VVT
#1
02-17-2008, 03:56 PM
VVT
i searched for VVT and found many things but those threads are old and maybe by now some sort of chip has to be on the market for vvt to kick in as if it was v-tech in honda, without going piggy back.
#2
02-17-2008, 04:35 PM
RE: VVT
Mazdas sequential valve timing is a lot different than hondas v-tec
great link for vvt
http://www.mazda6tech.com/index.php?...4&Itemid=1
"Because camshafts are optimized for a single RPM, it would be beneficial if an engine could use two camshafts- one optimized for low RPMs, and the other optimized for high RPMs. Somewhere in-between, the engine would switch from one cam to the other.
This, in essence, is what Honda's VTEC does. VTEC allows two different cam profiles on the same shaft to switch nearly instantly, giving two very distinct timings. At higher RPMs, the valves open longer, faster, and higher for better breathing. At lower RPMs, the shorter valve openings keep the charge of incoming air at high velocity. The intake and exhaust valve opening times will overlap as RPMs rise, recycling some of the charge the outgoing air creates.
Mazda's engines are not quite so sophisticated. Mazda uses a static camshaft, however the shaft is attached to a cog that can advance or retard its rotation. The valves can open sooner or later, but never longer, faster, or higher. The cog is controlled by a precision oil pump, called the oil control valve (OCV). The car's computer tells the OCV how much to advance or retard the intake timing based on a number of input parameters, such as pedal pressure, engine temp, and more."
great link for vvt
http://www.mazda6tech.com/index.php?...4&Itemid=1
"Because camshafts are optimized for a single RPM, it would be beneficial if an engine could use two camshafts- one optimized for low RPMs, and the other optimized for high RPMs. Somewhere in-between, the engine would switch from one cam to the other.
This, in essence, is what Honda's VTEC does. VTEC allows two different cam profiles on the same shaft to switch nearly instantly, giving two very distinct timings. At higher RPMs, the valves open longer, faster, and higher for better breathing. At lower RPMs, the shorter valve openings keep the charge of incoming air at high velocity. The intake and exhaust valve opening times will overlap as RPMs rise, recycling some of the charge the outgoing air creates.
Mazda's engines are not quite so sophisticated. Mazda uses a static camshaft, however the shaft is attached to a cog that can advance or retard its rotation. The valves can open sooner or later, but never longer, faster, or higher. The cog is controlled by a precision oil pump, called the oil control valve (OCV). The car's computer tells the OCV how much to advance or retard the intake timing based on a number of input parameters, such as pedal pressure, engine temp, and more."
#5
02-18-2008, 02:17 PM
RE: VVT
im pretty sure that the both the Duratec 20 and Duratec 23 are both Mazda designs and Ford manufactures them for the Focus and a few other models. the Ford models lack VVT however.
correct me if im wrong, please.
correct me if im wrong, please.
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