Nissan's CVTS
Strider Negro
08-10-2003, 03:35 PM
like the title says, what the hell is it and how does it differ from vtec or vvti.
i know it's a dumb question but i just wanted to keep informed.
i know it's a dumb question but i just wanted to keep informed.
454Casull
08-11-2003, 04:08 PM
If you mean CVTs, they're transmissions.
rsxer45
08-11-2003, 09:45 PM
I think he means CVTC (Continously Variable Valve Timing Control) which is similar to V-TEC. Read the sticky post at the top of the Engineering/Technical Forum for info on how V-TEC works.
Neutrino
08-11-2003, 10:29 PM
its not that similar to vtec.....
vtec changes both the lift of the valves and the timing
the CVTS just alters the timing
vtec changes both the lift of the valves and the timing
the CVTS just alters the timing
rsxer45
08-11-2003, 10:54 PM
Originally posted by Neutrino
its not that similar to vtec.....
vtec changes both the lift of the valves and the timing
the CVTS just alters the timing
yeah you are right. Sorry for the mistake. I always thought they operated in a similar fashion, but I guess it was ignorance on my part. Here some info I found:
"Q: Does the CVTC motor in the Spec-V work the same as the VTEC motors in Hondas? If they do, then is it possible to use a VTEC controller in a Spec-V?
Sarah: No, due to the continuously changing cam profile, CVTC cannot be controlled like VTEC. It is a continuous variable adjustment unlike VTEC which is either on or off. CVTC improves overall engine performance by supplying Constant Valve Timing Control through all operating conditions. The crankshaft position, camshaft position, engine speed, and engine coolant temperature input signals are sent to the ECU. The ECU sends a variable duty cycle to a pulse width modulated solenoid that works like an injector. By adjusting and directing the amount of oil pumped into the CVTC's chambers and allowed to drain back into the engine, the ECU controls the retard or advance of the cam up to 30 crank degrees (vs. 14 degrees on the older VTC motors). The cam is retarded at idle to create a smoother idle and decrease emissions, advanced in the mid range to increase breathing, and retarded at high rpm to increase peak horsepower and fuel efficiency. VTEC is like having a stock cam at low rpm and a race cam at high rpm. At high rpm, the VTEC solenoid opens to allow oil from the oil pump to flow to a piston in the rocker arm. This piston engages a lost motion rocker in an extra intake cam, locking it to the two rockers that control both intake valves. The intake valve on this second cam profile remains open longer which increases breathing. A VTEC controller interprets the MAP sensor signal, throttle position and rpm to activate the VTEC solenoid at the user's specified rpm. It can also add fuel by intercepting the MAP sensor signal and tricking the ECU into thinking the engine is flowing more air. The SR20VE has a more similar system to VTEC."
http://www.nissanperformancemag.com/december02/ask_sarah/
its not that similar to vtec.....
vtec changes both the lift of the valves and the timing
the CVTS just alters the timing
yeah you are right. Sorry for the mistake. I always thought they operated in a similar fashion, but I guess it was ignorance on my part. Here some info I found:
"Q: Does the CVTC motor in the Spec-V work the same as the VTEC motors in Hondas? If they do, then is it possible to use a VTEC controller in a Spec-V?
Sarah: No, due to the continuously changing cam profile, CVTC cannot be controlled like VTEC. It is a continuous variable adjustment unlike VTEC which is either on or off. CVTC improves overall engine performance by supplying Constant Valve Timing Control through all operating conditions. The crankshaft position, camshaft position, engine speed, and engine coolant temperature input signals are sent to the ECU. The ECU sends a variable duty cycle to a pulse width modulated solenoid that works like an injector. By adjusting and directing the amount of oil pumped into the CVTC's chambers and allowed to drain back into the engine, the ECU controls the retard or advance of the cam up to 30 crank degrees (vs. 14 degrees on the older VTC motors). The cam is retarded at idle to create a smoother idle and decrease emissions, advanced in the mid range to increase breathing, and retarded at high rpm to increase peak horsepower and fuel efficiency. VTEC is like having a stock cam at low rpm and a race cam at high rpm. At high rpm, the VTEC solenoid opens to allow oil from the oil pump to flow to a piston in the rocker arm. This piston engages a lost motion rocker in an extra intake cam, locking it to the two rockers that control both intake valves. The intake valve on this second cam profile remains open longer which increases breathing. A VTEC controller interprets the MAP sensor signal, throttle position and rpm to activate the VTEC solenoid at the user's specified rpm. It can also add fuel by intercepting the MAP sensor signal and tricking the ECU into thinking the engine is flowing more air. The SR20VE has a more similar system to VTEC."
http://www.nissanperformancemag.com/december02/ask_sarah/
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