Nissan 370Z Forum - View Single Post

XwChriswX · 10-28-2012, 05:25 PM

Quote:

Originally Posted by gabe3d

Didn't know that Toyota had something to VVEL, but after some research it's called Valvematic. However it doesn't seem like any of the Toyotas in the US has this.

VVT-I is like nissan's VTC

I think VVT-I is more like VVEL...

Quote:

Automakers have addressed this concern with something called "variable valve timing" (VVT). The Toyota Tundra's i-Force 5.7L V8, Toyota's newest VVT-i engine, has the ability to vary the timing of the valves in relation to engine speed. It does this by using engine oil pressure to move the camshaft slightly, so that more aggressive lobe designs are used when the engine is running at a higher rpm. By doing this, the i-Force V8 is able to run a camshaft profile that provides good fuel efficiency in every day driving, but is still able to churn out gobs of power when the pedal is pressed to the floor.

The dual VVT-i in the Tundra takes things a step further by allowing the exhaust and intake valves to open at the same time at very high RPMs in order to scavenge the airflow as much as possible. This all adds up to a V8 engine that produces 381 horsepower at 5600 rpm while still generating 401 lb-ft of torque at as low as 3600 rpm. Not only that, but in the 2 wheel drive models, the Tundra gets a respectable 20 miles per gallon on the highway. Perhaps most importantly, Toyota's variable valve timing system lets you have killer horsepower without getting killed at the gas pump.