Chasing some Knock 6.0 LS2 403ci

[Stroked06Goat]

0525am.hplSD Tune VErevamp iteration 6 final with NO MAF4 no ltfts changed dynamic air limits.hpt

2006 GTO LS2 403 stroked Voodoo crank, lsa heads, kooks long tubes. otr intake. SD tune (maf too erratic for me to trust quite honestly but i'll take suggestions. inserted a card style but minimal runner length on those otr intakes). 6 speed stick. Cam i'd have to dig up the specs honestly but its healthy. Was told dyno's 550hp from previous owner and never got any verification. Some day i'd like get a TVS2300 on top but anyway....

Read till i was blue in the face and there are lots of threads about spark and knock. I appreciate anyone that wants to take a look see if anything looks off. I am no professional tuner and maybe slightly more than a novice to adequate but, self taught by all the information here and all the expert guys here. VE looks good i think but... the question..... does the spark i'm asking for seem reasonable to say the least? Those knock spikes i've been chasing for a couple years. Looking at getting this to the strip this year finally and want to ensure first i am not going to hurt it...but second...leaving power on the table.

Appreciate any thoughts if anything jumps out at anyone. Car runs strong good drivability after dialing in the VE. Was pig rich for a while on the low end but worked that out. This log was in the morning and on a tank of 93 eth.
Thank You

[kevin87turbot]

That's an interesting way to use the PE Spark Advance vs EQ ratio table.
What's the compression ratio of the engine? Typically you'll find that you can run more timing advance after peak torque. You're around 20 degrees on the datalog at WOT. You might add 1-2 degrees at 5200 rpm, and 2-3 degrees at 5600-up rpm.

[Stroked06Goat]

Spark tables were entirely done by the tuner on the dyno. I did a lot of work on the ve, since if i had to guess they made it run, dyno'd it on top end....then made it safe with a bit of extra PE. You shoulda seen the VE to start. Looks like they literally scaled the VE by 25%. I gained 2mpg just by dialing the VE. So i suppose if the spark tables are odd, it doesn't surprise me. In full disclosure, the only spark work i've done is adding a bit on my stock 6.0 truck a few years back. I dont know anything fancy or what to look for other than knowing engines and 20* of spark shouldnt be that outlandish i wouldnt think, hence my question.
I'll have to dig up the paperwork i do have to see what the CR may be. It's the typical story...it was blueprinted...but when i called the engine builder they claimed knew nothing about it etc etc. Was built around 2010-2012 in southeast Pennsylvania, and i picked it up 2016. I do have the car build sheet at least with all the parts. Little research i'll be able to guess the CR.
I'll try your suggestion for sure on wot...i'll try and test it prior to a 1/4 mile run but...its tough on the street. this car scoots for how heavy. I'm used to old school 60s grunt engines so....first time i drove this ls2 past 5k rpms....it just keeps pulling with legs for days. I cant imagine it with a little boost some day but will likely need more tire. I appreciate you taking the time to look. I'll report back!

[DB5249]

tune looks rough, if spark was done on dyno he should have pulled a few degrees after he took it off, a dyno can load a motor heavily and on the street an engine can rpm up a lot easier generating more compression needing less timing. in other words it might be causing detonation issues. and spark maps should not match the low octane for safety reasons, the only reason in my opinion to do that if is you have removed the maf and installed a iat sensor. cel for maf will often keep it in a limp mode only using low octane table, but the table is there for a learn value scenario. cam could sound more aggressive with tuning, maf is failed which is good for speed den. if you are tuning with a wideband in scanner go to vehicle controls/fuel/ and turn off closed loop, turn off ltft, and reset fuel trims, log and then adjust ve table.

[Stroked06Goat]

Did the VE with my wideband and looked within a couple percent. I thought that part of it was spot on. And yes that log runs in SD as i got the car without a MAF (OTR intake). Put a card style in but its too erratic for me being such a short intake.

You're saying the spark looks rough, or VE?

[Stroked06Goat]

Found one build document.Screenshot 2022-05-31 085807.png

[DB5249]

removing the iat that is built into the maf can swing your fuel ratio 20 percent rich, so i would highly recommend putting a sensor back on your car you don't have to, but having an iat can help you tune your spark tables where high iat might cause knock letting the car pull timing after a certain iat level, same goes for fueling, having a car tuned with a working iat also lets you tune for nitrous pretty easily as you can adjust tune to pull timing and add fuel when you momentarily disable iat sensor. Timing IMO is too aggressive for anything but a sheet metal intake down low or any short runner intake. and ve table needs better transitions, i would start by choosing lower gears and revving it out slowly and higher loads to populate the ve table as much as possible. if you live at a higher elevation your timing map might be normal for your area as well.

[kevin87turbot]

removing the iat that is built into the maf can swing your fuel ratio 20 percent rich, so i would highly recommend putting a sensor back on your car you don't have to, but having an iat can help you tune your spark tables where high iat might cause knock letting the car pull timing after a certain iat level, same goes for fueling, having a car tuned with a working iat also lets you tune for nitrous pretty easily as you can adjust tune to pull timing and add fuel when you momentarily disable iat sensor. Timing IMO is too aggressive for anything but a sheet metal intake down low or any short runner intake. and ve table needs better transitions, i would start by choosing lower gears and revving it out slowly and higher loads to populate the ve table as much as possible. if you live at a higher elevation your timing map might be normal for your area as well.

I'm not sure if you looked at the datalog, but you'll notice that the IAT is functioning as it should.
The PE Spark Advance vs EQ table is retarding the timing by 5 degrees. Consequently, the total spark advance at WOT is 20 degrees. He should be able to add another degree or two safely.

[DB5249]

i didnt see log posted

[DB5249]

in the tune file he provided its already sitting at 24 degrees of timing at wot minus or plus whatever spark modifiers he is using, his timing map looks like a corvette timing map with slight modification to rpm ranger below 800, and low octane table does nothing since it is a mirror of the high.

[kevin87turbot]

in the tune file he provided its already sitting at 24 degrees of timing at wot minus or plus whatever spark modifiers he is using, his timing map looks like a corvette timing map with slight modification to rpm ranger below 800, and low octane table does nothing since it is a mirror of the high.

That's correct. However, he's using the PE Spark vs EQ ratio table to reduce the timing by 5 degrees. It's an odd way to do it, but the net result is around 20 degrees max timing at WOT.

[DB5249]

Attachment 120850 Give this a shot I am willing to bet your car wakes up a bit more (adjusted spark tables, burst knock, idol timing to give you a more aggressive sounding cam, iat timing safetys, i do not like that they desensitized your knock sensors but if it works it works.

[DB5249]

this timing curve is great for short runner intake cars with a good cam, it's aggressive down low some cars want more than this some less, just send a log after you dive it and I will help you dial it in.

[eXo3901]

Is there anything loose in the engine bay? I have had issues with PS lines, AC lines, and brake lines rattling around at the right RPMs. Does your steering wheel shake around 45-60mph? When was the last time the front wheels were balanced? How old are the front tires? Other than that, the initial timing transitions could be smoother and maybe PE needs to come in quicker above 2k rpms.

[Stroked06Goat]

I appreciate both your time in taking a look. Yes it indeed has an IAT. This was an old comb style LS2 maf stock. I added the MAF to make it NYS compliant, though do run in SD as i said, simply due to the erratic nature of the logs. It must be turbulent as heck in that short intake. I'd run the maf if felt i could effectively There is the IAT present and logging, and is mounted in the intake up front.

This has some pretty good chop at idle, and i had to adjust the VE substantially do reduce the richness at idle. Also played with the injection timing a bit based on a suggestion which did help the smell a bit.

Its my daily driver, and wanted to dial it in for driving it as such. But i also want to get it to the track and feel confident with safe spark numbers to keep it together. That spark that crops up here and there was the worry. Maybe not so much a worry but....on top it seems clean as a whistle.

Thanks DB i'll check out what you did. Honestly did not ever consider the IAT timing. how effectively do you use it typically?

[Stroked06Goat]

I thought about ramping in PE a bit quicker., i think i had it set to 1. Thanks EXO i honestly have considered that. Its so hard to tell as the motor spins up so fast but.... my header is VERY close to the steering rack. Typically on these they say elongate the rack for clearance, which i kind of assumed they did as the car came with the steering off considerably, but on a hard right i feel a bit of vibration and believe the header barely rubs that rack. Front tires do have a bit of shake and are up for replacement. Car has 58k on it now, and i've had since 45k.

[DB5249]

you use it to pull timing to prevent knock when iat gets high. i sent you a file and you can pull a comparison

[Stroked06Goat]

060722 New Spark Map.hpl

Gave it a go finally sorry for the delay. Short run on lunch but couple good pulls. Dont mind that idle ve, I am adjusting it. I was fighting a rich cold idle and went a bit too far with it. Anyway, spark...so i was looking at your burst knock retard changes and honestly, i've never dealt with any changes to such (what you saw in my tune is what its had the last decade).

So i witness more noise i guess you'd say? Minimal movement with knock but the top end looked pretty dang clean and ultimately running more spark 3-4* more than previously. Thoughts on KR you witness here?

Seemed peppy but again, this car seems to take off quick and it just started to rain so tough to tell. Try to baby the drag radials in the rain. Appreciate you thoughts!

[Stroked06Goat]

060722 pm New Spark Map.hpl Here is a longer ride from work. I guess, how much logged KR is ok? After all the reading i ever did....I just can't get a good handle on it.

[Alvin]

I reviewed your log. Your knock retard is really not an issue at all. It's very very light.

The only way to have absolutely zero knock is to have a car with bad knock sensors or a very very neutered tune. A degree here and there especially not consistent is 100% fine.