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The following information on Toyota's Variable Valve Timing and Lift (with intelligence) system is derived in large from the October issues of Sport Compact Car and Car and Driver. As always, I encourage you to obtain a copy for yourself.The VVT-i portion of the system continuously varies intake valve timing throughout the rev range by hydraulically rotating the camshaft relative to its drive gear. Note that VVT (without the "i") did not do this continuously. The VVL portion of the system is similar to Honda's VTEC system, incorporating two distinct cam profiles. However, the actual mechanism is quite different. Both cam lobes operate a single wide rocker arm that acts on both intake or both exhaust valves. A needle-bearing roller on the arm follows the low-rpm, short-duration, low-lift lobe, forcing both valves to open and close on that profile. The roller design and roller bearings on the rocker arm pivot help to minimize valvetrain friction. The high-rpm, higher-duration, longer-lift lobe rubs on a hardened steel slipper follower mounted to the rocker arm with a spring. Even though the high-rpm lobe is pushing down further than the low-rpm lobe, the spring absorbs the extra movement. At 6000rpm, the ECU sends a signal to an oil control valve at the end of the camshaft that puts oil pressure behind a lock pin in the rocker arm, sliding the pin under the spring-loaded slipper follower, locking it to the rocker arm and forcing the arm to follow the high-rpm cam profile. What's VVT-i and VVTL-i???That has been a question a lot of people have been asking lately. What is VVT-i and VVTL-i and what do they do and why are so many people talking about it. Well VVT-i is Variable Valve Timing - with intelligence and VVTL-i is Variable Valve Timing & Lift with intelligence. So we got that out of the way what do they both do to my motor???Well lets explain VVT-i that's in the Toyota Celica GT's first. Variable Valve Timing with intelligence is quite remarkable in it operation and what it does. Most cars run on valve timing that is set and cannot be changed unless you buy a set of aftermarket cam gears. Which this method is quite pricey but can give you better performance usually at the cost of fuel economy and usually makes your low-end power suffer to make the top end of your power band better. This sometimes hurts drivability. So you can see for buying adjustable cam gears it can do well at the track but you might have a hard time driving around at 30 miles per hour.Enough about that. VVT-i is a tuners best friend as it tunes your car as you drive. Always adjusting your valve timing but the way of spring loaded cam gears that can change in a heartbeat at the computers wishes. The new VVT-I motors also have a computer controlled ignition system that changes ignition timing in a moments notice along with the variable valve timing. So when your cruising along on the highway or downtown and your not looking to rip up the asphalt the computer senses that, adjusts the valves and ignition to make the motor use less fuel. When your looking to get from 0-FAST as soon as possible and you mash the throttle the computer senses the throttle wide open and reads the sensors on the motor to determine the best positions for your valves and ignition timing to give you the most power!! And its constantly changing while you drive. Even after you take off and switching through the gear the computer is still working on the best timing for that rpm and throttle position as well as other factors to get you going fast! So as you can see this isn't your ordinary computer. This thing actually thinks about doing what's best for your motor. How to save the most gas when you're on that trip or how to make the most ponies when you're at the track this computer is on our side!!!Now if you got that digested and feel confident about your VVT-i knowledge then we are going to give you a shot of "roids" in your arm to let you feel how the VVTL-i feels when you hammer on this engine. The VVTL-i engine in the new Celica GT-S is ready to throw you back in your seat and take you for a serious ride. The VVTL-i motors use all the same technology that was mentioned about the VVT-i motors but adds a twist to the deal. It not only changing valve and ignition timing on the fly, it also has a second set of cam profiles on each cam to give you the "race car when you want" it approach. Tach it up to 6 grand and the motor turns into a monster. The motor puts out a scream as it warps into hyper drive! It feels like a race turbo kicking in with all the added horsepower and torque in a matter of a few hundred rpms. If you think it put you in your spot when you launch from a stop wait till you hit 6!!! This isn't a slightly noticeable change either. It's a "WOW I'm moving!" That's were you get the "L" or Lift for the VVTL-i, the second set of cam profiles adds more lift to the valves and increases power dramatically I might add! It uses oil pressure to push a pin under the rocker arms and cams to force the motor to use the bigger profiles that are not used under normal driving.