Smoothing Timing Map

[ninjai_ruken]

I can not for the life of me get this timing map smoothed out/cleaned up and it looks like utter dog shit! Any time I go to smooth or interpolate the transitions it seems like the truck wont pull as hard, like almost back to stock. Or everything gets WAY off. Still fighting with some knock issues and I'm 50/50 on it being false knock. I cant get it out of the back of my head that its not real Knock, I can get the knock sensors to kick off when I wrap on the long tubes. KR only happens at WOT or Hard acceleration. And when I pull timing out the the only cells that are detecting knock the knock retard shifts to other cells that did not show KR before. All I'm looking to do is clean this map up before I continue. This is after about 3 logs and subtracting timing. Any Advise on smoothing out a Timing Table when it gets to this point? The file with 1st at the end of the file name is the before, when I thought it was all just false knock. Maybe I'm just crazy and need to tell the little voice in the back of my head to tell me to STFU. Or maybe its just time to dump everything and start over fresh.

2000 Chevy Silverado 1500 4x4

Mods

BTR Stage 2 V2 Truck Cam
CC 918 Beehive Springs.
LT Headers/Off Road Y-Pipe/DynoMax Exhaust and Muffler.
K&N Intake/Filter

[kingtal0n]

For starters you would want to play with timing on a dynojet and not use seat of the pants feeling to determine good timing values.

It is likely the fastest setting is the one which feels "slower" due to the way the brain detects rate of change of acceleration and not rate of velocity increase so well,
In other words, if the timing map is terrible the vehicle will accelerate more sometimes than others, which will lead to the sensation that it is 'faster' but will show up on a dynojet curve as a wavy or spiky (bad) torque output, with higher peaks due to spikes and oscillations (bad).

whereas when the timing is correctly done the acceleration will be more gradual and smooth resulting with less feeling of acceleration, a smooth torque curve, overall lower peak power and torque due to smooth lines.

Your job as a tuner is to set the combustion pressure as low as possible for fuel and load safety while maintaining a satisfactory low EGT.
When using dynojet always set SMOOTHING = 0 In order to detect and diagnose perturbations of these nature

Next, Remember that Computer control timing can be quite different from mechanical advance. You are able to add timing and then remove it, and then add it back in. This technique is traditionally done to reduce peak combustion pressure through peak torque.

You would use the dynojet to find peak torque range and those are the lowest timing numbers through WOT after the "all in" breakpoint which is generally 2500 to 3000rpm.

Finally people will need to know (for timing help) additional info:
A. compression ratio
B. Vehicle use (does it see overdrive long wot periods or sustained WOT, how is it used, does it ever TOW a trailer? etc)
C. Vehicle weight
D. Desired fuel quality (does it use alcohol? gasoline? blend? Any boosters? Race fuels? etc...)
E. Intercooled? turbo? Nitrous?
F. How is the IAT? Where is the air intake breathing from, outside cool IAT or hot under the engine bay IAT?


Also in order to determine false knock from real knock you would want to set low timing (which knocks) and replace the regular fuel with race fuel, high octane fuel and see if the knock persists even with low timing.

[ninjai_ruken]

Thanks for replying, Some good information. I should have worded my initial post better, Running on little sleep. I am using a custom PID Formula based on generic MPH to log acceleration rate in my logs ([50020.114.avg(-1000)]) - ([50020.114.avg(1000)]) - Someone may want to check my formula to confirm its accurate. And I know you have to be really constant to make it work right. But I am able to see a change. Although not as effective as doing it on the dyno it does help. Ill try to post some logs in the next day or two, gotta lot of things going on with work as well as a bunch of work I'm trying to get done on my 97 Comp T/A.


Ill set the timing low and add some 100 Octane I have setting in the shop and see if it helps confirm false knock. Truck is a DD, Stock CR, No Towing, Running 93 Octane. IAT's have been logged both at 90 degrees as well as 58 degrees on the same ignition timing map all at operating temp before I started to make more changes and always seem to get KR in and around the same cells. I wish there was a way to compare logs like we can tunes. It would sure make it easier..lol

[kingtal0n]

Is that an LM7? 5.3L ?

I've done extensive testing with a 5.3L LM7, 862 head, at factory compression ratio and I can say with confidence that if it has clean combustion chambers and a full PCV system, that around 100% theoretical volumetric efficiency (about 300rwhp through a 4l80e) it will be safe with 19 to 21* btdc of timing.
I also tested it with 87 octane fuel and no trouble even using 4psi of boost pressure at 19* of timing, dynojet 330rwhp is safe (300lb-ft). (have dyno pic if you need)

I do not recommend squeezing the last couple of degrees out of it for the 10 to 20 extra torque and power because when things get hot or extended pulls are made or the environment is unfriendly, or when you are going uphill that one time with extra passenger or something, that couple of extra degrees can mean the difference between life and death for the engine parts, especially rod bearings which will not immediately show their contempt.

With around 15psi of boost pressure on 93 octane it needs around 11 to 12* of timing, so you can draw a pretty straight line from 15psi to 0psi and linearly adjust the timing curve this way (from say 19* to 11* as an extra atmosphere is added)

I can not open your file and didn't read it , these are just suggestions based on my own experience for the LM7 which I believe is roughly 9.5:1 compression.

My tune file is posted here if you want to see my timing table for LM7, 862 head, TFS30602001 camshaft
https://forum.hptuners.com/showthrea...l=1#post648378

* Keep in mind I Use "IAT Advance" and other modifiers to assist with timing retard for boost. I also kept burst knock feature intact among other unorthodox settings, so a severe overview is recommended since most of the settings I simply adjusted how I felt like doing it.

[ninjai_ruken]

Yup, LM7 5.3l Through a 4l60E. Ill take a look at yours as a point of reference. I never copy and paste other tune info directly into mine. I've been a mechanic for 15 years 5 of which working for a Professional Race Team. I know better as two identical motors 99.9% of the time wont have identical tunes. Maybe close but they always respond differently to different tweaks. Would make tuning way easier if it was that simple but also boring..lol

[kingtal0n]

In racing everything gets its own tune

In daily driving everything gets the same tune

It depends on the application whether or not you need the last 2 or 3% of power from an engine.
In racing with a level playing field you push the boundary of the engine and peak pressures to get 2 or 3% more power and win at the risk of the engine.

In daily driving you leave the last ounce of power on the table to avoid risking the engine.


In daily driving, all engines receive the same timing profiles to match their VE profile and combustion chamber dynamics given the set of inputs

Examples
A. Thousands of ROM tunes sold by local company "Tampa racing" for sr20det and 2jz-gte engines for the last 15~ years receive the same timing values without the owner ever seeing the majority of the engines or being specific to an any particular engine and resulting with thousands of happy customers because a general timing value is used which supports longevity while advanced combustion chamber design supports efficiency.
B. all of the Turbo LS engines in "sloppy mechanics" for examples, receive roughly similar timing values to match their VE curve, i.e. 11 to 13* of timing is standard across the board for 500 to 600rwhp LS engine setups regardless of any other variable using gasoline

General settings for performance engines "work" because the timing is a GENERAL setting, not an advanced racing setting.

Is it the best setting for max power? No of course not. You can always gain more by adding timing right up until the engine explodes or starting to work against itself.

But Pretending that fooling around with the timing in an NA application for a non-racing vehicle to find that specific threshold for one specific set of variables is a novice mistake which will lead to engine failure once those conditions change.

[leciphern]

Here's an SD tune I've been playing with since my BTR Stage 2 V2 install.

Maybe it can lend a hand?

I've been running 87 octane if that helps.

It's not finished because I need to install my wideband, but it seems to be road-worthy as my daily driver.

I've only touched a few things, Primary VE, Idle Adjustments, Abuse Mode edits, etc...

Just editing the VE table with my narrow-bands removed most of the KR I was getting on acceleration.

It was definitely there and there was no denying it.

[Matt Vardaman]

Here's one of my last few 93 octane tunes. Just so you'll have some files for comparison. Your timing is vastly differnt than mine. Pump gas only wanted around 20 degress or so at the top.7-22-21 Silverado trans shift adj.hpt

Here's the current Flex fuel tune. 10-19-21 2002 Tahoe Flex add spark to alcohol mod.hpt