Nistune Forums

In this config (bin) the solenoid will not engage before you have reached TP>60.
Set this to 10 and test drive.

(how have you tested ?)

On Z32 the VTC is dictated by load, on RB 25 by RPM.


If it still does not work set
RPM RECOVER to 1500
and
RPM CUT to 5900

fu^&* VTC it works now

You are the man haha

i thought all the time that TP CUT - means when it should cut off not cut in....
arghhhhhh

ok - now we can start over.


PS. it is not comming up on the nistune
"You can monitor the activation in Nistune (see if flag comes on)"

it is working - but no green / red flag ????????


cheers mate

Hello,

Glad I could help ...

Yes, the cut is actually BELOW, not above.

I spent some time experimenting with VTC but in the RB25 it is on most of the time.
Also I never could really feel any difference, but will test on the dyno one day.

As for the 'Flag' not coming on, make sure

DCFlags2

is set when you connect to the ECU.
(There is this requester pop up asking what Nistune should monitor)

Have fun

there is a huge difference without VTC - it's all that RB is for with stock turbo.

low end torque hehe

stock turbo 0.5 bar without vtc - on dyno 240Hp and 250Nm
stock turbo 0.5 bar WITH vtc - 250Hp and 360Nm

same car / same engine / same dyno

If only

Are your figures for the same RPM?

Then your HP should also be 33% more (as is your torque figure)

HP=RPM*TORQUE

Can you post the dynos?

will do a test on wed - figs where from my memory ( different rpm figures for sure )
.... without vtc there was no way to spin 225/45 R18 on second gear with just pressing gas pedal..... with vtc on - it burns tires like crazy

will get it with/without VTC - 2 runs on stock nistune settings before we start playing with it

Good stuff, I always wanted to have a look at this.
I am sure it makes a difference ...

To disable VTC just set TP LOAD CUT to some silly (high value)

Also make sure the X-Axis of your dyno is in RPM. not speed.

i've been by the comp. today - and found 2 runs that we made some time ago....

1. vtc off - Nistune fitted and tested 0.5 bar on stock actuator

2. stock RB25det ecu with piggy back.... 0.6 bar if i remember on some mbc.

So a complete retune?

Can we get a graph of VTC on and VTC off with an identical tune and nothing else changed? would be interesting to see the difference.

will get it some time this week - have some work on client cars to be done first

I've done that before - it makes a massive difference. Chalk n cheese.

VCT on/off equates to 20 crankshaft degrees difference in cam timing. That's a lot.

One thing I've done a few times now on budget tunes is to simply tie the VCT on all the time. This gives same power curve all the way to the rpm where VCT normally turns off. After that the power tapers off a bit more than usual. But on std RB25DET it's only about 10kw right up the top.

PL

I think the manual for the Z32 states 8 degrees...
Not sure about RB25 though.

20 degrees would be a lot, so should quite make a difference.

All SR20's are 20 degrees. Not sure on the other engines cos they're not really my thing...

PL

something i've noticed a LOT of people miss when wiring rb25's into other cars is supplying power to the o2 sensor power wire. Its in the same plug as all the other important stuff. blue wire from memory. Thing is, it also powers the vct solonoid. If you've done a conversion and missed this wire, VCT will never work no matter what ecu its running.

Yeah, I've seen that lots too. Very common mistake.

For the SR boys - O2 sensor/VCT power wire on SR's is always brown. This brown wire also supplies power to boost control solenoid.

PL