Today made another WOT run on camaro, took her up to 100 mph and backed off. I am still getting knock retard during the run, and I been taking out some timing at the high load/rpm area. It doesnt seem to help. I have a graph of the run from TP RT. The knock retard goes up quick then staggers down slowly. I get about 5-6 deg of retard. The actual knock count goes from 16 before WOT, to 23, then to 27 by the end of the WOT run. I didnt think that this was very many counts. The spark advance rel to TDC stays fairly flat, and resembles what I have in the main advance table. The spark advance rel to ref pulse, goes up and down opposite of the knock retard. I think this is normal. For my main spark advance table, I dont have much timing, only like 24-25 deg at max load conditions. I have no PE mode spark advance. But what I found was 2 other tables having to do with PE Knock Retard.

One is PE Knock retard added vs RPM in PE mode, and another vs LV8 when NOT in PE mode. For the PE knock retard in PE mode, i have 6 deg retard from 4800 to 6400rpm. Is that what is causing my knock retard? How should these tables be used?
I know lots of folks usually run 34-36 deg at WOT. But my heads and cam are still stock L98 vintage, and i have read that these heads don't need much timing. Needs some help,

 

Here is my main spark advance table. Yea I know, sorry, just a copy and paste of the text, but I couldnt figure out how to save the table as an image in TunerPro. Any help?

RPM LV8
32 48 64 80 96 112 128 144 160 176 192 208
4800 40.08 40.08 40.08 40.08 40.08 40.08 37.27 34.10 30.94 26.02 25.66 24.61
4400 40.08 40.08 40.08 40.08 40.08 40.08 35.86 31.99 28.13 26.02 25.66 24.61
4000 40.08 40.08 40.08 40.08 40.08 40.08 35.16 29.88 26.02 26.02 23.55 23.20
3600 40.08 40.08 40.08 40.08 40.08 37.97 34.10 29.88 26.02 26.02 23.55 23.20
3200 35.86 35.86 35.86 35.86 35.86 28.48 28.48 28.83 26.02 24.26 23.55 23.55
2800 35.86 35.86 35.86 30.94 30.94 28.48 28.48 28.13 26.02 24.26 23.55 23.55
2400 35.86 35.86 35.86 30.94 30.94 35.86 35.16 28.13 26.02 22.15 23.55 24.96
2200 35.86 35.86 35.86 35.86 35.86 35.86 34.45 28.13 26.02 22.15 23.55 24.96
2000 35.86 35.86 35.86 35.86 35.86 34.81 33.40 29.88 26.02 22.15 23.55 24.61
1800 35.86 35.86 35.86 35.86 35.16 34.45 32.70 28.13 23.20 20.04 23.55 24.61
1600 35.86 35.86 35.86 34.45 33.75 33.05 29.88 26.02 23.20 20.04 23.55 24.61
1400 30.94 30.94 30.94 30.94 30.94 28.48 23.91 22.15 22.15 18.98 18.98 18.98
1200 29.88 29.88 29.88 29.88 27.07 22.15 18.98 17.93 17.93 16.17 16.17 16.17
1000 23.91 23.91 23.91 28.13 28.13 25.66 22.85 22.85 22.85 20.74 20.74 18.98
800 21.09 21.09 21.09 27.07 27.07 24.61 22.85 22.85 22.15 20.74 20.74 20.74
600 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04
400 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04

 

If pulling spark advance isn't correcting the knock issue then odds are it is false knock. I suggest you do a bunch of reading to get a better feel for what knock is and how the ECM handles it.

RBob.

 

MikeT: To take a screenshot, press the "print screen" button on your keyboard, and paste that image in paint and then save..
OPTIONAL (if you wish to crop out only a certain part of the pic): Select with the rectangle selector tool (on the sidebar) the part of the screenshot you wish to use, so now the part of the pic you want to use should be "selected", go to the menu "Edit" and then click "Copy". Then open the "File" menu and click "New". It should open up a whole new picture file and then just click the menu "Edit" and then "Paste" and it should paste the part of the pic you wanted in a new file. And if there is white space left over just simply go to the bottom right corner of the white space and drag that black square closer to the actual picture to get rid of all that useless white space.

 

Thanks for the tip, Wings. I was able to get a copy of my spark advance table. Check it out below. Just not sure what type of file to save as....there are many options. Looked like the jpeg came out a bit better than a GIF file.

Now if i can get some help on my spark knock......
BTW, i been taking some timing out, just maybe not enough. I go in small steps. Maybe need to be more agressive.
Just what does this table do, is it a "max" retard taken out in PE?
"PE Knock retard added vs RPM in PE mode"

 

To answer the question about JPEG vs GIF: JPEG (or JPG, same thing) is the better file to choose. It's smaller in file size than other file types yet maintains a high quality image.

About that table: I'm at work now, but from what it looks like, you can increase the maximum amount of knock retard that it can do when you're in PE mode.

Also, your table looks like it has a good amount of spark in the WOT LV8's... Doesn't look too high to me, but maybe there's not enough fuel being added up there? Do you have a WB02 to see the AFR?

 

Cool, JPG it is. I use them types alot. Here is my new spark table, and I just burned new chip and stuck it in ECM tonight. I took out some spark at high load/rpm area only. I think that one table is so that you can increase the max knock retard in PE at certain rpms, as compared to the fixed constant of maximum retard.
And also, yes, I have the LM1 WB meter in my car, and I got it setup to output the analog signal into the ECM datastream, so now I have that in my TP RT datalogs, with the other parameters. I just started getting serious with this (part)within the last year. For this last WOT run, the AFR was right around 12.0, or even richer than that. Way back, I had it in the 13s during WOT, so now I got it better. But I am still tweaking the AFR, and it seems like small changes in the commanded AFR tables are making a difference. So also, with this new chip I actually leaned it a tiny bit, just to get the AFRs closer to 12.5. Have to make a run this weekend and see what I got.
The other thing I am considering is that my knock sensor is going bad. I am quite sure it is original, so likely to be 23 years old. I priced a new one at AA for about 40$. Maybe next year!

 

correct on the max knock retard in and out of PE mode. When in PE mode you can limit how much timing is pulled during a knock event and at certain rpms.

You should NOT be having problems running 30-35 deg timing with those air fuel ratios. Stock L98s run 34-35 deg timing.

I got a feeling this is false knock.

Does it retard timing during cruise at all when your in the 35 deg range? What about a heavy throttle run but not WOT...say LV8 up in the 160-170's range?

Do you have a rattling exhaust? Does it hit anywhere on the frame/kmember? Noisy valvetrain?

Also check for accurate base timing vs whats in the bin. CHeck timing with EST connected at idle vs what the spark table is commanding. Everything should match.

That car must feel like a turd with only 20 deg timing at WOT!

 

I thought the low timing on the table at WOT levels (192 & 208 LV8) is because PE kicks in and ups the timing at WOT?

 

Good Q and A, Orr. Let's give you some numbers and keep going. You would think that a L98 could handle some good timing, but I have read a bit about it over the years, and most people seem to think these heads dont need much timing at all. My stock bin has numbers in the low 20s at high load. I hope it is false knock, but as long as I been tuning my chips, I have seen a little bit pulled during WOT every time.
There is NO retard anywhere else in my datalogs, only at WOT. I dont have any data at LV8 of 160-170, but that is a good idea to look at it then. Should be easy to get some there. All my WOT load numbers are usually well above 200 for LV8.
I think my exhaust is sound as well, but noisy valvetrain, sure I could buy that.
My base timing is set at 8deg, and it is same in dist w/o EST connected. I suppose I could still check that to confirm......checking timing at idle with laptop running is also good idea. Have to scrape the dust off the ole' timing light.

Lastly, no car does not feel like a "turd".....it runs great and pulls good. I haven't really seen much gain/loss from timing changes.....maybe I just need to make radical changes and test. Now as far as AFR, last fall I added a bit of fuel, to get the AFRs out of the 13s into the 12s, and that made a difference, IMO. Back in late May, I had 3 runs in the the 14.1xs, with 1.8-1.9 60' times. Then my MAF failed, and I spent all summer tuning that issue. I posted here a while ago on subject, long story, had the wrong MAF, tune was waaaay rich with that, finaly got the correct Bosch rebuilt unit in there, and got the tune real good. Now just working on WOT stuff.
Just running out of time, since I will be parking car soon, and the track I run only doing 1/8th mile runs, so screw that!
I just want to get into the 13s, and I think this car has it in it.

 

There is a seperate table that adds spark during PE, at a few different rpms. But that is adding that spark no matter what load you are at. Most folks just 0 that out, and use the main spark table for your WOT spark. That table is a large 2-D table, so you have lots of areas to work on. IE, not likely you will be at LV8 of 192 at 1000rpms.....so you can be smart about this table.

 

Makes sense.. But what I meant was that LV8 192 and 208 have low timing because MAYBE they took into consideration that PE was adding spark at those LV8's. This is just a hypothesis..

 

I got you now. In looking at my stock bin, at 192 & 208 LV8 at 4800 rpm, main table shows 23.2 deg, but in the WOT spark adder table, I have 8.1deg at 4800, so that would be 31.3 deg total advance.....so now I am really thinking about this

 

Yep

I dont like adding up the numbers from 2 seperate tables so I zero out PE mode advance and just work from one main table.

What bin you using as your base? I think mine had lower 20's in the high WOT load ranges, but it added 8 deg from PE mode to make it like 32 deg or so WOT. When I went to 34-35 the car seemed to pick up power. It only pulled 1-1.5 deg at WOT since it was abit lean and exhaust was noisey. I never tried it at lower timing but I can tell you this.

I ran my car one day at the track and dyno with EST disconnected... roughly 6 deg base timing. I dont know what that translates into at WOT or if it just stayed at 6 deg at WOT but the car went 14.0 at 94 mph and put down like 206whp. I plugged it back in and ran the car again with my timing which was in the 34 deg range. Ran 13.6's at 97-98 mph. Thats a significant difference there. So I'm kinda surprised your car seems to like lower 20's timing with NO PE mode adder.
Not all cars are alike and they may want different timing than normal 32-36 deg. But the simple reason you tried pulling timing out and it STILL pulls timing leads one to believe its all false knock. I'd be curious to see what would happen if you set it to 32-34 deg over what you have now and ran it at the track with 0 knock retard allowed. Dangerous since it could be detonating if its not false but just doesnt sound right to have a sbc running 20 deg at WOT

 

I am using an ARAP based bin. But definitely not the main spark bin from ARAP. I have put in alot of my settings from stock bin, and slowly tweaked alot of things over the years.
Today made another WOT run up to 100mph, with my main spark table set to 21.8deg at 192&208 LV8, at 4400 up. Below that timing was like 22deg. I got some spark retard during the run, but a little less than before. It made 4 retard attemps, first one was 4deg then 2,2,2deg. The thing is that the knock counts are NOT increasing much during the WOT run. eg, knock count was 4 before WOT, and 6 at end of it. so what does that tell me?
Also tried to get some medium LV8 numbers, but I ended up getting that just above 200, with TPS around 2.5v, and it still pulled a little bit of retard. I did it twice, and second time, LV8 was 202, retard was 6deg, and TPS at 2.62v. Knock count went from 7 to 8.

Yes, I am now thinking what you are thinking. Put in my main spark table, some higher values like what the stock bin has, adding the PE values to the main table. And of course I will have NO PE adder spark. I will likely leave in the knock retard allowed, no changes there. But I like having the option to take it out......
Interesting you ran your car with no EST.....I would think the dist would have some kind of advance built in....but maybe not. At least you proved that you needed the advance.
I wont likely get to a track this year, but I can make more changes and get some more WOT data....