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VTEC ( Variable Valve Timing and Lift Electronic Control ) is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine.
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VTEC and Variable
The VTEC engine used Variable Valve Timing to provide increased power in the high rev range, while still allowing low fuel consumption and better idling at low RPMs.
It was equipped with a mid-engine, rear-wheel drive layout, powered by an all-aluminium V6 gasoline ( petrol ) engine featuring Honda's Variable Valve Timing and Lift Electronic Control ( VTEC ) system.
It is a 3. 5 L ( 3471 cc ) SOHC V6 with VTEC Variable Valve Timing and is made by Honda in Anna, Ohio.
They were made in 1. 6 -, 1. 7 -, 1. 8 -, and 2. 0-liter variants, with and without VTEC ( Variable Valve Timing and Electronic Lift Control ).
VTEC and Valve
* Valve Configuration: SOHC, 16 valves, VTEC
* Configuration Valve: SOHC, 16 valves, VTEC
* Valve Configuration: SOHC, 16 valves ( 4 valves per cylinder ), VTEC
* Valve Configuration: SOHC, 16 valves, VTEC
* Valve Configuration: SOHC, 16 valves, VTEC
* Valve train: four-cylinder, DOHC VTEC, 16-valve
VTEC and is
: Honda's VTEC technology is introduced in the NSX
This is the most important generation of models in Honda's history as this is where the manual for the DA6 states, the first VTEC engine in the world is a B16A and was used in an Integra RSi / XSi which bore the chassis 1100001.
VTEC engagement is at 4800 rpm on the B16A engine, redline for the XSi is 8200 rpm.
It is powered by a 270 hp ( 201 kW ); later revised to, based on the new SAE measurement standard for horsepower and of torque, 3. 2 L 24 valve SOHC VTEC V6 engine mated to either a 5-speed automatic with SportShift or 6-speed manual.
The VTEC cylinder idling system of the engine closes the valves in three of the four cylinders when the car is decelerating, reduces the power lost to the engine by 50 percent and allows the IMA to extract more electrical energy during braking.
A third option is to change the cam timing profile, of which Honda VTEC was the first successful commercial design for altering the profile in real-time.
This is because VTEC requires a third center rocker arm and cam lobe ( for each intake and exhaust side ), and, in the SOHC engine, the spark plugs are situated between the two exhaust rocker arms, leaving no room for the VTEC rocker arm.
The earliest VTEC-E implementation is a variation of SOHC VTEC which is used to increase combustion efficiency at low RPM while maintaining the mid range performance of non-vtec engines.
VTEC-E is the first version of VTEC to employ the use of roller rocker arms and because of that, it forgoes the need for having 3 intake lobes for actuating the two valves -- two identical lobes for non-VTEC operation and one lobe for VTEC operation.
Because of this, at low RPM, when VTEC is not engaged, one of the two intake valves is allowed to open only a very small amount due to the mild cam lobe, forcing most of the intake charge through the other open intake valve with the normal cam lobe.
When in VTEC, since the " normal " cam lobe has the same timing and lift as the intake cam lobes of the SOHC non-VTEC engines, both engines have identical performance in the upper powerband assuming everything else is the same.
With the later VTEC-E implementations, the only difference it has with the earlier VTEC-E is that the second " normal " cam profile has been replaced with a " wild " cam profile which is identical to the original VTEC " wild " cam profile.
3-Stage VTEC is a version that employs 3 different cam profiles to control intake valve timing and lift.
The performance i-VTEC system is basically the same as the DOHC VTEC system of the B16A's ; both intake and exhaust have 3 cam lobes per cylinder.
Performance i-VTEC is a combination of conventional DOHC VTEC with VTC.
The economy i-VTEC is more like the SOHC VTEC-E in that the intake cam has only two lobes, one very small and one larger, as well as no VTEC on the exhaust cam.
VTEC and system
The VFR800 was the first to utilize Honda's VTEC system, as well as the first Honda motorcycle to feature ABS and a linked braking system.
The seventh generation VFR1200 has since replaced the original VTEC variable valve timing system with the unicam system originally developed for the CRF450R dirt bike.
The new engine also adopted a VTEC system which operates only two valves per cylinder below 6, 800 resulting in improved torque, fuel economy and emissions compared to non-VTEC engines.
The 1996 – 2004 3. 5RL's engine was the last in the Honda and Acura lineup not to use Honda's variable valve timing system ( VTEC ), along with the seventh generation Honda Civic DX and LX non-VTEC engines.
The VTEC system uses two camshaft profiles and hydraulically selects between profiles.
The VTEC system provides the engine with multiple camshaft profiles optimized for both low and high RPM operations.
VTEC, the original Honda variable valve control system, originated from REV ( Revolution-modulated valve control ) introduced on the CBR400 in 1983 known as HYPER VTEC.
The US market saw the first VTEC system with the introduction of the 1991 Honda NSX, which used a 3-litre DOHC VTEC V6 with.
As popularity and marketing value of the VTEC system grew, Honda applied the system to SOHC ( Single Over Head Cam ) engines, which share a common camshaft for both intake and exhaust valves.
Other notable features included an independent, 4-channel anti-lock brake system ; titanium connecting rods in the engine to permit reliable high-rpm operation ; an electric power steering system ; Honda's proprietary VTEC variable valve timing system ( a first in the US ) and, in 1995, the first electronic throttle control fitted to a Honda.
The next step was taken in 1989 by Honda with the VTEC system.
The VTEC system was also further developed to provide other functions in engines designed primarily for low fuel consumption.
VTEC can be considered the first " cam switching " system and is also one of only a few currently in production.
VTEC and by
Often they are referred to by their toxin producing capabilities, verocytotoxin producing E. coli ( VTEC ) or Shiga-like toxin producing E. coli ( STEC ).
This top ranked DOHC VTEC model was complemented by more docile models that used dual-carburator or PGM-Fi versions of the versatile ZC engine but in the more compact SOHC configuration.
Additionally, the center lobe on the camshaft cannot be utilized by both the intake and the exhaust, limiting the VTEC feature to one side.
The difficulty of incorporating VTEC for both the intake and exhaust valves in a SOHC engine has been removed on the J37A4 by a novel design of the intake rocker arm.
In 1991 the Acura NSX powered by the C30A became the first VTEC equipped vehicle available in the US.
** VTEC — Varies duration, timing and lift by switching between two different sets of cam lobes.
In later iterations, it supersedes the earlier VTEC-E and VTEC designs by combining the fuel economy and low RPM benefits with the high RPM power of the original SOHC VTEC design.
** AVLS — Varies duration, timing and lift by switching between two different sets of cam lobes ( similar to Honda VTEC ).
By 2001 a model powered by Honda's 1. 5 L VTEC engines ( VTi ) appeared, featuring a rear-stabilizer for better handling.
Like the first-generation MDX, the Pilot propelled by an aluminum alloy 3. 5 L SOHC, 24-valve VTEC V6 engine with timing belt driven camshafts.
The heads are a twenty-four valve, dual-overhead cam ( DOHC ) design and contain the VTEC mechanism, which is actuated by oil pressure.
This was the only DOHC VTEC V6 ever built by Honda for longitudinal applications and was only used in one non-production car, the Honda FS-X concept.
The implementation of VTEC was seen as a bid by Honda to meet tightening noise and emissions standards in Japan and abroad while improving the peak horsepower of the engine.
The engine is improved by Honda's VTEC technology in later models.
0.202 seconds.