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Discussion Starter #1
Hows it work?

What are the benefits? (pros/cons)

And when does it kick in?


thanks guys!
 

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I can't give you a technical answer about over head cam version but i can give you a basic idea on how it works. Rhodes makes a lifter for the conventional engine that has a bleed slot in the inside of the lifter that also for oil to bleed out thus not allowing the valve to open as high or stay open as long but as the engine speeds up the oil pressure and volumne increases to the point that the slot can not loose enough oil to effect the lift or duration of the valve thus allowing the engine to run as if there was no slot. A engine with less lift and duration on the valve gives more power at a lower rpm so as you can see as the engine speeds up the power band moves up so the major effect is the engine has a broader power band. By the time the engine reached 3500RPM the bleed slot had no effect, it allowed you to run a higher lift and duration cam with out losing your bottom end power.Hope this helps with your question.
 

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Aimer said:
Hows it work?

What are the benefits? (pros/cons)

And when does it kick in?


thanks guys!
Depends on which system you're referring to.

If you're asking about Hyundai's VVT system, the truth is I don't think anybody knows for sure yet. What I do know is that it doesn't "kick in". Systems that kick in are lift-adjusting, such as Honda's VTEC and Toyota's VVTL-i. Our system is more similiar to Toyota's VVT-i. Throughout the RPM range, the computer constantly alters the timing of the intake and exhaust valves, making the engine run smoother and more efficiently.

I haven't had a chance to dyno a stock CVVT car yet, but from my "butt dyno", I can tell you that the CVVT makes the engine full much smoother and it seems to pull harder in the higher RPMs than the older non-CVVT Beta engines did.

[EDIT]
I've described how Honda's VTEC and Toyota's VVTL-i works previously on HyundaiPerformance.Com. Here's a link if you want to read up on it:

http://www.hyundaiperformance.com/forums/topic.php?t=1240#7068
http://www.hyundaiperformance.com/forums/topic.php?t=12609#96124
http://www.hyundaiperformance.com/forums/topic.php?t=20436#157694
[/EDIT]
 

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that's the CVVT info from Hyundai

http://www.hmaservice.com/recent/7/03-36-014-012/03-36-014-01.pdf

page 8

5. CVVT (CONTINUOUSLY VARIABLE VALVE TIMING) SYSTEM

The CVVT unit is mounted on the exhaust camshaft and controls the intake valve timing by advancing and retarding the intake camshaft in relation to the exhaust camshaft. The Powertrain Control Module (PCM) controls the amount of timing advance up to 40° (crank angle) 20° (cam angle) depending on engine load and speed. The three main advantages of the CVVT system are:

1. Improved performance at high rpm and increased torque at low rpm
through increased volumetric and thermodynamic efficiencies.

2. Improved fuel economy due to better cylinder charge achieved through increased valve overlap.

3. Reduced NOx emissions due to the EGR effect created by optimizing valve
overlap.
EDIT:
internal exhaust gas re-circulation (EGR) effect

and here one can see the real difference
non-cvvt dynochart next to the CVVT dynochart
 

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I feel it kick in just under 5K, but above 4900. It's really cool.
 

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what model years is equipped with it?
 

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I think 04 to 08 models, inline 4 only. Deltas dont have any form of variable valve timing. But the updated version called the Mu does
 

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According to this, CVVT didnt become available until the 2005 models

The Tiburon GS is fitted wîth Hyundai's high-tech 2.0-liter, 16-valve DOHC, four-cylinder engine. For 2005, Continuously Variable Valve Timing (CVVT) has been added for even more precise control of engine emissions.

Source:

http://www.conceptcarz.com/vehicle/z8837/2005-Hyundai-Tiburon.aspx.aspx
 

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Wow i didnt realize either. 2004. Wonder how long he dug to find this lol. Closed
 
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