draper

Everyone who tried to change timing with Cobb or Uprev couldn't advance much, maybe 2-3 degrees. Any major timing advance and ECU responds to ultra sensitive knock sensors and reverts it back to previous timing.

Apparently Uprev only gives access to IGN tables, Cobb gives you access to these plus knock overlay. As per Cobb's documentation and technical support, ecu can look at these tables and ignore knock.

Haven't tried it yet but this might help in advancing the IGN little more ?!

Q8y_drifter

Assuming the knock sensors have accurate detection, if the ECU will advance the timing as far as allowed (without introducing knock), then what benefits do we get by ignoring the knock sensors?

draper

Aren't AFR and Ignition timing the only two variables available to tune a NA engine like ours.

AFR is tunable, IGN timing is only about 2-3 degrees. You saw my replies on the370z.com, based on Megan370z post and the response he got from Uprev :

this is a copy paste from an email Ive been exchanging with Jared (Uprev)

This has been an ongoing complaint about the VVEL engine controllers. They do VERY advanced knock control. The ignition tables are only a starting point, the ECU will monitor the knock sensors and run as much advance as it can run before it starts to hear pinging. The only place these tables are of any use on the VVEL engines is to smooth out the power and for forced induction so that you can give the ECU a safe starting point so it doesn't ping for the first few pulls every time you start the engine.


We did tests on the ignition tables early on and found that if you pulled 15 points out of the ignition table, the power and ignition would drop dramatically on the first run after the adjustment, but after a few consecutive runs the ECU would advance the ignition right up back to where it was before. This goes for NA and FI applications. It's going to run what it's going to run based off of the knock sensor feedback. You really can't force it to run more advance.


We are looking for parameters to adjust the knock sensitivity and gain and whatnot, but our developers are really backed up with development projects and I really have no idea when they're going to be able to dig back into the knock code on the VVEL ECUs.


Jared Ainsworth



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In the end trying to tune the ign timing wont give you much as the knock sensor wont like it , even if you don't hear a ping/knock with an knock headphone.

I did the same thing as what Uprev did by removing a bunch of timing , but the ign timing would go right back where it was originally no matter what.
you might gain a total of +2-3 advance on 91 octane but it wouldn't be stable if under some condition you get more.

soo we have to wait for Uprev to come out with some knock setting



Uprev is still looking into adjusting the knock sensitivity because this engine's ecu does very advanced knock control, this likely means that there is some more gains to be made through IGN timing. As your a tuner yourself and prolly know that AFR and IGN timing go hand in hand.

"even if you don't hear a ping/knock with a knock headphone", as per this either the knock is not too loud for the headphones or knock sensors are sensitive. Nissan knock sensors are known for their sensitivity.