Supercharged LS3 Help - Knock Retard

[Lazarus]

Here are two logs from tonight. I still have a stumble when accelerating while cold and in OL. It almost looks like it's too rich? That's in the first log. The second log here has some KR. Also threw a P0300 random misfire CEL while idling. Fun fun fun....argh.

11192016.hpl
11192016_2.hpl

[10_SS]

Cool, thanks so much guys. I have 10% throttle for PE enable up to 2500 then 5% at 3000 and 3500 and then 0% the rest. I had no idea the PCM translates that number a bit different. I was just comparing a lot of other tunes originally...which I see now can be dangerous. Can't thank you guys enough. cc-rider, that's some good stuff about the airflow gain table, thank you. I checked my cylinder 6 spark plug and the gap was pretty big. I have a new TR6 and I'll gap it 0.027. Hoping this was the issue with the cylinder 6 misfire.

I'm pretty sure if you log "PE TPS" you will see that is matches 100% with the table "PE Throttle/Pedal" ECM 12420. No other TPS value comes close. I switched mine from enabling PE from the stock SS based off MAP, and went to the ZL1 method which uses TPS instead... ZL1 has low MAP enable like 15kpa, and PE Throttle/Pedal set to 12-19% depending on RPM. You'll eventually realize setting PE based off MAP with a supercharger is too slow since there is already pressure at the MAP sensor/intake ports when the sensor/computer/injectors start to react. TPS is much faster.

[Lazarus]

I'm pretty sure if you log "PE TPS" you will see that is matches 100% with the table "PE Throttle/Pedal" ECM 12420. No other TPS value comes close. I switched mine from enabling PE from the stock SS based off MAP, and went to the ZL1 method which uses TPS instead... ZL1 has low MAP enable like 15kpa, and PE Throttle/Pedal set to 12-19% depending on RPM. You'll eventually realize setting PE based off MAP with a supercharger is too slow since there is already pressure at the MAP sensor/intake ports when the sensor/computer/injectors start to react. TPS is much faster.

Interesting. I just tried using that approach and you are right. It seems to enter PE at soon as I stab at the throttle. I think I like this. My trims look better in this log too. BUT I still have KR around 2k rpm under boost at 11 degrees? What is going on? Argh.

11202016_4.hpl

[Lakegoat]

I don't understand why a LSA blower is any different from a TVS2300 from Magnuson. I am running about 11# boost and 18 degrees at wot and no knocks. I changed from the TR6 type plugs to BR7EF--non extended plug with .025 gap and got rid of some of the occasional hiccups at load. I have an e40 computer so I don't have all of the tables as you do to play with .

[Lazarus]

I don't understand why a LSA blower is any different from a TVS2300 from Magnuson. I am running about 11# boost and 18 degrees at wot and no knocks. I changed from the TR6 type plugs to BR7EF--non extended plug with .025 gap and got rid of some of the occasional hiccups at load. I have an e40 computer so I don't have all of the tables as you do to play with .

I'm beginning to think something in my exhaust is buzzing at that rpm, possibly causing a false KR. Or maybe it's burst knock and not KR. I'm reading up on as much as I can and trying to see what my best attack will be. Thanks for feedback on the plugs, I could certainly swap the TR6s for those easy enough.

[rao]

Burst knock retard will not show up as KR; it just reduces timing.

[Lakegoat]

I would get that wideband in front of the cat also.

[schpenxel]

Burst knock retard will not show up as KR; it just reduces timing.

The problem is if you hit "yes" when it asks you about using the generic sensor for knock retard, burst KR actually IS included in what it uses then. I don't agree with it being like that, but that's how it is right now. i.e. it basically uses total knock retard instead of just plain knock retard

[tbrtuning]

Should you avoid the practice of using the generic sensor PID?

[schpenxel]

Generally you should use the generic ones (IMO). Makes it way easier to switch between different vehicles if you tune more than one

But in this one particular case it doesn't work quite as intended

[Lazarus]

Generally you should use the generic ones (IMO). Makes it way easier to switch between different vehicles if you tune more than one

But in this one particular case it doesn't work quite as intended

Good to know, thank you! I used a scanning config already setup, and I bet it is using a generic sensor. I'll check that now. I'll also add the burst knock PID.

[Lazarus]

I would get that wideband in front of the cat also.

Ok, I will do this too. When I do that, I just have to force OL mode with the VCM control right? Completely disconnect primary O2 or leave it attached but tied out of the way? This will help me tune the stumble I have when running OL before the O2s are warm enough for CL. I've modified the OL EQ table vs. temp to keep all values at least at 1. I noticed my stock G8 tune (and current) has a "High Driveability Index Fuel Startup" table that is disabled. That EQ table has minimum values with coolant temp. Most tunes I'm comparing to have this feature enabled. I'm guessing this would be safe to enable for my tune?

[schpenxel]

I'd just have another bung added pre-cat. I've done that on all of mine.. $40 and an hour or so and you'll be able to use the wideband and leave it in closed loop too

[Lazarus]

I'd just have another bung added pre-cat. I've done that on all of mine.. $40 and an hour or so and you'll be able to use the wideband and leave it in closed loop too

Gotcha; I have these cats. Would you recommend having the bung welded in on the opposite side of the O2 or on the bend before the cat?

solo-cats.jpg

[schpenxel]

I'd probably do opposite of the existing O2 if there's room for it to fit once the cats are installed on the vehicle

I think either will work though

[Lazarus]

I'd probably do opposite of the existing O2 if there's room for it to fit once the cats are installed on the vehicle

I think either will work though

Ok cool. I'll remove the cat in the next day or so and see if I can get that welded in over the weekend. Thanks for your help!

[andrew1988]

i noticed you have COT enabled in your tune. you should disable it so it cant screw with your fueling.......sorry i just saw you have the temp thresholds maxed.

[Lazarus]

i noticed you have COT enabled in your tune. you should disable it so it cant screw with your fueling.......sorry i just saw you have the temp thresholds maxed.

I have the enrichment set a little less aggressive than stock. 1.07 compared to 1.3 stock, but the temp thresholds are still stock values. Is there risk to damaging the high flow cats if I turn COT off? I also have the stock Cat Lightoff timing tables too. I saw a lot of tunes zero out the values there but I'm assuming they're running no cats.

[schpenxel]

What kind of setup are you running? FI or NA?

[GHuggins]

I don't understand why a LSA blower is any different from a TVS2300 from Magnuson. I am running about 11# boost and 18 degrees at wot and no knocks. I changed from the TR6 type plugs to BR7EF--non extended plug with .025 gap and got rid of some of the occasional hiccups at load. I have an e40 computer so I don't have all of the tables as you do to play with .

Little more pricey - not bad though - roughly 11 or 12 a plug, but I would highly recommend the Brisk Racing GR14S plugs - same setup as the BR7EF's, but you no longer lose the cruise and idle manors plus they don't require the spark energy being that they're silver... We went to using them and haven't looked back...