controls intake and exhaust at the same time and has set programs depending upon the throttle position. I know toyota just came out with Dual CVVT in there new avalon v6 engine. I believe it controls the intake and exhaust valves independantly. From that system the engine got a performance boost.

[fgummett]

article on VVT... http://www.streetracersonline.com/articles/camshafts/3.php

Remember that an engine is basically a glorified air pump and, as such, the most effective way to increase horsepower and/or efficiency is to increase an engine's ability to process air. There are a number of ways to do this that range from altering the exhaust system to upgrading the fuel system to installing a less-restrictive air filter. Since an engine's valves play a major role in how air gets in and out of the combustion chamber, it makes sense to focus on them when looking to increase horsepower and efficiency.

This is exactly what Honda, Toyota and BMW and quite a number of other manufacturer's have done in recent years. By using advanced systems to alter the opening and closing of engine valves, they have created more powerful and clean burning engines that require less fuel and are relatively small in displacement.

[Jonny666]

From what i can see of that photo the exhaust cam is connected directly to the Timing belt and the cvvt adjusts the timing chain to adjust the intake cam therefore altering cam overlap. Remember high overlap = good top end power and low overlap = good low end power. that's what flattened out the tourque curve. the reason the turbo guys dont like this is turbo's HATE overlap and it kills their power.

[bfgoedeke]

The overlap also provide an EGR effect. When you open the intake valve sooner, a trace amount of exhaust gas remains in the cylinder. Hence, acting as an EGR valve without actually needing one. More pollution ( emissions ) control.....