ddnspider

iTrader: (26)

I wouldn't sweat it if it's at the shift, very likely it could be drive train noise inducing false knock

2MCHPWR

iTrader: (10)

do you think the timing is too high in between the shifts? 35 degrees. not sure what is normal

ddnspider

iTrader: (26)

Even if it is, you're not going to hurt anything during a shift.

2MCHPWR

iTrader: (10)

Do you think that I should try raising this value:

Knock Sensor Level vs. Tip In TPS: Used to increase, decrease Knock Sensor sensitivity during throttle transitions.

currently set at:

15 15 15 15 15 15 15 15 15 3600 RPM--> 13 13 13 13 13 13 13 13 13 13 13 13

ddnspider

iTrader: (26)

I think you should leave well enough alone and done sweat the small stuff.

xRelapse13

iTrader: (21)

What you're seeing here is actually 1 instance of KR and then the PCM decaying the retard from that value. If you were to get more KR it would come up as separate steps up in the line signifying individual KR events.

2MCHPWR

iTrader: (10)

update:
changed out the plugs for new TR55's. While removing old ones, I found oil on the threads of the spark plugs. Led me to believe my pcv / catch can wasn't set up right. So i simplified it:

1. capped vent on drivers side valve cover
2. capped vent on the rear of passenger side valve cover
3. front vent of passenger side VC to catch can to port on mouth of intake

Then I did 4 logs.
Below is 3rd gear WOT with 3 instances of KR, then a short burst in 4th with KR only in the transition phase of giving it more throttle. The last burst is 4th gear only with no signs of KR:





Here is another log, in 3rd gear only, which shows 2 instances of KR in the ramp up phase going to full throttle; once in WOT, there is one instance of KR, wideband shows 12.43 and timing is 19.5:




The 3rd log, also only in 3rd gear, shows 2 instances of KR, the first one is the biggest at 1.4 degrees, 19 degrees timing, 12.5 on the wideband:




The final log is for 4th gear only and only shows a baby tiny amount of KR (0.3 degrees and you can barely see it in the graph with the cursor over it), at 20 degrees and 12.47 a/f but goes away quickly.




So my next change is going to be:

• make the transition to PE more aggressive. Originally had it reference PE table at 10% but I moved that back to stock but I’m gonna try it how the tuner originally had it (10%) because I think it’ll get rid of the transitioning KR as I roll into WOT because its still lean in that transitioning section
  
• most of the KR is between 2000 and 4800 at about 12.5-12.7 so I’m gonna richen up the PE table between that RPM range to about 12.3 to see if it has an effect on the KR

Thoughts?

ddnspider

iTrader: (26)

I'd like to see you leave the af where it is and set timing to 25 degrees and see what the difference in knock looks like.

kingtal0n

iTrader: (1)

1. There should be a table that injects a "pump shot" of fuel when you open throttle quickly. Adjust it so it pushed the A/F ratio below your target during a sudden change from low to high throttle position. i.e. if your A/F target is 12.8:1 at 2800rpm when you go WOT, make it so that during a 2800rpm cruise at 15:1, you can mash the pedal and see 12.4:1, and it gradually leans back out to 12.8:1 or whatever target. The maf is too slow to react to the sudden change, it always lags behind. Just like with a carb, the main jets lag behind, so there is a pump shot to help it through the pressure drop region.


2. between shifts, or anytime the user lifts from the throttle into a high vacuum situation at high RPM (2800+ perhaps) , allow the A/F to wander to the 13's briefly to cool things down. i.e. as you lift from the throttle (intending perhaps to downshift and run the engine hard) and the motor wanders into the 13's it helps ensure that whatever comes next, there was a moment of low-load with plenty of fuel hanging around to wet things down (it sets the stage). The last thing I want after an hour long cruise at 15:1 is to lift and see it go even leaner, just before I put the pedal down into a downshift.

3. You can help eliminate "false knock" by adjusting octane. After several confirmed runs where knock seems to occur (as you have done) put some race fuel in the tank and re-run the engine. Anywhere you still see the exact same pattern is suspicious of false knock and can be adjusted for if everything else falls into place.

4. Oil is a contributor to engine knock, it raises compression ratio and makes a filthy mess. If you think some may be hanging around the combustion chamber it might be time to start thinking about cleaning it out, water injection or seafoam I guess, things like that bother me, I can't sleep if there is oil in the wrong places. Best way is take the engine apart and manually scrub it off Seriously though, for a healthy engine, a good air filter, and proper PCV system are a must.

2MCHPWR

iTrader: (10)

so you are saying to increase timing? to see how that affects the KR?

2MCHPWR

iTrader: (10)

OMG I fixed it finally. no more KR.

so on march 23, i made 2 changes but they didn't fix anything. the 2 changes were:

1. 1) richened the mixture up (12.32 AFR) in the mid-range where I was getting KR (between 2800 rpm thru 4800):
   
   
   
2. 2) made the transition to the PE table more aggressive:
   
   
   

Still was getting small instances of KR in 2 consistent places:

1. applying throttle
2. sometimes in middle of 3rd gear

My gut feeling was that it is false KR.
So tonight i made three changes, mostly all related to desensitizing the knock sensors:

1. 1) Knock Sensor Global Gain vs. MAP vs. Cyl: gonna increase these numbers 15% which is the same as lowering the sensitivity. Below are new values:
   
   
   
2. 2) Knock Sensor Level vs. RPM vs. Cyl: since these are stock z06 levels, I think my valve train is noisier, so I will increase these numbers (reduce sensitivity) by 1.0:
   
   
   
3. 3) Knock Sensor Level vs. Tip: these are stock z06 levels so again, I will decrease Knock Sensor sensitivity during throttle transitions by increasing values by 1.0:
   
   
   

and here are 3 logs:
This is the first pull,leaving the rest stop on highway. Started in 2nd gear and went to 6000 rpm, 3rd to 6100 rpm, and 4th 5500 @ 120 mph, same as ¼ mile trap speed.
Only got 0.4 KR rolling into 2nd gear at 50% throttle and was gone at 100% TPS:



The second data log was after the u turn to get back on to highway. Started in 2nd gear and this time no KR even in 2nd gear, 3rd gear to 6000 to RPM, then feathered 4th gear because of traffic but then got on 4th to 127 mph. no KR anywhere to be found:




Last pull was only 4th gear to simulate a dyno pull. No KR




I think the last steps are to lean it out a little bit and play with timing a little bit. Probably will do it on a dyno.
Thoughts?

ddnspider

iTrader: (26)

I would be concerned you decreased the sensitivity so much it won't pick up real knock now. You did all that and only picked up .4 degrees in 1slot in 1 log. If you lean it out or add timing and knock comes back I'll buy it fixed it. Otherwise you have no idea if you went too far.

ddnspider

iTrader: (26)

Ps...man that maf curve looks ugly lol

kingtal0n

iTrader: (1)

I agree the maf signal seems filthy. See if you can do something about that noise. It could be that you do not have enough straight pipe before and after the maf, causing a turbulence issue.

2MCHPWR

iTrader: (10)

i will work on that but don't know how (yet). this is a MAF only tune. if you have any good links, post em up. thanks

ddnspider

iTrader: (26)

simply log your BEN or correction factor for commanded vs. actual a/f and then tweak the cells in the MAF curve that are off based on the BEN. Can you post up a picture of your MAF curve?

RonSSNova

iTrader: (3)

What is BEN?

ddnspider

iTrader: (26)

It's just a correction factor, i.e a BEN of 1.02 means you need to increase the valve in the given cell by 2% or multiply it by 1.02 because the actual af rato is leaner than it should be. I think it stands for Base Efficiency Number or something like that. For example, if my commanded is 14.7 and my actual is 15.1, than by Ben= 15.1/14.7=1.027

joecar

Traditional BEN was defined as wideband_AFR / commanded_AFR, as ddnspider showed by example above;

and it was named after Ben Strader at EFI101.com

the term "BEN" has become common usage for the correction factor you apply to VE or MAF tables.

I've been tuning using BEN defined as wideband_Lambda x commanded_EQR, this form is independent of the stoichiometric AFR assumed by the calibration and/or the wideband.

joecar

sidenote:

I've been educating my customers to use the terminology "Lambda" for wideband fueling measurements and "equivalence ratio" for commanded fueling...

this avoids confusion over the phone: "AFR was 11.7" (was this wideband or commanded...?) vs "lambda was 0.76" or "EQR was 1.25" (it is very clear which is wideband and which is commanded).