working on an L67 tune (VX L67 10psi, enhanced tune, CAI and twin exhaust fitted).
Getting some knock on throttle movements, always seems to occur as the TPS increases, worse with large throttle movements I would take that to be a burst knock issue?
Not sure on how to rectify?
Thanks in advance
Last edited by immortality on Sat Dec 05, 2015 1:20 pm, edited 1 time in total.
If I read things correctly Burst knock is the PCM anticipating knock because of large throttle movements and pulling out timing in anticipation?
Looking at the log there are Knock Active Loop counts occurring at the same time so that would mean it's not Burst Knock but actual knock. Does that mean I need to look at Tip In spark?
Yeah, I had that thought too and added a little AE but it hasn't seemed to have made any difference.
On that subject the XDF has 2 AE tables defined, Acceleration Enrichment - Sync Delta TPS Multiplier V's Coolant - Drive and Acceleration Enrichment - Sync Delta TPS Multiplier V's Coolant - P/N however the P/N table seems to have more AE than the Drive table, does this sound correct?
The Drive table has no AE at 92°C ECT upwards?
Tables are also remarkably different from the VS_SC XDF.
The factory table has .14 delta multiplier @ 80°C ECT and 0 @ 92°C (~normal operating temp), I've increased that to .55 as well as before and after (68°C and 92°C ) I do all my WOT runs when the engine is close to thermostat temp (82°C, engine sits at ~83°C when cruising) +/- 2°C. I altered both the Drive and P/N tables to cover my basis.
I did a big jump because when I altered it a small amount it made no difference (.39 @ 80°C) it's probably to much now but I'll fine tune it at a later date. At least now I know it's safe and not relying on the knock sensors any more. Been busy preparing to lay some new concrete in a section of driveway so I've only been able to test things when going up the road to get bit's for the project, checking logs and then altering things as I have time before the next trip......
Now when you nail it, it goes where as before it would start to go and then you could feel it pull all the timing out.
Speaking of knock, on Friday when a truck decided to pull over half way on a on ramp giving stuff all road to get up to speed. I flogged it and it was hot that day and the engine was half on the gauge from sitting behind this truck going 20k, I encounter knock that was so loud I hear it over the engine and radio inside the car and it went for few sec at the top end and I dont think he ECU even did anything to retard the timing as it carried on until I went 3rd gear without any loss of power lol.
knock detection in the 808 is completely useless.
Sounds like it works a lot better on the later ECUs.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
I would take that to be a burst knock issue?
