Questions about timing on VP Commodore V6

[delcowizzid]

Knock sensor normally turns off around 3600-4000rpm due to noise .you can lower the rpm so it turns off sooner if you have a noisier motor ie cam etc .wheels pin and exhaust hitting on the body also set it off. There's also different knock filter boards on the memcals from each model

[silentshout]

Knock sensor normally turns off around 3600-4000rpm due to noise .you can lower the rpm so it turns off sooner if you have a noisier motor ie cam etc .wheels pin and exhaust hitting on the body also set it off. There's also different knock filter boards on the memcals from each model

Very interesting, if knock sensors turn off what would dictate the Knock retard kicking in around the same RPM and then 4krpm+ just being held at its max value?
are there other aspects of the engine that would enable knock retard without the sensor being active?

Reason for asking is same motor with the factory ecu still feels flat over 4000rpm, no where near as much as the 12p setup but its still noticeable.

[delcowizzid]

Check the knock sensor plug and the sensor itself down by the oil filter.if it isn't detected by the ecu it will go max knock retard

[vlad01]

That's false knock. I just disable the entire knock system as it's a problem that can't be worked around.

Years ago when I went through a total engine tune including spark on the dyno, this knock was still there (for me it was around 3k or so and up) even when I killed the peak timing to less than 10 deg. (MBT was 27.5 deg btw) and it made the car run like shit. Turning it off by making the scalar for ESC enable to max (around 150c).

The ignore knock table doesn't work, it's bug in 12P I reckon.


Keep in mind that the engine is slightly knock limited with 91 ron with long tube headers from Pacemaker, and quite knock limited with stock logs, but the stock timing is perfectly fine and you should never have an issue in 99% of conditions.

knock is very audible in these engines, and I can confirm that the stock knock system doesn't even recognize real knock and always triggers falsely. I find it more of a random knock signal generator for the ECU than anything it actually helps with.

Also, these engines are very tolerance of knock at least in an NA setup. I have never been able to find evidence of damage or knock occurring in any of my engine autopsies where I had of them knock badly due to previous owners loading in an ebay tune. So don't worry about hurting them. Ecotecs on the other hand though...

[antus]

I think, but its been a while, knock counts still counts, but its knock retard that is accurate. You disable it by maxing out the temp it turns on.

[silentshout]

Thanks all,

Given its only 75% of the timing the VP runs (earlier in this thread i compared the 12p out of the box timing and the VP timing and found the VP timing was more spicy presumably due to things like a marginally lower compression ratio etc)

The car only runs 98 and while it doesnt have pacemaker headers, it does have a set of the old school Wildcat headers, the 3-1 merge sits just above the steering rack, from memory the primaries are slightly smaller than pacemaker though.

Headers.jpg

As for the electric spark control (ESC), here are the details in the calibration, seems to be right up until 5000rpm (might not be to do with the knock sensors):

ESC settings.jpg

I think you guys are on the money that the knock sensor is either too flakey or something is up because combing through the logs again i can see here it logged 78 knock events on decel around 4000rpm with no TPS and bugger all timing considering it was still being throttled by the Knock retard.

Flakey sensor.jpg

If there are no major differences between the 12p fueling and the VP fueling (VE tables were near identical) then ill just disable knock, slap on the VP timing and listen for any detonation.
Wont do that until the wideband is on just in case it is a fueling issue.

[antus]

Here it is..

viewtopic.php?f=7&t=1396

Q. How do I enable or disable the knock filter?
A. There is no direct flag for this. Instead edit the scalar ESC params - Coolant temp enable. The knock counts will be used to pull timing above this temperature. To disable the knock filter (when it or the knock filter is not physically fitted) set this value to the maximum. To enable it again, set it to the default value of 56 degrees C.

[vlad01]

Yep thats the one.


As for the ignore counts table, yes it still showed counts, but I recall it did nothing to reduce or stop the retard itself at the selected rpms. My guess is maybe the counter overflowed and reset and somehow allowed counts to trigger the retard as per normal. 12P and other factory code do have bugs that I have picked up on over the years and I can name a few.

My first VP which had all the mods I still currently run in my current cars, it had heavy retard just cruising up to speed at most rpm ranges, it was at an even lower rpm than the OP's car.
This is when I first started to learn about tuning and how much the knock filter sucks on these. This is also where I realized most of the performance discrepancy from car to car was, where some retarded lightly to moderately, other's very heavily.

Turning off this system allowed all cars to level out and re-gain their intended power.

You'll never really have an issue running 98, so go for it!

[silentshout]

Thanks for all the advice everyone, Mate decided he was happy to send it, so we sent it.
Car feels great. I checked over logs and it looks like temps got super hot.

Also while trying to work out how to make the burbles more prominent i noticed the car wasnt going into DFCO at all.

Hunted around and noticed the road speed showing super low (as noted in the OP) big thanks to @Knackersjewels who suggested adjusting the PPK, was set to over 6k which i think is for the VR

Some heavy use of the search button in the forum and i found the info i needed, set that to 1501 (car has 3.7 LSD diff in it) which will bring road speed up above 22kmph

worked out that's also why the burbles were happening (because it never met the roadspeed threshold to go into DFCO but sounded cool as hell) this also meant it never met the road speed threshold to enable thermo fans while driving (leading to it running around 104 degrees after a solid rip and the car pulling timing based on the coolent temp vs MAP timing adjustment table)

So, moving forward have adjusted road speed input, disabled DFCO by setting Max RPM (i believe this is the rpm that the engine needs to be over to enable DFCO) to the highest it will go, have brought down that thermo fan a smidge to better align it to the current thermostat temp (this is temporary as he has an 82 degree thermostat to go into it where we will bump the fans down a bit)

Just wanted to say a big thank you to everyone, the tuning journey has just begun but hopefully will have some things to contribute later back to the forum.