x yah la nk laju sgt pon..nk pegi ke destinasi yg dtuju sampai jugak cume mase je.
Monday, December 27, 2010
CHERVOLET CAMARO 1968
Thursday, October 21, 2010
MIVEC (Mitsubishi Innovative Valve timing Electronic Control system)
MIVEC (Mitsubishi Innovative Valve timing Electronic Control system)[1] is the brand name of a variable valve timing (VVT) engine technology developed by Mitsubishi Motors. MIVEC, as with other similar systems, varies the timing of the intake and exhaust camshafts which increases the power and torque output over a broad engine speed range while also being able to help spool a turbocharger more quickly.
MIVEC was first introduced in 1992 in their 4G92 powerplant, a 1,597 cc naturally aspirated DOHC 16 valve straight-4.[2] At the time, the first generation of the system was named Mitsubishi Innovative Valve timing and lift Electronic Control.[3] The first cars to use this were the Mitsubishi Mirage hatchback and the Mitsubishi Lancer sedan. While the conventional 4G92 engine provided 145 PS (107 kW; 143 hp) at 7000 rpm,[4] the MIVEC-equipped engine could achieve 175 PS (129 kW; 173 hp) at 7500 rpm.[5] Similar improvements were seen when the technology was applied to the 1994 Mitsubishi FTO, whose top-spec GPX variant had a 6A12 1997 cc DOHC 24 valve V6 with peak power of 200 PS (147 kW; 197 hp) at 7500 rpm.[6] The GR model, whose otherwise identical powerplant was not MIVEC-equipped, produced 180 PS (132 kW; 178 hp) at 7000 rpm by comparison.[7]
Although initially designed to enhance performance, the system has subsequently been developed to improve economy and emissions, and has been introduced across Mitsubishi's range of vehicles, from the i kei car to the high-performance Lancer Evolution sedan.
Newest developments have led to MIVEC system being evolved into a continuous variable valve timing and also being the first VVT system to be used into a passenger car diesel engine.
Operation
Some types of variable valve control systems optimize power and torque by varying valve opening times and/or duration. Some of these valve control systems optimize performance at low and mid-range engine speeds. Others focus on enhancing only high-rpm power. MIVEC system provides both of these benefits by controlling valve timing and lift. The basic operation of the MIVEC system is altering the cam profiles and thus tailoring engine performance in response to driver input.[8]In essence, MIVEC serves the same function as "swapping cams", something that car racers might do when modifying older-design engines to produce more power. However, such swaps come with a compromise - generally yielding either greater low-end torque or more high-end horsepower, but not both. MIVEC achieves both goals. With MIVEC, the "cam swap" occurs automatically at a fixed engine speed. The cam switch operation is transparent to the driver, who is simply rewarded with a smooth flow of power.[8]
Two distinct cam profiles are used to provide two engine modes: a low-speed mode, consisting of low-lift cam profiles; and a high-speed mode. The low-lift cams and rocker arms - which drive separate intake valves - are positioned on either side of a centrally located high-lift cam. Each of the intake valves is operated by a low-lift cam and rocker arm, while placing a T-lever between them allows the valves to follow the action of the high-lift cam.[8]
At low speeds, The T-lever's wing section floats freely, enabling the low-lift cams to operate the valves. The intake rocker arms contain internal pistons, which are retained by springs in a lowered position while the engine speed is below the MIVEC switchover point, to avoid contacting the high-lift T-shaped levers. At high speeds, hydraulic pressure elevates the hydraulic pistons, causing the T-lever to push against the rocker arm, which in turn makes the high-lift cam operate the valves.[8]
In summary, MIVEC switches to the higher cam profile as engine speed increases, and drops back to the lower cam profile as engine speed decreases. The reduced valve overlap in low-speed mode provides stable idling, while accelerated timing of the intake valve's closing reduces backflow to improve volumetric efficiency, which helps increase engine output as well as reduce lift friction. High-speed mode takes advantage of the pulsating intake effect created by the mode's high lift and retarded timing of intake valve closure. The resulting reduced pumping loss of the larger valve overlap yields higher power output and a reduction in friction. The low- and high-speed modes overlap for a brief period, boosting torque.[8]
From the 4B1 engine family onward, MIVEC has evolved into a continuous variable valve timing (CVVT) system (dual VVT on intake and exhaust valves).[9] Many older implementations only vary the valve timing (the amount of time per engine revolution that the intake port is open) and not the lift. Timing is continuously independently controlled to provide four optimized engine-operating modes:[9]
- Under most conditions, to ensure highest fuel efficiency, valve overlap is increased to reduce pumping losses. The exhaust valve opening timing is retarded for higher expansion ratio, enhancing fuel economy.
- When maximum power is demanded (high engine speed and load), intake valve closing timing is retarded to synchronize the intake air pulsations for larger air volume.
- Under low-speed, high load, MIVEC ensures optimal torque delivery with the intake valve closing timing advanced to ensure sufficient air volume. At the same time, the exhaust valve opening timing is retarded to provide a higher expansion ratio and improved efficiency.
- At idle, valve overlap is eliminated to stabilize combustion.
MIVEC-MD
In the early years of developing its MIVEC technology, Mitsubishi also introduced a variant dubbed MIVEC-MD (Modulated Displacement),[11][3] a form of variable displacement. Under a light throttle load, the intake and exhaust valves in two of the cylinders would remain closed, and the reduced pumping losses gave a claimed 10–20 percent improvement in fuel economy. Modulated Displacement was dropped around 1996.[11]
he Honda Civic Type R is the highest performance version of the Honda Civic made by Honda Motor Company of Japan. The Type R designation is given to models that have been specially developed and tuned in house for the sole purpose of circuit competition and as a high performance vehicle from Honda's stables. Its lineage can be traced directly to the 1992 Honda NSX Type R, featuring a lightened and stiffened body, specially fine tuned engine and upgraded brakes and chassis. Other characteristics are the use of the special colour from the days of Honda's successful F1 winning car from the 60's called "Championship White" and a Honda emblem with a red background. Red is also used in the interior to give it a special sporting distinction and to separate it from other Honda models. In Japan, a one-make series of Honda Type R cars where privateers can purchase a off-road Type R and compete in a series championship is a stepping stone for many aspiring racing drivers. The Type R has helped to increase Honda's overall image in racing as well as in the sports car consumer market.
Tuesday, October 19, 2010
4AGE 20V Blacktop Engine Swap
4AGE 20V Blacktop Engine Swap
The AE86 was available with a fuel-injected 4-cylinder twin-cam 1587 cc 4A-GEU engine in Japan and Europe which was also used in the first-generation Toyota MR2 (AW11). This engine had a maximum power output of 130 PS (97 kW) and 103 ft·lbf (140 Nm) of torque in standard form.[1] The AE86 came with a 5-speed manual gearbox, and later came with the option of an automatic. The 4A-GE engines used in the AE86 and AW11 were equipped with T-VIS (Toyota Variable Induction System). The AE86 had an optional Limited Slip Differential (LSD).[1]
In North America, a modified 4A-GEC engine was used to comply withCalifornia emissions regulations. Power was rated at 112 bhp (84 kW), and 100 ft·lbf (136 Nm) of torque.[1]
The AE86 used ventilated disc brakes. The car was equipped with a MacPherson strut style independentsuspension at the front and a four-link live axle with coil springs for the rear. Stabilizer bars were present at both ends.[1]
Lower-spec American AE86 SR5 models used the 1587 cc 4A-C SOHC unit, did not have an optional LSD, and had rear drum brakes.
Models equipped with the 4A-GE engine received a 6.7" rear differential, while 3A-U, 4A-U, and 4A-C models received a smaller, weaker, 6.38" rear differential.
The AE86 SR5 (4A-C equipped) had an optional automatic transmission, though the GT-S model (with the 4A-GE DOHC engine) only came with a standard 5-speed manual gearbox.
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