Which Engines Have Vvt?

[r33cruiser]

sup guys. ive been getting some confusing comments about the rb25det engines.

i have a s1.5 r33, basically a s2, but have a s1 frnt bar.

i have a s2 engine etc.

just wondering if this engine DOES have vvt?

and if so how can i identify it.

i pointed out the bulge from the cam cover, and aparantly that is the angle sensor, so how can i prove whether or not i have vvt?

and would any of u have any pics??

cheers

[paulr33]

it doesnt have VVT, VVT is found on the honda b16 (aka vtec) and also on the evo lancer (mivec).

the skyline (R33 and R34) have nvcs which is variable cam timing

the right solenoid (looking from the engine bay) is part of the nvcs system and it operates from the stock ecu and kick off point is around 4500rpm

so below 4500rpm its active to increase torque and midrange and then it kicks itself off to let normal cam timing take care of things

http://nissanskyline.6te.net/NVCS.htm

NVCS is the acronym for Nissan Variable cam system, it is found in the RB25DE, RB25DET and the RB25DET NEO. NVCS is not to be confused with Hondas V-TECH system which alters lift and duration high in the rev range to give higher peak power. Nissans system uses cam phasing to increase low to mid end engine torque.

Optimal valve opening and closure position for a given duration is different for every RPM and load combination, NCVS gives the engine the ability to take these factors into consideration and alters the timing accordingly. This is done using an electronic solenoid which adjusts the rotation of the cam by a maximum of 20 degrees, the solenoid is controlled by the engines ECU.

The RB25DE and RB25DET found in the R33 Nissan skyline only use the NVCS system on the intake Cam. The R34 Nissan Skyline is equipped with the NEO version of this engine and both intake and exhaust cams use the NVCS system. The RB20DET and RB26DETT do not use NVCS.

Torque curve of a VG30DETT with NVCS off and on notice the low to mid torque increase with the system turned on.

[r33cruiser]

nice, very informative cheers

[Eug]

it's early saturday forgive me; but arent' the valves controlled by the cams and their lobes?

so by altering the camshaft, you are altering how the valves work.

i understand that the systems are different VVT vs. NVCS, but how?

[Bass Junky]

This is technically incorrect Paul

The R34 doesn't have the NVCS on the exhaust wheel.

The difference with the NEO is that it actuates the NVCS slightly differently. There was talk that it was infinitely variable, but I have had this disputed by a couple of tuners.

I don't know the exact way that it works, but it's only on the Inlet side.

[R338OY]

NVCS is not to be confused with Hondas V-TECH system which alters lift and duration high in the rev range to give higher peak power. Nissans system uses cam phasing to increase low to mid end engine torque.

Yeh i notice on my RB25 the good mid-range torque, and then it drops off considerably after 6000rpm. Guess it has it's bonuses compared with VVT and the high-range power abilities of the Honda system.

Would be good if NVCS worked throughout the entire rev range though...