Acura Legend Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
93 Posts
What is the difference in a vtech engine and the legend engine
Vtec has variable valve timing in the upper range of the revs to keep the power at its peak.
Legend motor dosnt have that it has 1 setting from low end to top end.
legends can take a accord off the line but accord will open up in the upper range
 

·
Dont Catch
Joined
·
4,408 Posts
Vtec has variable valve timing in the upper range of the revs to keep the power at its peak.
Legend motor dosnt have that it has 1 setting from low end to top end.
legends can take a accord off the line but accord will open up in the upper range
be a little more specific than that... not all accords came with vtec. and accords arent the only ones with vtec.

legendatwork: heres some pages you can look at to see the difference between SOHC, DOHC, and how the honda VTEC system works
Howstuffworks "Camshaft Configurations"

How VTEC Works « Go VTEC or Go Home!
 

·
Registered
Joined
·
472 Posts
This is some official info about the Acura Legend so this pretty much points out the systems way of working(for the legend):


TYPE II ENGINE. LEGEND SEDAN GS AND COUPE L AND LS
The Type II engine, introduced in the 1993Legend Coupe L and LS, is also
availablein the top-of-the-line Legend Sedan GS in 1994.It has the same 3206cc
displacement and 9.6:1compression ratio as the Type I engine of the Legend Sedan L
and LS. The Type II engine, however, produces 230 horsepower at 6200rpm and 206
lbs-ft of torque at 5000rpm. To achieve this higher power rating, a number of
refinements were made to increase intake and exhaust efficiency.In typical Acura
fashion, this power increase was achieved through refinement of the existing
operating systems, rather than by add-ons such as turbochargers, or by increasing
displacement and thus increasing weight.


VALVETRAIN
The cylinder heads are cast from the same alloy as the block. There are two
camshafts (one per cylinder bank), driven by a single toothed synthetic belt, and four
valves per cylinder.
The valvetrain incorporates a pent-roof combustion chamber and valves in a V
formation. Both exhaust and intake valves are actuated by a single rocker arm each,
and the hydraulic lash adjusters are set into the valve end of each rocker arm.

VALVE TIMING, LIFf AND DIAMETER (TYPE II ENGINE ONLY)
Valve timing of the Type II engine was altered to enhance high-end power above
5000 rpm while still maintaining ample low-end torque.
The intake valves open 5 degrees sooner and close 10degrees later, compared
to those of the Type I engine. The exhaust valves open 5 degrees sooner but close at
the same time as those of the Type I engine.
In addition, overall valve lift was increased. The intake valves open 10.2mm,
compared to 9.6mm in the Type I engine, and the exhaust valves open 9.5mm,
compared with 9.2mm in the Type I design. The intake valves of the Type II engine
are 34mm across, compared to 33mm in the Type I.


DIRECT IGNITIONSYSTEM
The platinum-tipped plugs are ignited by a new direct ignition system, similar to that
used in Formula One racing engines and in the NSX engine. Instead of the usual
single coil, there is an individual coil for each spark plug. A sensor mounted behind
one of the camshaft pulleys triggers the ignition.The system improves ignition
reliability, helping achieve 60,OOO-mile intervals between spark plug replacement.


DUAL KNOCKSENSORS
Incorporation of knock sensors, one for each cylinder bank, helped the engineers
program the ignition advance map closer to the optimum for fuel economy and
driveability. The sensors also allow the Legend engine to run safely (though with a
slight loss of power) should the tank be mistakenly filled with gasoline of octane
lower than the recommended premium unleaded fuel.


VARIABLE INDUCTION SYSTEM
A boost for both high-end power and low-end torque is provided by a Variable
Induction System, similar to that used in the NSX. A complex two-level intake
manifold -- made of aluminum to save weight -- provides three possible paths for air
being inducted into the engine. The path is selected by three butterfly valves that are
electronically controlled and actuated by intake vacuum. Up to 3200rpm, air for the
two banks of cylinders is strictly separated and is led through the longer of two intake
paths for optimum resonance charge effect at low engine speeds. At 3200rpm, the
two larger butterflies open and air flows through the shorter path for best resonance
effect in the midrange. Then at 3900rpm, the third butterfly opens to provide a large
plenum serving all cylinders. At this point the resonance effect is reduced, but an
inertia ram-tuning effect takes over to boost high-end breathing and power output.

PROGRAMMED FUEL INJECTION(PGM-FI)
The Legend engine is fueled by the PGM-FI sequential port fuel-injection system.
The system is controlled by microprocessor. On the basis of continuous
measurements of throttle angle, crankshaft angle, coolant temperature, intake air
temperature, manifold air pressure, ambient air pressure and exhaust oxygen content,
it meters fuel at the correct fuel-air ratio for the best balance of driveability, power,
fuel economy and exhaust emissions under each operating condition.
The entire system, including the fuel injectors, is designed specifically for the
Legend. The fuel-injection, ignition and induction systems are all controlled by the
engine's central 48K microprocessor.


Oh yeah and there are some other info here to pretty much point out what kind of system we've got in our Legends and especially type2 engine.

Now even though this is an advanced V-tec system(i-Vtec) you'll still get the idea about the difference in the v-tec and the legend engine.


2009 Acura TSX:

i-VTEC® VALVE CONTROL SYSTEM

The 2009 TSX's 2.4L engine features Acura's i-VTEC® "intelligent" valve control system. Featuring Variable Valve Timing and Lift Electronic Control (VTEC®) combined with Variable Timing Control™ (VTC™), the system provides power characteristics like those of a V6 without sacrificing the light weight or fuel efficiency of an inline four. A new VTEC® design uses three reduced-thickness aluminum rocker arms that operate a pair of intake and exhaust valves for each cylinder. At low rpm, the valves follow low-lift, short duration camshaft profiles to help boost low-end torque. Above 5000 rpm, the intake valves are operated by high-lift, long-duration camshaft profiles, for maximum high-rpm horsepower.

VTEC® lets the engine develop strong low-end torque along with exceptional high rpm power by varying valve lift and duration based on key engine parameters. To further refine powerplant operation, the TSX engine features the "intelligent" i-VTEC® system which adds Variable Timing Control™ (VTC™) to VTEC®. This provides continuously variable, computer controlled camshaft timing. In total, the TSX's i-VTEC® system provides performance, efficiency and emissions benefits by allowing the intake valve lift and valve timing to be continuously adjusted to suit the engine's operating parameters.

Variable Timing Control™ (VTC™)

The TSX's intake camshaft timing is continuously adjusted to suit engine operating conditions by a system called Variable Timing Control™ (VTC™). An integral part of the TSX's i-VTEC® system, the new TSX employs revised VTC™ parameters to enhance power output, fuel economy and emissions performance with its precise control of cam timing.

Camshaft position, intake manifold pressure and engine rpm are simultaneously monitored by the powertrain control unit (PCM), which then commands a VTC™ actuator to advance or retard the intake camshaft timing. The intake camshaft is almost fully retarded at idle to deliver a more stable idle and reduced hydrocarbon (HC) emissions. As engine RPM builds, the intake camshaft is progressively advanced so the intake valves open sooner and valve overlap increases. This reduces pumping losses, which increases fuel economy and further reduces exhaust emissions due to the creation of an internal exhaust-gas recirculation effect.

CYLINDER HEAD / VALVETRAIN
The TSX cylinder head is constructed of pressure-cast aluminum alloy and features four valves per cylinder actuated by dual overhead camshafts (DOHC). The cams are driven by an automatically adjusted silent-type chain. The chain system is maintenance free and runs in an oil bath for maximum durability. The combustion chambers have large "quench" areas to promote faster flame propagation and more complete burning, thus helping to reduce carbon monoxide (CO) and hydrocarbon (HC) exhaust emissions. Larger intake and exhaust valves and revised ports contribute to improved breathing. An increase in compression ratio from 10.5 to 11.0:1 is a significant contributor to the TSX's greater torque output.
 

·
The Infamous Left Lane
Joined
·
2,313 Posts
nicely said

^^^well put although for some reason i think we might be forget some other detail but your explaination gives a clear difference
 

·
Registered
Joined
·
93 Posts
ehh yea should have been more specific and noticed the tech lol and no the tec...first think that came to my mind was a 2000 accord coupe with the particle zero vtec motor. idkw lol.
 
1 - 10 of 10 Posts
Top