WOT AFR & Timing Tuning

[blsnelling]

I kind of started this topic in the thread about getting my LC1 working, but want a thread dedicated to WOT AFR and timing tuning. Hopefully this thread will end up usedful to other newbies like the idle thread.

This run was mad on 93 octane fuel, from where I always buy it. There was no audible pinging at all. For those that haven't been following, I've already completed the CalcVE tune on my Main VE table and MAF table.

I'm most concerned with getting rid of the KR. Where do I start?



Looks like my WOT AFRs above 4,000 RPMs go from 12.30 to 12.86, getting richer as the RPMs climb. Isn't that on the safe side of a good tune, and can therefore be eliminate from being a cause of KR?

How about getting rid of that KR? How much KR does it take to hurt an engine? I know I'll be tuning it out, but just curious. Each WOT run in this log was different. One had nearly no KR, another maxed at 4, and then the last about 6. Is there a map you guys use to tune out KR?

Is the Spart High-Octane Table the one I'll be using to adjust WOT spark timing in order to reduce KR? What's the Base Spark in Gear table for?

Lots of questions. Take your pick:)

Log file
9358

.tun file
9359

[odd boy]

Looks like my WOT AFRs above 4,000 RPMs go from 12.30 to 12.86, getting richer as the RPMs climb. Isn't that on the safe side of a good tune, and can therefore be eliminate from being a cause of KR?


the AFR u mentioned should be fine.



How about getting rid of that KR? How much KR does it take to hurt an engine? I know I'll be tuning it out, but just curious. Each WOT run in this log was different. One had nearly no KR, another maxed at 4, and then the last about 6. Is there a map you guys use to tune out KR?

Is the Spart High-Octane Table the one I'll be using to adjust WOT spark timing in order to reduce KR? What's the Base Spark in Gear table for?

Lots of questions. Take your pick:)


you need first to confirm whether it reads from low or high octane table. Real KR will damage the engine even if it is 1 only. Sometimes, knock comes because of a lot of other reasons, like cat clogged, exhaust vibrates...etc

The car is reading from hi and lo octane tables as soon as you leave idle mode. KR increases if the value of IAT & ECT increases so u need to look at the timing temp tables to confirm enough retard at hi temp condition.

[joecar]

The pid ASPARK indicates the sliding-scale blend between the HO and LO spark tables.

+1 knock happens for many reasons and has many sources.

[DrkPhx]

- If you run 93 octane all of the time copy the High Octane Table to the Low Octane. Looking at your log and tune there is a 4 degrees difference at WOT between the two. The burst knock fast attack values are also set 4-5 degrees in the 4000 rpms columns and above. You can reduce them slightly as well.

- Your commanded AFR is 11.90-12.05 at WOT, but the WB reads 12.63 (on average) and hits 13.09 in some areas so you are at least 5% lean. If you want 12.63 at WOT, then set the PE to that value and tune accordingly. For sake of simplicity (and for sanity for now) set the PE values to one value for the majority of the table (example 2400 rpms and up). This will make it easier to tune WOT as you learn.

[blsnelling]

You mention that I'm running leaner than commanded. I'm afraid I'm maxing out my 8.1L truck injectors then. I did notice before that they're were up to 95% duty cycle.

[blsnelling]

I've copied high octane over low octane, since I will be always running premium grade fuel. I've also set B3618 to command 12.61 AFR in PE mode. Considering that I already have 6° of KR do you recommend pulling some timing in the high octane table? If so, I'm not sure what cells to mess with.

9377

[DrkPhx]

I've copied high octane over low octane, since I will be always running premium grade fuel. I've also set B3618 to command 12.61 AFR in PE mode. Considering that I already have 6° of KR do you recommend pulling some timing in the high octane table? If so, I'm not sure what cells to mess with.

9377

I didn't realize your injectors are maxed out. In that case don't even bother with WOT tuning and leave the WOT PE as is until you get new injectors.

[blsnelling]

That's what I was afraid of, lol. Time to upgrade the upgrades:)

[DrkPhx]

What psi are those injectors rated at? Do you have the stock fuel pump? I didn't look, but did you recalculate the Injector Flow Rate?

[WeathermanShawn]

Your PE EQ of 1.13 for E10 (see your B3601) is also quite lean.

For E10 you need to be closer to 1.16-1.17 (AFR 12.1). Your AFR's are tuned to the wrong fuel type..See:http://forum.efilive.com/showthread.php?11752-using-14.047-for-desired-AFR-and-not-14.63&p=103113&viewfull=1#post103113..E10 Worksheet (post#52).

[blsnelling]

Your PE EQ of 1.13 for E10 (see your B3601) is also quite lean.

For E10 you need to be closer to 1.16-1.17 (AFR 12.1). Your AFR's are tuned to the wrong fuel type..See:http://forum.efilive.com/showthread.php?11752-using-14.047-for-desired-AFR-and-not-14.63&p=103113&viewfull=1#post103113..E10 Worksheet (post#52).

Where are you getting the 1.13 from? I have B3601 set to 14.17, which is 9% alcohol on the chart you referenced. Are you suggesting I change B3618 to .855? If I understand this, I'm taking 14.17 * .855 = 12.115 PE commanded AFR?

[blsnelling]

I forget exactly what they are. I'm thinking they're something like 32# The 8.1L Marine injectors are 44#. That's what I'll be getting. My injector values where set by the tuner that I bought my initial mail order tune from.

[WeathermanShawn]

Where are you getting the 1.13 from? I have B3601 set to 14.17, which is 9% alcohol on the chart you referenced. Are you suggesting I change B3618 to .855? If I understand this, I'm taking 14.17 * .855 = 12.115 PE commanded AFR?

From your Tune.

B3618 should be in EQ for simplicity (not AFR!). An EQ of 1.16-1.165 will work for any fuel.
Yours is currently at 1.13 which is borderline lean, especially with the KR you are getting.

[blsnelling]

I didn't realize that could, or should be changed. For future newbies, I found it under Edit -> Properties, while the table is open. You'll have to close and reopen the tun file for it to take affect..

[blsnelling]

I've got a set of 8.1L marine 44# injectors on the way. Those should do real good for me. I suppose I'll have to go back and redo my VE and MAF tables. I'm guessing they'll be close, but should be gone over again.

It just so happens that my original tune was tuned by accident for 8.1 marine injectors. He later changed it to the 8.1 truck injectors that I have now. So I've got the values he was using for the bigger injectors. It looks like he changed B3701, B4001, B4003, and B4004. For B4001 he used 43.8374. My current injectors are only 29.9483!

[blsnelling]

Are you guys doing anything with B6244 to reduce knock sensitivity? My original tune had all 11s in the 0-1600 rows, and smaller changes in rows 2000-4000.

[WeathermanShawn]

I would strongly advise against changing any of the Knock Sensitivity Parameters like B6244. Mine is stock.

What I have modified is B6207 Knock retard Recovery Rate. Mine is at .2500. That way if and when I ever get KR (very rarely now) it will 'recover' back to the High-Octane Spark within 2-3 seconds..instead of the normal 8-10 seconds.

My preference for the street is to keep a 4-6 degrees range between High and low octane Spark. I like the ASpark feature. That way if you get KR, your spark reduces..you avoid the second-third occurrence. Everybody is different. But to answer your question I modify B6207 and perhaps B6203 by a couple of degrees.

[joecar]

I've been alot busy lately, but I have been reading along in this and the other thread, good info guys :cheers:

[etmotorsports]

I have noticed with the KR is that once it starts it goes a bit crazy with retarding timing, great if you have blower or nitrous but for NA kinda overkill. However if the fuel and timing is all correct most all but a small amount of the KR will go away i have only seen power numbers drop on the dyno when the KR is over 1.5 and up, most of the kr below that is all due to heat, which could really be an in audible knock and you should try to get rid of it. Some of the larger acamshafts and exhaust systems will set off.

[Sid447]

I would strongly advise against changing any of the Knock Sensitivity Parameters like B6244. Mine is stock.
What I have modified is B6207 Knock retard Recovery Rate. Mine is at .2500. That way if and when I ever get KR (very rarely now) it will 'recover' back to the High-Octane Spark within 2-3 seconds..instead of the normal 8-10 seconds.
My preference for the street is to keep a 4-6 degrees range between High and low octane Spark. I like the ASpark feature. That way if you get KR, your spark reduces..you avoid the second-third occurrence. Everybody is different. But to answer your question I modify B6207 and perhaps B6203 by a couple of degrees.

Agree,
Though for {B6244} I went through all the LS1 tune files I could find and used the "best" of them for most of the knock settings (usually found in the 2004-on files).

Best of them being, in no particular order:
2004 Pontiac GTO
2004 ZO6
2004 HSV GTS (SD file) [caution, the holdencrazy stock file has a few glitches in it or else it's not 100% stock].
2006 CV8 Z or HSV GTO

I also set {B6207} at .2500 from 2000rpm up.
{B6219} @ 1.0
{B6214 & 15} @ 300 & 6400rpm respectively.
{B6223} @ 2.0
{B6240,41 & 42} used 2006 VZ settings.
(Reasoning here is that by end of Gen 3 production the factory most probably had a handle on the right settings).

The only departure from some stock file is {B6210} :

LABELS Burst Knock Delta Air Mass (Grams)
RPM Value
0 0.500000
400 0.427978
800 0.373291
1200 0.336670
1600 0.310547
2000 0.288330
2400 0.268799
2800 0.251465
3200 0.236328
3600 0.222168
4000 0.208252
4400 0.195312
4800 0.182129
5200 0.167725
5600 0.151611
6000 0.135010
6400 0.119873
6800 0.103760
7200 0.085205
7600 0.061768
8000 0.034668

This works for me and I have had no problems of any kind. So please take as advisory only!