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TheFranchise
03-04-2006, 03:20 PM
Just a quick question

What are the differences between

* VTEC
* VVTi
* MIVEC

Honda, Toyota and Mitsu all have these 'vecs', are they all similar in function or totally different?

Zdster
03-04-2006, 03:32 PM
Here you go:


VTEC: http://en.wikipedia.org/wiki/VTEC
VVTI: http://en.wikipedia.org/wiki/VVT-i
MIVEC: http://en.wikipedia.org/wiki/MIVEC

They are all variations on a similar theme.

TheFranchise
03-04-2006, 03:37 PM
thanks mate

Stoosh
03-04-2006, 03:44 PM
there is nothing like the sound of VTEC baby!! not that i would know...unless ahmed is driving past me!

EK9_boi
03-04-2006, 05:12 PM
VTEC rules. Mivec copies, vvt-i compromises ah...economizes. ;)

StrawberryFace
03-04-2006, 05:47 PM
but vvti-l owns ;) lol

socheerio
03-04-2006, 06:10 PM
What about Double VANOS and Valvetronic?

aaronng
03-04-2006, 06:25 PM
The best place to learn about all this is at http://www.autozine.org/technical_school/tech_index.htm

You have VTEC, VTEC-E, i-VTEC, VVTi, VVTLi, MIVEC, VVL, VANOS, Valvetronic, VarioCam everything you want to know about.

Basically you have:
Cam changing: VTEC, VVTLi, MIVEC, VVL.
Variable valve: VTC part of i-VTEC, VVTi and Dual-VVTi, Variocam, Vanos and Double Vanos, everyone else and their uncle's car with variable valve timing like Subaru, Jaguar, Mercedes, Renault, Ford Falcon BF, Ferrari.
Variable valve and cam changing: i-VTEC, VVTLi, Variocam Plus.
Variable valve with duration variation: VVC
Variable valve with duration and lift changing: Valvetronic.


BTW, that VTEC sound that everyone likes, you get it by putting on a CAI or SRI, coupled with an aggressive cam profile. Of couse your low RPM drivability will be SH*T. That's why VTEC is good. We can have our cake and eat it. And don't look at me, I get more torque when I'm not in high cam. *CRIES*

iamhappy46
05-04-2006, 11:02 AM
What about NEO VVL on the Nissan SRxxVE motors?? Has independant control of the camshaft lobe change points ;)

aaronng
05-04-2006, 01:35 PM
What about NEO VVL on the Nissan SRxxVE motors?? Has independant control of the camshaft lobe change points ;)
Yeah, Neo VVL is cool. It's cam change on both intake and exhaust cams, but it can switch to high cam at different RPM for each shaft. Example:
low RPM: low intake cam, low exhaust cam.
medium RPM: high intake cam, low exhaust cam.
high RPM: high intake cam, high exhaust cam.

Zdster
05-04-2006, 02:00 PM
Thats pretty cool. I take it that it is all electronically controlled?

aaronng
05-04-2006, 02:06 PM
Usually cam change is initiated by RPM through the ECU and it triggers the solenoid that sends high pressure oil to lock the high cam pins. On Honda's DOHC VTEC, you have 1 solenoid and 1 high pressure oil circuit. I think with Neo VVL, it has 2 solenoids and 2 individual circuits. Of course, that makes it more expensive than VTEC. :)

iamhappy46
05-04-2006, 08:37 PM
Only one oil supply line to the solenoid(located at end of intake camshaft) but 2 solenoids control the seperate camshafts.

Example of what a modified SR20VE looks like here (http://www.sr20forum.com/showpost.php?p=1429837&postcount=1)

aaronng
05-04-2006, 09:15 PM
Yeah, 2 solenoids needs 2 oil circuits. One circuit for intake, one circuit for exhaust. And yes too, 1 oil line supplies both circuits.

notorious_ahmie
06-04-2006, 08:17 PM
there is nothing like the sound of VTEC baby!! not that i would know...unless ahmed is driving past me!


thats very tru!

StrawberryFace
06-04-2006, 10:39 PM
Toyota now have Dual VVTi :)

aaronng
06-04-2006, 11:17 PM
Toyota now have Dual VVTi :)
Every Celica also has Dual VVTi, plus lift! :)