As above at what RPM's does it kick in and when does it stop? Reason I ask is because the very latest SAFC from Apexi has both fuel and VTEC control and I was thinking I could use it to tune my car and also have the VVT kick in when I wanted it and stay on until 6500rpm or thereabouts. Need some definite answers and opinions on this one. Cheers Rich
Stupidly high Rick, 5500 revs. You can feel the kick on the NA easily. I am going to change it to 3500-4500 when Ii get the microtech programmed.
Think it normally starts at 5,900rpm. If you get your ecu socketed you can change it to what ever you want.
According to the manual (pages EF&EC29-300) the valve timing control solenoid valve is off at idle and high speed and on for low to medium speeds. Does not state actual RPM however.
I haven't tried with datascan but perhaps it could tell you when the solenoid is on or off. Or maybe someone who has Conzult could find out?
im getting my ecu chipped, what do you reccomend having the vtt kick in at? 3500-4000rpm? would this help boost spool? more torque? what are the exact benifits?
VTC works at low to mid revs and cuts out at high rpm...... When Nissan designed the VG30DE and TT model engine, they employed a method of manipulating the intake valve opening/closing time with respect to the crankshaft position The VTC system is designed to increase valve overlap through the low to mid range RPMs to help clear out the exhaust gases in the combustion chamber, and the point at which releasing the VTC to provide optimum power higher in the rev range will vary from motor to motor (dependant on mods & condition). When the exhaust manifold is at greater pressure than the intake manifold, the valve timing advance needs to be released to reduce the additional valve overlap. The point at which the VTC should be released can be determined on a dyno using the max boost setting you intend to run. If you do a pull with the VTC set to 500rpm (this will cancel VTC) and then do a similar pull with the VTC set to 500rpm above your rev limit (this will always run VTC) then overlay the two graphs and note the point where the two graphs intersect (at highish rpm). This is the point where you want to set your VTC release rpm value. This will maximise your power by allowing the VTC to enhance low and midrange up to the point where the exhaust pressure starts to exceed the intake pressure (creating blow back) and then releases the VTC and limits overlap for maximum power at high rpm. In the VTC mode, the camshafts are advanced an additional 10 degrees. This produces 18 crankshaft degrees of valve overlap. The stock VTC control system with Nissan's parameters creates 18 degrees of overlap to occur at lower RPM but then returns to 8 degrees at higher RPM. Hopefully this will help people understand it a bit better.
kinda all depends, a most tunes set it at 4600ish. When the VVTC solonoid shuts off it advances the intake timing slightly. So it will depend on if you adjust your base timing maps as to where you want it to switch off.
