Torque Knock PID - may have some progress...
- Thread starter ecoboostsho
- Start date
wasinger3000
New member
Have you received your 3 bar and Stat yet?FoMoCoSHO said:
Leading Edge Tuning said:As sensitive as the knock sensors are on these motors, it is a fairly common occurrence to see knock when you let off the throttle. There seems to be noise created from the TB closing.
As far as power going away in repeated runs, the tuning has safe guards based on IAT, coolant temp, cat temp, valve temp, flange temp, EGO temp...well, you get the idea...
I am not disputing this at all but just want to learn. Why would there be spark knock in a closed throttle situation with no load on the engine? Are you saying that the sensor "hears" the TB close and "thinks" that noise is spark knock???
I just cannot get my head around having spark knock and needing to pull timing when the throttle is closed and there is no engine load. I understand that these engines do cut off the fuel in a no throttle coast condition but I don't think that happens immediately after an abrupt lift. Does that have anything to do with it? I would love an explanation for this.
glock-coma
New member
What equation is everyone using on torque? I switched to the most current, and immediately started seeing +7 as my max. Before the switch I was seeing +4 as the high.
This is getting interesting. Now I'm not the only one getting a +7. I am using the most current equation. I got the +7 running 4X (3BAR). Running the 2BAR 4+ tune I got a max of +2. I flashed to stock last night but don't have any knock retard numbers yet on the stock tune.
Larrylu said:
Glock-coma has an Unleashed tune so his tuning parameters are probably somewhat different than ours. However, it is interesting about the change based on the equation.
Still, the difference in knock retard between your 4+ and 4X tunes when you used the same equation is a bit concerning.
SHOdded said:
Very good question about the boost levels they see when the KR is +7. Interestly, when I am WOT and highest boost, I never get KR. The only time I get the +2 is at a low RPM lugging condition and relatively low boost level. I have tried it when the car is not fully warmed up (150* or so) and fully warmed up (180*) and the KR on mine is the same either way.
Note that I am NOT disputing JT at all - but I am just thinking there is more to the high KR readings than just boost and temp.
I have not done the VTA so far and I'm running a 170 T-stat. Coolant temps usually hang in the low 180's regardless of the ambient. As Bruce points out, it is important to note that all else staying the same when I went to the old 4+ 2BAR I went from 7 to 2 positive knock retard.
glock-coma
New member
I'm still running the stock tstat and I am VTA.SHOdded said:
I've seen the +7 when the temp was 175* don' t really see it below that.
It only happens lugging in 6th gear. If I downshift it immediately goes to a lower+ number or -
Some data logs! Weird results. The only lift/knock event I have seen was with little throttle applied. There seems no reason for the 2 knock events that I had during my 30 min drive. I did stop for gas and heat soak could be the factor for that one. But the other?? There is also a WOT run to 60 and I had 0 KR even on the lift.
Spending a little more time with this I am not sure what I am seeing is true knock. I have found this. Interesting read.
http://www.zzperformance.com/blog/about-knock-retard-kr/
I believe that in these cases this not truly knock (detonation). But this is speculation at this point.
http://www.zzperformance.com/blog/about-knock-retard-kr/
I believe that in these cases this not truly knock (detonation). But this is speculation at this point.
Maybe we should be taking another look at the PID/equation for this gauge. A lot of the new PID's were amazingly pieced together with parts from multiple sources, with great collaboration and clever reverse engineering but every once in a while a gauge came with weird reading and often that showed a problem. Just saying what if? On the other hand it does make sense that for me any way, the most aggressive tune gave me a 7 positive, 4 negative, my next most aggressive gave me a 2 positive, 4 negative, and now my stock file so far is reading 0 positive, 4 negative.
ecoboostsho
New member
Larrylu said:
I'm totally open to the fact it isn't accurate entirely. The formula for this PID is something of a guess (even though it is a very simple formula). I will do some more logging specifically on this parameter and see if I can get a Hex/binary reading that makes sense. If I assume FORSCAN is correct I can see what values of knock correspond to what values in Hex and derive the formula. I technically did this the last time and ended up with the A/2 formula but I will admit that Forscan can interpret knock in quarter degrees and you can't get there with A/2 so something is off. It also returns at least two bytes (A and B) but the B value is always changing unless it actually sees knock. Almost like it is a counter or something to tell you that the sensor is still working and then when it sees knock it read the "actual" value. I don't know how else to describe what I'm seeing in the response from the car...I definitely would like to know for sure so let me keep at it and gather a few more sample points to at least see if this PID holds. My challenge will be that I almost never see greater than 2 degree of knock...once I think I got a 3.5...can't hurt to double or even triple check as this is a pretty important variable. Be patient with me though...My wedding anniversary was yesterday, my oldest turns 18 today and my 4 year old turns 5 on Sunday.
