Jump to content
SAU Community

Recommended Posts

Hey guys, I been reading up and apparently the series II RB25det's have NVCS which is like VVT/VVL.. and also apparently it is controlled by a solenoid somewhere on the engine... at the moment, untill I hit 4500RPM, the tourqe is nothing special.. but from 4500 to redline you get a huge rush of power!! its even noticable on my dyno graph...

Heres my question... is it possible to to have the solenoid always 'on' so that you have the advanced timming on bottom end too?? or to even connect a switch to it similar to the "high boost mode" idea???

Anyone got a pic of this solenoid??

Regards,

Sarkis

Link to comment
https://www.sau.com.au/forums/topic/113681-rb25det-nvcs-concept/
Share on other sites

the VCT solenoid is the hexagonal thing coming out of the side of the head near the end of the fuel rail and the water outlet...

its a simple on/off solenoid which allows oil to flow into the unit on the end of the cam shaft, and change the advance/retard on the cam.

i actually believe that its "on" from about 1500 to 4500 and OFF before and after that.. so you actually sound like you want it off.

you can do a run with the solenoid unplugged and see if it helps your results, but i dont think it will..

im doing a kick off point rpm test at our next dyno day for the NVCS on the rb25. you do a dyno run with stock setup (kicks off at 4500) then plot power w/rpm. then turn nvcs off (make it kick off at say 1200rpm) then dyno run again. plot it on the same chart and the point where the two intersect is the ideal rpm kick off point. im not sure how useful it will be (if anything at all). but still something fun to try.

powerfc users can alter the kick off point via datalogit

right so it does vary a bit on each engine, sweet as.

in the powerfc i can only change the rpm point.

so it comes on always at about 1400 and then off again at 4500.

so you found the ideal kick off point is near 5500 once tuned ?

More linear power curve. If the cam changes to soon you can loose power and torque,if you can changes at 4500 and it needs to be at 5500 for example then you are giving up max power for 1000rpm right in the guts of your curve. Do a power run with the vvt off then do one with it on from start to rev limit and its easy to see where to switch at.

LINKS - Im currently running the Hi-Boost mode on my factory solenoid therefore constant 7psi... my car is fairly stock except for the split dump and 3" hi flow CAT and exhaust + K&N Pannel filter (165rw/kw) and at 4500 - 5000RPM i get a slight pop (at times) from the exhaust and a rush of power to redline! Its not a misfire for sure cause theres no hesitation and the coils + NGK plugs are only 6 months old.. Im definate its the NVCS kicking in via ECU and CAM gears... all i was hoping to do is get it kicking sooner to get more bottom end... i guess ill need an aftermarket ECU...

Do you guys think resetting my factory ECU would help after getting the exhaust or any other mod fitted?? any benifits?

Cheers

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Who did you have do the installation? I actually know someone who is VERY familiar with the AVS gear. The main point of contact though would be your installer.   Where are you based in NZ?
    • Look, realistically, those are some fairly chunky connectors and wires so it is a reasonably fair bet that that loom was involved in the redirection of the fuel pump and/or ECU/ignition power for the immobiliser. It's also fair to be that the new immobiliser is essentially the same thing as the old one, and so it probably needs the same stuff done to make it do what it has to do. Given that you are talking about a car that no-one else here is familiar with (I mean your exact car) and an alarm that I've never heard of before and so probably not many others are familiar with, and that some wire monkey has been messing with it out of our sight, it seems reasonable that the wire monkey should be fixing this.
    • Wheel alignment immediately. Not "when I get around to it". And further to what Duncan said - you cannot just put camber arms on and shorten them. You will introduce bump steer far in excess of what the car had with stock arms. You need adjustable tension arms and they need to be shortened also. The simplest approach is to shorten them the same % as the stock ones. This will not be correct or optimal, but it will be better than any other guess. The correct way to set the lengths of both arms is to use a properly built/set up bump steer gauge and trial and error the adjustments until you hit the camber you need and want and have minimum bump steer in the range of motion that the wheel is expected to travel. And what Duncan said about toe is also very true. And you cannot change the camber arm without also affecting toe. So when you have adjustable arms on the back of a Skyline, the car either needs to go to a talented wheel aligner (not your local tyre shop dropout), or you need to be able to do this stuff yourself at home. Guess which approach I have taken? I have built my own gear for camber, toe and bump steer measurement and I do all this on the flattest bit of concrete I have, with some shims under the tyres on one side to level the car.
    • Thought I would get some advice from others on this situation.    Relevant info: R33 GTS25t Link G4x ECU Walbro 255LPH w/ OEM FP Relay (No relay mod) Scenario: I accidentally messed up my old AVS S5 (rev.1) at the start of the year and the cars been immobilised. Also the siren BBU has completely failed; so I decided to upgrade it.  I got a newer AVS S5 (rev.2?) installed on Friday. The guy removed the old one and its immobilisers. Tried to start it; the car cranks but doesnt start.  The new one was installed and all the alarm functions seem to be working as they should; still wouldn't start Went to bed; got up on Friday morning and decided to have a look into the no start problem. Found the car completely dead.  Charged the battery; plugged it back in and found the brake lights were stuck on.  Unplugging the brake pedal switch the lights turn off. Plug it back in and theyre stuck on again. I tested the switch (continuity test and resistance); all looks good (0-1kohm).  On talking to AVS; found its because of the rubber stopper on the brake pedal; sure enough the middle of it is missing so have ordered a new one. One of those wear items; which was confusing what was going on However when I try unplugging the STOP Light fuses (under the dash and under the hood) the brake light still stays on. Should those fuses not cut the brake light circuit?  I then checked the ECU; FP Speed Error.  Testing the pump again; I can hear the relay clicking every time I switch it to ON. I unplugged the pump and put the multimeter across the plug. No continuity; im seeing 0.6V (ECU signal?) and when it switches the relay I think its like 20mA or 200mA). Not seeing 12.4V / 7-9A. As far as I know; the Fuel Pump was wired through one of the immobiliser relays on the old alarm.  He pulled some thick gauged harness out with the old alarm wiring; which looks to me like it was to bridge connections into the immobilisers? Before it got immobilised it was running just fine.  Im at a loss to why the FP is getting no voltage; I thought maybe the FP was faulty (even though I havent even done 50km on the new pump) but no voltage at the harness plug.  Questions: Could it be he didnt reconnect the fuel pump when testing it after the old alarm removal (before installing the new alarm)?  Is this a case of bridging to the brake lights instead of the fuel pump circuit? It's a bit beyond me as I dont do a lot with electrical; so have tried my best to diagnose what I think seems to make sense.  Seeking advice if theres for sure an issue with the alarm install to get him back here; or if I do infact, need an auto electrician to diagnose it. 
    • Then, shorten them by 1cm, drop the car back down and have a visual look (or even better, use a spirit level across the wheel to see if you have less camber than before. You still want something like 1.5 for road use. Alternatively, if you have adjustable rear ride height (I assume you do if you have extreme camber wear), raise the suspension back to standard height until you can get it all aligned properly. Finally, keep in mind that wear on the inside of the tyre can be for incorrect toe, not just camber
×
×
  • Create New...