View Full Version : Variable Valve Timing (VVT) VS VTECH


[-GibZ-]
August-12th-2004, 09:19 PM
i am wondering if the mazda variable valve timing is the same thing then Vtech i know how vtech works (switch of cam a 4500 rpm) but couldnt find good information about VVT as i can see in my 3 sport the engine seem to get excited at high RPM too.. (110 km/h in second gear :) ) can someone explain it to me or give a link please?

Roddimus Prime
August-13th-2004, 12:20 AM
Vtech is honda's name for valve timing....VVT is mazda's name for variable valve timing. VVT-i is toyota's name for variable valve timing WITH intelligence.

It's all 100% the exact same thing. It just changes the cam profile at a pre-determined point to allow the engine to breathe better based on its current rpms.

macdaddyslomo
August-13th-2004, 01:24 AM
no its not Matty....Mazda's S-VT is a continuously variable cam timing system....V-TEC is LOW-TECH(it's basically on or off) compared to S-VT..It is however similar to the VVT-I...however note torque numbers on the Mazda S-VT engines compared to Toyota and Honda's Variable Valve timing systems...Mazda's have MUCH more torque :bt:

ZOOM_X_TWO
August-13th-2004, 01:52 AM
but vtec is way cooler! Mmm i can still smell the vtec from my GSR...ahh the good old days.

[-GibZ-]
August-13th-2004, 06:38 AM
ok thx macdaddy,i knew that it wasnt the same they can't copy the honda technology...
VVT is relly defficient because compare to a P5 the performance is much better

Roddimus Prime
August-13th-2004, 09:24 AM
no its not Matty....Mazda's S-VT is a continuously variable cam timing system....V-TEC is LOW-TECH(it's basically on or off) compared to S-VT..

I knew that but I was trying to keep it simple so no'one gets confused. Also, I'm a lazy poster and didn't feel like going into specifics but the toyota vvt-i is also continuously variable like the mazda and even the new hondas now have it.

fdb
August-16th-2004, 12:08 PM
Mazda's system continuosly varies valve timing, but does NOTHING to lift and duration of the cam. Those are constant.

The latest version of VTEC, found in the RSX, varies timing continuosly like Mazda's system and still switches cam lobes at 6000rpm or whatever it is.....

Advantage Honda.

mazda3team
August-25th-2004, 10:42 AM
Mazda's system continuosly varies valve timing, but does NOTHING to lift and duration of the cam. Those are constant.

The latest version of VTEC, found in the RSX, varies timing continuosly like Mazda's system and still switches cam lobes at 6000rpm or whatever it is.....

Advantage Honda.


Correct Honda's is still more advanced interms of internal engine timming controling with its cam profiles. However Mazda has along with their static cam shaft that does kick its timming at 4500rpm, is VAD (Varible Air Duct) VLIM (Varible Length Intake Manifold) VTCS (Varible Tumble Control System) VVT (Varible Intake Valve Timming ( Cam-phasing intake cam only). These are all addition ways to give control to the static VVT. Our VVT is more benificial then Hondas in the sence that it give us more torque at a more brodem RPM range, but not controlled. The control comes in to play wth the others mentioned above.

So in essence instead what Mazda has done was realize that the controling cam while timmimg is not going to acheive the best power gains in terms of torque. They decided to let put controled valves in the intake runners and Air ducts of the air intake system. This give the flexiblity lost with none controled cams but the added full torque with the static VVT.

his is another form of valve tuning, and it works on the principles of Helmholtz Resonance. This was created in the 1991 Mazda 787B Rotory car that was banned. It was the first rotory & Japanese car to win the Lemans 24hr race.