Knock

[sikhabib]

when adjusting spark tables after the hisogram shows your getting knock is it best to adjust spark tables looking at the max value or just the average?

Also can someone please tell me what burst knock is

thanks
ronny

[Ls1GTO]

good question! I was wanting to know the same thing. Hope someone can answer this for us both.

I've been adjusting based off the average values, and making my changes in the high octane table only. I left the low octane table stock.

[JoeyGC5]

good question! I was wanting to know the same thing. Hope someone can answer this for us both.

I've been adjusting based off the average values, and making my changes in the high octane table only. I left the low octane table stock.

I did the same. Adjusted from average value in the high octane table. Then if needed adjusted the VE table to help out. However, I took the low octane table down by 2 degrees in some spots. Also had to make most of the air/fuel add table 0 to prevent extra timing.

[MNR-0]

This is what I do:

log mutliple runs/drives to determine where knock consistently appears
take max value
divide by 2
reduce spark by that amount
smooth surrounding cells
repeat

if there is no knock, i generally add 0.5* increments until knock occurs, then pull back 0.5* and thats it

[MNR-0]

This is what I do:

log mutliple runs/drives to determine where knock consistently appears
take max value
divide by 2
reduce spark by that amount
smooth surrounding cells
repeat

if there is no knock, i generally add 0.5* increments until knock occurs, then pull back 0.5* and thats it

And this is what my spark table looks like...

2d


3d

[narcszm]

A little too much smoothing, don't you think? The LS6 tune looks like the Rockies from the factory.

[brh26]

MNR-O,
That is one helluva spark table for a holden!
Any chance of seeing more of that tune?


Brian

[MNR-0]

A little too much smoothing, don't you think? The LS6 tune looks like the Rockies from the factory.

So did mine. But take some time to examine the max. spark vs rpm table and you will find with minimal smoothing it looks something like what I have.

Can't get smoother spark transitions than this, I reckon.

Ive examined many tunes and spark tables. Some gradually incline till 5200RPM and others are all over the place. It's tuning preference. Seems to me the spark table is largely dictated by the PE table at WOT and there is some curve similarity between the both.

Cars can generally take more spark before peak dynamic cyl/air, which occurs around 5200RPM on a stock LS1. This is why you see a peak at 3000 and decline till 5200 where there is a trough. After peak cyl/air you can add more timing, but not much, just to hold the power and get a flatter peak power curve for a few hundred more RPM.

I hold a consistent 12.2-12.6 AFR depending on which Dyno you use. Power runs have previously netted anything between 212-243rwkw. I dont trust Dynos. I reckon its more close to 225rwkw.

So, what else would you like to see? Dyno graphs? Other tables?

Consider my car is brother to the Pontiac GTO. Ive had 80+ track runs and best to date [email protected].

Mods:

HP Tune
25% underdriven pulley
shorty headers
2.25" dual exhaust (with cats left in original position under the firewall)
3.46 diff gears
added 2nd hole in stock CAI
modified TB so butterfly opens up 100%
gearbox rebuild (didnt need it)

and maintains:

stock 1800rpm torque converter
stock 75mm LT1 MAF

[brh26]

Hey MNR-O,
thanks for the info. Can we have a 3D plot of your VE table to admire?


Brian

[MNR-0]

Hey MNR-O,
thanks for the info. Can we have a 3D plot of your VE table to admire?


Brian

I haven't touched the VE table. Its completely stock. I dont plan on it either. I run a MAF, and it seems to own all VE calcs. even below 4000RPM. I dont ever plan on running MAFless.

I tried some ridiculous changes to the VE from 800-2000RPM resulting in not a scrap of difference to the fuel trims. So I leave it alone, and it leaves me alone. We have a healthy relationship, good ol VE and ME.

Sorry for hijacking your thread sikhabib, it wasn't intentional.

[mustbbrent]

I agree that the VE has NO IMPACT that I can tell. I have tried absurd numbers over 120 in a truck engine table that is stock. no effect. MAF seems to be the deciding factor. I decided to split the difference in the IFR and MAF tables as the IFR tables seem to help the MPG on the DIC and mine were off a bit. Besides, it looks good to be able to get 17MPG in an AWD 5400lb truck on the highway. Sorry to hi jack as well.

[Main_One]

I disagree about VE changing having no effect. I'm getting better launch from an idle due to having calibrated the VE table in my 5.3 truck's table.