# Vvt?



## SilverSentra99 (Oct 23, 2002)

Dose the sentra have Variable Valve timing at all, like Vtec hondas and if we do what is the difference between the two, seems like i read that we do somewhere, I have a 99 B14 sentra. THanks.


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## onyxeros (Jul 26, 2002)

i believe you have variable timing but not like vtec. on your car it's electrical.

O


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## zeno (Sep 17, 2002)

Currently there are no U.S. Nissans w/ the true VVT engine. The Spec-V has a similar setup known as the CVTC. I really don't have the info. on it but NPM has info. on it.Ask Sarah - CVTC 

Variable valve timing engines all pretty much work on the same principles but I'm sure people can argue VVT vs. VTEC (something I'm not knowledgable enough to do). There has been a lot of discussion going around the boards concerning swapping in an sr20VE engine (the VVT engine) into their Sentra/200SXs. IMO, if you are willing to go through the expenses and pain in the ass of swapping engines you might as well go forced induction w/ the sr20det. sr20deforum has a good write-up on it sr20ve info and NPM has a write up on the swap sr20ve swap . Hope this helps.


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## Guest (May 1, 2003)

Your first statement is not true.
Yes, the 2.5L has infinitely variable valve timing... just like Honda.


*Currently there are no U.S. Nissans w/ the true VVT engine. The Spec-V has a similar setup known as the CVTC. I really don't have the info. *


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## zeno (Sep 17, 2002)

What do you mean I'm incorrect? This is the answer straight from Nissan Performance Mag.
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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.


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## Guest (May 1, 2003)

I stand corrected...
OK, I was under the impression that Honda had infinitely variable cam position system. Never had a Honda so wasn't sure. So Nissan has a superior system to Honda's. Even now Honda has no equivalent?


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## zeno (Sep 17, 2002)

Well at least people have the option of getting VTEC in the U.S. while Nissan has its head up its ass and keeps giving us wussified versions of what the rest of the world gets.

Skyline, Silvia, sr20det motors, sr20ve motors, GTi-Rs, etc., etc.


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## Guest (May 9, 2003)

I gather then that you think that VTEC is superior to CVTC?



zeno said:


> *Well at least people have the option of getting VTEC in the U.S. while Nissan has its head up its ass and keeps giving us wussified versions of what the rest of the world gets.
> *


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## zeno (Sep 17, 2002)

Not at all, it just pisses me off that Nissan doesn't release technology that is available in the rest of the world. I definitely think Nissan technology is superior to Honda but none of it reaches the U.S. shores. Unfortunately, I think Honda in a lot of ways has the upper hand in the U.S.

Another thing, Honda has yet to discover the wonderful usefulness of torque.


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## landlord (Jun 11, 2002)

vtec control duration and lift of the valve (opening them a little farther and a little longer). vtc just controls what time they open (sooner or later), but the lift and duration remain the same. vtec is better.


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## landlord (Jun 11, 2002)

ok should have read the whole thred my bad stating info thats already stated.,


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## niky (Jul 20, 2002)

actually, nissan has a pretty sh*tty rep anywhere BUT japan and the US. I don't know anywhere else you can get an SR20VE. Most asian markets don't even get straight nissan, but rebuilds by companies like Yulon (taiwan) and... get this... Samsung.

Since the Spec V is, as yet, still an american market baby, most other countries don't get CVTC... while you could probably find a VTEC honda anywhere from Maine to Timbuktu.

consider yourself lucky, comrade yankee.


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