What is Vtec?
10-11-2006, 01:25 PM
#1
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What is Vtec?
this is a question that i have been curious for a long time, but what is Vtec? ive seen B16 engines, and B16 Vtecs, and so on. so what is the benfit with a Vtec Motor?
Marko
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10-11-2006, 08:30 PM
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Originally Posted by voltar
Just a variable valve timing system, originally produced for gas efficency. One of the most over-rated things the modern auto industry. god damn ricers...
10-11-2006, 08:56 PM
#6
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its actually magic; voodoo in fact... it gives honda's powers 
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k, so the engine operates normally, but at a certain rpm, (i.e. 6500), when vtec comes in to play, it changes the cam profile to more aggressive cams and leaves the intake and exhaust valves open longer, compared to in normal mode
\k, so the engine operates normally, but at a certain rpm, (i.e. 6500), when vtec comes in to play, it changes the cam profile to more aggressive cams and leaves the intake and exhaust valves open longer, compared to in normal mode
10-12-2006, 02:28 PM
#12
Haha too funny...more aggressive cams dont have the same effect as vtec. Vtec allows you to have a lower cam angle at low rpm, to give you as much bottom end torque as possible and maintain fuel efficiency but then changes to a larger cam angle at high rpm to let more airflow through the engine, make more hp, and burn all your gas
. Vtec also changes ignition timing when it engages to rev, higher, quicker, etc. If you just ran an aggressive cam you would have a horrible idle, and poor off idle acceleration.
BTW do any v8's have variable valve timing? cause that would be INSANE!
. Vtec also changes ignition timing when it engages to rev, higher, quicker, etc. If you just ran an aggressive cam you would have a horrible idle, and poor off idle acceleration.BTW do any v8's have variable valve timing? cause that would be INSANE!
10-12-2006, 03:04 PM
#13
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HONNNN DAAAAA
The new 5.4-liter Triton V-8 engine that powers Ford's F-150 is designed with three valves per cylinder, variable-cam timing, and a host of other features that provide increased power along with improved refinement and fuel efficiency.
The new 24-valve engine will be our first modular V-8 to use variable-cam timing. This design allows Ford engineers to optimize intake-and exhaust-valve actuation across the rev range. It represents the industry's first mass application of dual-equal variable-cam timing, which shifts the intake and exhaust valve timing together.
Ford Motor Company's new Triton V-8
In combination with precise control of spark timing, fuel injection, and use of electrically controlled Charge Motion Control Valves in the intake ports, this technology produces class-leading power and torque, particularly at the lower engine speeds that are so important to applications such as towing and heavy hauling.
Variable-Cam Timing Offers Multiple Benefits
Our new three-valve cylinder head uses a single overhead camshaft for each bank of cylinders. The cams press down on roller-finger cam followers to open the intake and exhaust valves, which are closed by coil springs as in all Ford's V-8 engines.
Conventional camshafts are permanently synchronized with the engine's crankshaft so that they operate the valves at a specific point in each combustion cycle. In our modular two-valve 5.4-liter V-8 engine, the intake valve opens slightly before the piston reaches the top of the cylinder and closes about 60 degrees after the piston reaches the bottom of the stroke on every cycle, no matter what the engine speed or load is.
Variable-cam timing allows the valves to be operated at different points in the combustion cycle, to provide performance that is precisely tailored to the engine's specific speed and load at that moment. The timing is set to allow the best overall performance across the engine's normal operating range.
If conditions require earlier valve opening and closing, for example to achieve more low speed torque, the Powertrain Control Module commands solenoids to alter oil flow within the hydraulic cam timing mechanism, which rotates the camshafts slightly. If the valves should open later, to generate more high-speed power, the mechanism retards the cams as needed.
The result is enhanced efficiency under low-load conditions, such as at idle or highway cruising, and increased power for brisk acceleration or times of high demand.
The ability to control valve timing as well as spark timing allowed Ford engineers to design a combustion chamber with a higher compression level than in the two-valve V-8 engines while still using regular gasoline octane levels. Higher compression ratio produces greater efficiency, delivering more power and improved combustion efficiency.
The new 5.4-liter Triton V-8 engine that powers Ford's F-150 is designed with three valves per cylinder, variable-cam timing, and a host of other features that provide increased power along with improved refinement and fuel efficiency.
The new 24-valve engine will be our first modular V-8 to use variable-cam timing. This design allows Ford engineers to optimize intake-and exhaust-valve actuation across the rev range. It represents the industry's first mass application of dual-equal variable-cam timing, which shifts the intake and exhaust valve timing together.
Ford Motor Company's new Triton V-8
In combination with precise control of spark timing, fuel injection, and use of electrically controlled Charge Motion Control Valves in the intake ports, this technology produces class-leading power and torque, particularly at the lower engine speeds that are so important to applications such as towing and heavy hauling.
Variable-Cam Timing Offers Multiple Benefits
Our new three-valve cylinder head uses a single overhead camshaft for each bank of cylinders. The cams press down on roller-finger cam followers to open the intake and exhaust valves, which are closed by coil springs as in all Ford's V-8 engines.
Conventional camshafts are permanently synchronized with the engine's crankshaft so that they operate the valves at a specific point in each combustion cycle. In our modular two-valve 5.4-liter V-8 engine, the intake valve opens slightly before the piston reaches the top of the cylinder and closes about 60 degrees after the piston reaches the bottom of the stroke on every cycle, no matter what the engine speed or load is.
Variable-cam timing allows the valves to be operated at different points in the combustion cycle, to provide performance that is precisely tailored to the engine's specific speed and load at that moment. The timing is set to allow the best overall performance across the engine's normal operating range.
If conditions require earlier valve opening and closing, for example to achieve more low speed torque, the Powertrain Control Module commands solenoids to alter oil flow within the hydraulic cam timing mechanism, which rotates the camshafts slightly. If the valves should open later, to generate more high-speed power, the mechanism retards the cams as needed.
The result is enhanced efficiency under low-load conditions, such as at idle or highway cruising, and increased power for brisk acceleration or times of high demand.
The ability to control valve timing as well as spark timing allowed Ford engineers to design a combustion chamber with a higher compression level than in the two-valve V-8 engines while still using regular gasoline octane levels. Higher compression ratio produces greater efficiency, delivering more power and improved combustion efficiency.
Last edited by raven89camaro; 10-12-2006 at 03:11 PM. Reason: Automerged Doublepost
10-12-2006, 03:18 PM
#14
vtec....variable valve timing and electronic lift control
This allows good gas mileage and max power. The non vtec (primary and secondary lobes) are designed for good power/torque while maintaining relatively low engine noise and gas consumption. Then when vtec engages, the vtec solenoid uses oil pressure to move the pins that lock the all 3 rocker arms together and allow the rockers to follow the 1 vtec lobe and operate both valves for maximum power/tq at higher rpms.
I'm sorry, but anyone that thinks vtec is ghey and over rated is prolly just jealous that their POS gets smoked by little 1.6L and 1.8L hondas.
Vtec is quite an ingenious design, and that must be why all of the other car manufacturers (like ford, toyota, nissan) have a variable valve timing design of their own....over rated eh?
Honda b-series vtec cylinder heads are well designed, and make amazing power (even in stock form), especially if you add a turbo. There's no real need to port and polish vtec heads, unless you plan on staying n/a where every little thing counts.
This allows good gas mileage and max power. The non vtec (primary and secondary lobes) are designed for good power/torque while maintaining relatively low engine noise and gas consumption. Then when vtec engages, the vtec solenoid uses oil pressure to move the pins that lock the all 3 rocker arms together and allow the rockers to follow the 1 vtec lobe and operate both valves for maximum power/tq at higher rpms.
I'm sorry, but anyone that thinks vtec is ghey and over rated is prolly just jealous that their POS gets smoked by little 1.6L and 1.8L hondas.
Vtec is quite an ingenious design, and that must be why all of the other car manufacturers (like ford, toyota, nissan) have a variable valve timing design of their own....over rated eh?
Honda b-series vtec cylinder heads are well designed, and make amazing power (even in stock form), especially if you add a turbo. There's no real need to port and polish vtec heads, unless you plan on staying n/a where every little thing counts.
10-12-2006, 04:44 PM
#15
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Oh yes quite a few V8s have VVT. GM has had VVT for a while in NorthStars 4.6s, the GenIV small blocks, even the Toyota Tundra has VVT...
And before people get overexcited remember that Honda didn't invent the concept.
And before people get overexcited remember that Honda didn't invent the concept.