Knockng When Going WOT

Hi guys, this is my first real tune. The car is a 2010 Camaro LS3/M6. It has a Huron Speed twin turbo kit with 58/62mm turbos, otherwise, the engine is stock. I'm tuning MAF only OL with PE enabled. I'm getting knock retard anytime I mash the throttle. I'm down to 8 degrees of timing on 11ish lbs of boost. Turning the boost down still has knock and turning it up makes more knock, so I'm guessing the knock is real. I run 93 octane (up to 10% ethanol) with no meth. Is 8 degrees of timing still too much? Or am I missing something. Whats odd is it starts knocking long before it even commands PE or drops timing, so by the time it gets to PE and the timing drops, its already pulling more. Attached is the tune and latest log. Thanks a ton!

Cant open your tune file.

I'm no expert and my application is different but I do have the same heads with a turbo.

I looked at your logs and your timing is doing some weird stuff and it plummets from 20+ degrees to 6 degrees in one frame when you go into boost. Check your adders and smooth out your table.

Your fueling is pretty lean in a few spots like 1.06 when commanding 1.0 at 2600rpm part throttle causing knock and the knock is carrying through even after it richens up.

Your PE ramp must be at 2? Lower the PE enable so it comes in sooner and lower the ramp rate to 1.5ish so it will start to richen up before you come into boost and then be to your commanded by the time the boost starts to ramp up.


I had to drop timing with the turbo compared to NA even before boost. I dropped 1-4 degrees from .40g down to the boost regions from 1800rpm to redline to get rid of knock.

odd that it wouldn't open for you. Im using the latest beta, maybe thats why? Not sure, it opens for me though. Yeah the timing table i just adjusted the wot table but im seeing now that i should go ahead and start lowering the tip in areas as well. And im still working on the maf but I was concerned about the knock going wot. I guess ill start lowering the tip in areas and see what that does.

Still chasing issues. Any advice? I've cleaned up the timing tables a bit as well as lowered some spots, changed around the PE table so its not going full rich outside of boost. Still getting random knock. It is repeatable. If I'm in 4th or 5th gear and give it alot of throttle at low rpm it will knock every time, even if its not building boost.

Anything under or at like 1 degree isn't harming anything when you are at like part throttle.

I do not suggest mirroring the timing tables because you are not allowing the computer to use the low octane timing table as designed. If the low octane timing has less in it, it can pull the timing and use the knock learn factor help pick the timing until it is gone, then it returns to normal.

Your MAF curve is really bad, it's not smooth at all. If you compare it to a stock curve, your fueling is all over the place. Not sure how you are using your wideband error to copy/paste your data in there.

Where is the MAF in the charge pipe?? It is by a bend or something because I also noticed that you could be steady in the throttle, boost slowly ramping in and the MAF values just start to jump up and down like there is turbulence in the airflow coming across it.

Even in low boost area's in that log you are far richer than commanded. The computer requests .80 lambda but you are getting .70 to .73 lambda which is really rich for such low boost levels. Some may not use the boost enrichment function but in many applications you can make it work pretty well. You'd have the PE section request something like low 12's AFR and then start the boost enrichment at that value and continue to add in fuel as boost rises. Slowly reaching a target of say 11.5 afr by like 6-8psi. This way you are aren't over fueling it when you don't need it.

Also for example you can be at 80-90kpa and it's already commanding .75 lambda, your wideband is close to that too and that's is way too much fuel for not even being that far into the rpm range or throttle. Over fueling can cause some of the knock too.

Change the PE and BE settings and see if it helps any. Try like 90kpa for PE with a leaner AFR, have BE come in at 110kpa and slowly have the fuel brought in as boost rises. If you get the fueling squared it may allow you to bring some timing back in. Also you may have to make the knock sensors a little less sensitive in these cars.

I've tried smoothing the maf table, but every time i smooth it and then datalog, it takes me right back to the jagged hell hole its at now. So i pretty much stopped smoothing it. The Maf is in the middle of a 2.5-3ft piece of pipe maybe 2 ft away from the tb. During crusing, it drives smooth as can be. Even when going wide open throttle it feels smooth, until it starts pulling timing. I took 4 more degrees of timing out of the whole table and it still knocks the same amount in the same spots. I can repeat it, but can't get it to go away. Here is a log with the 4 degrees pulled. I will try to smooth out the maf again, and adjust the pe and be tables as suggested.

Another update, took the advice on the pe and be tables, as well as smoothed out the maf to get rid of the peaks. Still picking up knock retard. Took 2 degrees of timing out of the area that was picking up kr and did a quick adjustment on the maf table, still getting kr. The car does feel a bit smoother with the pe and be tables populated tho, so thats nice.

Also, my MAF error graph is within 5.5 percent across the board. Should be even closer next time I log it.

got some vp110 to dump in. Will log with it and see how it looks.

so, even with 110, still picks up some knock retard. I've gotta assume this is false, unless my spark table is wayyyy off. Car seems to be richer than commanded everywhere, so I don't believe it is going lean at all. Attached are both if somebody with more experience can take a look at them and see what they think.

Maybe take a look at the plugs. That will tell you if you’re lean, at least. Lotta money on this engine.!!

Attachment 89842

as mentioned before

your maf curve is a bit off

also very low ignition will cause knock.

is your plugs gapped properly

yes, plugs are gapped to .25 or .28, its been a while I don't remember exactly, but they were gapped where everybody else gaps theirs with similar applications. I had the ignition higher, but on that particular file, i had been taking a bunch out just to try to get rid of the knock. I'm pretty sure its false so I dialed back the knock sensors a bit and all is well.