I was wondering if anyone could explain nissan's version of variable valve timing. does it work like V-tec or os more similar to porsche and bmw's version. I thougt I read that the nissan cams don't effect the system. That there is not extra lobes on the cams like vtec, vannos and vario-cam. Could someone please lend some knowledge.
well nobody seems to be taking a stab at this, so ill put in my uninformed 2 cents.
The only variable that changes through the rev range is the butterfly vavles open up on the intake, allow more air in after 5500rpm i think. Im not sure.
VVT..Hmm I always thought it was VTC. Anyway, while I am not sure which engine you are talking about I will use the GA's system as an example.
The GA is a DOHC motor. One cam for intake valves and one cam for exhuast valves. What the system does is change the timming between the two. You mave have heard of the term "overlap" when talking about cams. This systems varies the overlap. I guess the idea is for low emmisions while crusing and higher power when you are up in the RPM range. One member posted that the timming change happens at 1500RPM and back again at 5500RPM. IIRC V-tec does the timming thing, plus it has an extra set of lobes that give increased valve lift as well. Nissan has a system like this. Its called VVL and is used on motors like the SR20VE and SR16VE. 98sr20ve has one in his car.
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Patrick Scott
Yeah, thats a roll cage in there.
I shall call him...Mini-Me
okay, so on the SR20 motor, you are saying that there is another set of cam lobes. similar to v-tec ?. I am very familiar with V-TEC, I am just trying to find out how Nissan's version (on the SR20 [s14]) differs, or relates to it.
Originally posted by PatScottAKA99XE VVT..Hmm I always thought it was VTC. Anyway, while I am not sure which engine you are talking about I will use the GA's system as an example.
i think he is reffering to an engine nissan calls neo. the engine is an sr20ve or sr18ve or sr16ve. its vvl for varitable vale timing. (sp?) on the ga the intake cam is adjustable for when the valve opens or closes. on the sr**ve it can control how long and how far a valve is open buy sliding the cam back an forth using a rpm trigger to activate it around 6000rpms. its the same concept as honda's v-tec, but with what we all love... nissan tourq. im no expert on this engine and i dont know a whole lot about it, this is what i have gathered, so a more well informed person can correct me (and please add to) if any of this info is wrong.
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Originally posted by Benjigil okay, so on the SR20 motor, you are saying that there is another set of cam lobes. similar to v-tec ?. I am very familiar with V-TEC, I am just trying to find out how Nissan's version (on the SR20 [s14]) differs, or relates to it.
thanks again for all the info guys
VVL never came on the S14.
VVL is Variable Valve Lift. Lift being the key term. Many other Nissans have used some sort of Variable Valve Timing. Timing control basically advances and retards the timing in relation to engine speed. VVL is very similiar to vtec in that it actually has two sets of cam lobes and at a certian speed the second (High lift cams) activate and you get more power. It has these lobes on the intake and exhaust cams (of course) BUT on a Nissan you can activate the intake and the exhaust cams seperatly. So you do have three stages, Low Intake+exhaust, High Intake+Low Exhasut, High intake+exhaust. Still not sure what engine you are referring to. VVL was only offered on FWD engines.
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