What's the CVVT System actually do?

[ColeIketani]

Now I know that the new 2004 I4 Tibs are equipped with a Continuous Variable Valve Timing system in them. I'm not sure excatly what that system does.

From what I have seen this system has a slight increase in either horsepower or torque (This is because some of the readings of the 03' Tibs are a bit off balanced)



2003 I4 Tiburon
Either

OPTION:A

Horsepower 140 @ 6000 RPM
Torque (lb-ft) 133 @ 4500 RPM

or

OPTION:B

Horsepower 134 @ 6000 RPM
Torque (lb-ft) 132 @ 4500 RPM


2004 I-4 Tiburon with the CVVT System
Horsepower 138 @ 6000 RPM
Torque (lb-ft) 136 @ 4500 RPM




So 1) does anyonw know what the CVVT does
and 2) is the horsepower of the '03 Tib really projected as option A or option B? I mean ignoring the dyno tests

I know that the V6 Tibs have an increase of 2hp but I don't think that it has the CVVT.

[Midnight_Outlaw]

It is B 134hp with 132lb-ft

Ok so i have not seen exactly how it works yet but im sure it is alot like the one on the ferri's and other Continuous Variable systems, were the cam is tapered and as the rpm's increse or decrese it auctly moves the cam to the one way or the other to change the valve timing.

Car makers have to pick a optimioum (but spelled correctly [opt-ta-mum]) rpm were the valve timing is ment for that rpm and it produces the best hp it can make, you pick a rpm to high and the car will stall out at a idle you pick one to low and your not getting much power. With the VTEC/CVVT systems they can still pick a rpm really high and have a great idle.

But becides that if you have ever looked at a dyno test you see it goes up and up untill it hits a peak then it goes down. thats because of the cam. That is the peak rpm, like on the tibs its 6000. On wankles it goes up and up and up and up but thats a diffrent story all together.

SO any hoo it changes the valve timing to best meet the needs of that rpm to get as much power as it can out of it.

But these systems are flawed they can only adjust it so much. The best way and what they are tring to do is not use cams and use silnoids to make it truely infinitly verible.

If you goto www.howstuffworks.com they explain it awesome they even have videos they show the VTEC system also.

I hope my over complex bable helps

[ColeIketani]

well I am a little disapointed that it is Option B (unless your wrong.....heh..cause why does Hyundai say 140?) Anyway, thanks for the definition of the CVVT system.

[Midnight_Outlaw]

140hp was from the older style the 2001 and before type. But dont fear cuz you make more low end and mid range power.

[tibby01]

this site explains vtec great. cvvt works on the intake valves only.

http://www.leecao.com/honda/vtec/whatsvtec.html

[Midnight_Outlaw]

Is the hyundai system only on the intake valves? well that kind of sucks, But its better then nothing. Hopefuly the next version will be on bolth valves.