Gmt, I've been having some issues with the car not wanting any timing after my turbo swap. Do you think the optimum spark tables could have any effect on reducing this? I see kr on the logs, but I definitely don't hear or feel knock, even tried colder plugs and it showed exactly the same as my stockers.
Edit: Just saw a thread that was bumped from the stone age about clocking the knock sensors, I knew this had been addressed, but was unsure of it, might have to give it a try.
Last edited by Ch1ck3n; 07-08-2012 at 01:16 PM.
Post up a log if you want. LNF's have what I think is the cr@ppiest knock control system I've ever seen in an ECM. In an E38, if you see 1.7 degrees KR in a certain cell, lower that cell's timing 1.7 degrees and the KR will be gone. False knock is almost never a problem in other ECM's, in the E69 there's more false knock than real knock! Fuel mixtures will absolutely cause KR. Here's what I tell guys that have a bunch of KR in their logs- advance the ign timing and lean out the mixtures. Really! That's absolutely horrible advice on any other motor, but on the LNF it's usually what needs to be done. I say advance the timing because most guys have retarded it so badly trying to stop the KR, and it's not actually caused by the timing. If you advance it, and it is from timing, you'll see the KR go up, which will tell you something.Originally Posted by Ch1ck3n
Don't tell anyone, but I haven't used ANY knock control in my LNF in a very long time! I trust my ign timing and tuning, I don't need a cr@ppy knock control system screwing with my timing. Remember, we "old timers" tuned engines without the aid of knock control for many, many, many years. It it's a good system, knock control is awesome. If it works like cr@p, don't use it. (DON'T TRY THIS UNLESS YOU'RE FULLY AWARE OF WHAT YOU ARE DOING.)
Link ecu knock block is the shit
2000 Ford Mustang - Top Sportsman
Idle is alot smother now ill post up a log when I get home, gmtech do you have any screenshots of wot and decel with your new tables, just wanna see what your timing curve is like compared to mine.
I've been considering doing this as well, I'm by no means an "old timer" but I definitely know what knock sounds and feels like, just have been a bit afraid of killing off the knock tables altogether. I 0'd out the load dynamics kr to no avail. It's 114* outside today, so maybe I'll go out a bit later and see if I can get a good solid log.
Increasing timing and leaning afr's only seemed to make it more sensitive, maybe It's real and my butt knock sensors are just not sensitive enough to notice it.
Many years ago I built a pretty stout 360 Dodge in our little Class C motorhome, I used this http://www.msdignition.com/Products/...ock_Alert.aspx
to monitor knock from the high compression pistons I had in it, and this
http://www.msdignition.com/Products/...g_Control.aspx
to control the ign timing. Worked awesome! Before that I had to set the ign timing for the worst fuel at the worst altitude and heat conditions, which would end up being about TDC on that motor. With the knock sensor and adjustable timing control I was able to get a whopping (lol) 15 degrees advance, which did actually make a huge difference in power and mileage. Pretty high tech for the '80's.
I will never forget when my dad first taught me about knock by having me put my ear to the engine cover on an old Ford Econoline van. He said it will sound like "milk bottles rattling". Who even knows that milk used to come in bottles?! I heard it and though it was so cool! BTW, anyone ever hear knock in a small motor like in a dirtbike? It sounds really weird, super light and tinny sounding.
Last edited by gmtech16450yz; 07-08-2012 at 02:04 PM.
If only things were that simple nowadays. Now we have spark tables for 4 different piston positions and lookup tables, variable camshafts, desired airloads and maf calibrations, lambda efficiency tables, haha the list goes on.
So I'm still getting some mixed results from these tables ESPECIALLY at WOT. I tried seeing what effects increasing the areas mainly from 3k-redline at wot would have without making too many other changes to other tables that could skew results, such as DAL's and cam. So far I'm really not sure what to make of it. It seems as though if I go just a couple "clicks" too high in the high load areas it seems as though I'm losing a bunch of airflow, airload, and airmass (obviously I'm sure they're all related). It's also noticed in my injector pulse widths (however not by a huge difference though). At 6500rpm in the log where I have more airmass I'm seeing a 5.5m/s pw, and in the log with less airmass at the same rpm I'm seeing a 5.4m/s pw. Granted I know it's not much but I'm just looking at all the areas that are different.
So anyways, here are a couple of screen shots to show what I'm talking about. First is of where I raise the wot areas relatively substantially, and saw a decent gain in flow.
[IMG][/IMG]
This next one is basically the same tune file, aside from slightly higher values in the WOT areas. Notice the relatively drastic drop in airflow between the 2 logs?
[IMG][/IMG]
One last thing I noticed while making these changes is that it seems to throw the trims off a decent amount. I'm not sure if it's just my evap purge solonoid throwing things off on me or not, but again, it's just something I noticed in the logs.
I'm curious to see what results anyone else who is tweaking these tables has come up with just as something to compare my findings to. I don't know, maybe I'm just missing something here. Let me know what you guys think. Thanks..
09 Cobalt SS - E47+EFR6758 =
07 Silverado ECSB LBZ Duramax - Bunches of goodies
heres how mines looking now still messing with it a little
before
after
sitting at 20 now, just needs smoothed out!
just a thought, maybe your timing is set to high in the two tables, and when it is seeing that it is getting the requested goal fr timing it is not thining that it needs as much airflow, then it drops the arload level. Or it is set to low and it has acheved what you have it set at and the airload drops because its goal is attained.So I'm still getting some mixed results from these tables ESPECIALLY at WOT. I tried seeing what effects increasing the areas mainly from 3k-redline at wot would have without making too many other changes to other tables that could skew results, such as DAL's and cam. So far I'm really not sure what to make of it. It seems as though if I go just a couple "clicks" too high in the high load areas it seems as though I'm losing a bunch of airflow, airload, and airmass (obviously I'm sure they're all related). It's also noticed in my injector pulse widths (however not by a huge difference though). At 6500rpm in the log where I have more airmass I'm seeing a 5.5m/s pw, and in the log with less airmass at the same rpm I'm seeing a 5.4m/s pw. Granted I know it's not much but I'm just looking at all the areas that are different.
So anyways, here are a couple of screen shots to show what I'm talking about. First is of where I raise the wot areas relatively substantially, and saw a decent gain in flow.
This next one is basically the same tune file, aside from slightly higher values in the WOT areas. Notice the relatively drastic drop in airflow between the 2 logs?
One last thing I noticed while making these changes is that it seems to throw the trims off a decent amount. I'm not sure if it's just my evap purge solonoid throwing things off on me or not, but again, it's just something I noticed in the logs.
I'm curious to see what results anyone else who is tweaking these tables has come up with just as something to compare my findings to. I don't know, maybe I'm just missing something here. Let me know what you guys think. Thanks..
^^Yeah I had mine nice and smooth for a while there but now I'm noticing a decent fluctuation in the timing and trims when coming out of open loop. Mine's actually a little worse than yours though to be honest, although your trims look to be holding better than mine. I did make some drastic changes in a couple other tables in the idle areas so that's probably where I went wrong. It's really just trial and error at this point (for me at least) so I was just sort of testing the waters here.
I thought about maybe raising my idle a bit to the 1050 or so like you have yours, but I don't really feel as though that's the correct solution. I had it smooth as glass at 950 so I'm going to go back to where I had things before and see if that smooths it back out again.
:edit: You replied to my post before I posted this.. lol
I did also try lowering the values in the wot areas back down to where I previously had them as well so I'll see if that fixed things for me tomorrow if I can. What's weird is it was only a difference of a matter of value of 5. Apparently it was 5 too many though.. lol
Last edited by Freakotec; 07-08-2012 at 09:59 PM.
09 Cobalt SS - E47+EFR6758 =
07 Silverado ECSB LBZ Duramax - Bunches of goodies
These table are used for torque calculations. I'm not positive here, but I wouldn't be surprised if they effect VE Airflow numbers. I tell guys all the time- DON'T TUNE BY LOOKING AT AIRFLOW NUMBERS. Especially MAF airflow numbers, since they can be skewed by huge percentages when you change MAF calibrations in the tune. As much as the Engineer thinking guys like to think, X amount of airflow DOES NOT equal X amount of power. Honestly, 60-100 times or consistent dyno runs are the best way to judge power increases. You just can't judge power changes by airflow when you're changing things in the tune that effect airflow calculations.
Keep working on it guys, you're learning!!! Isn't it fun? I'm really sorry I didn't post up this info on these tables a year ago.
Like I've said before, the idle stuff is a delicate balance between ign timing, throttle position and fuel mixtures. They all have to be within a certain range to work together happily. The sweet spot for LNF idle ign timing is between 15 and 20 degrees.
Yeah im going to mess with wot a little bit tonight or tomorrow, pm me your file or a screenshot of your tables and we can compare if you want. Still dont know how gmtech got his so smooth yet! Im going to continue just making small changes at a time, right now my wot timing is where i have it commanded so idk what im going to do with that yet. Just going to make a few small changes and go on it took me 13 different files to get that idle!
Have you guys with the fluctuations made changes to all tables? I'm not sure how everyone has their spark timing set up, but if all your spark timing tables are the same (which is how I've come to tune my spark advance) and the optimum spark tables are different, theoretically it would cause the ecm to start jumping around trying to find the right spark timing for its calculations from the lookup table..
Any thoughts?
Edit: Also, GMT, how do you recommend setting up your spark timing axis labels? I have them scaled right now to 300% air load and 7000rpm.. Is it better to just leave those alone and tune just the far right column for WOT? The tables are so limited in how much adjustment you can make between cells, I'm starting to think as if it would be better to just scale one column for WOT and the rest for cruising, driveability and throttle response..
Last edited by Ch1ck3n; 07-09-2012 at 12:16 PM.
I have always tried to stay away from making any changes to the maf frequency table. If you look at it it basically resembles a compressor map for the lnf stock turbo. If you raise it too high then your telling the engine its getting more airflow than it actually is. This is when I saw my bit of timing droops. Makes sense now sorta. It thinks it is making the desired torque from boost rather than ignition.I pmd you a while back on this and was going to get into detail with it but never got a reply. My theory is that this table should not be adjusted unless the diameter of the maf housing is enlarged or you put a bigger turbo on the car. Global changes to the fueling should be made in the injector constant. The frequency table could then be adjusted with a equation based on how much larger you go over stock.
HP-Unlimited Tuning and Custom Fabrication
Houston area performance parts dealer
MD800 Mustang Dyno 713-560-3889 Taylor
2016 Camaro A8 "shop car" FIRST 6th GEN CAMARO OVER 200mph IN THE MILE 203.5mph
Sorry about the PM thing, I'm not very good at replying to those! I usually read them because I get the email saying I've gotten a PM, but I forget to actually log in and reply to them. I also figure if I'm gonna take the time to write something out about this stuff, it might as well be in public so the lurkers can see it too. I know there's a bunch of guys reading this stuff that never post or PM, they just silently take it all in. Nothing wrong with that I guess, but again that's why I usually answer online instead of in PM's.
There's nothing wrong with tweaking the MAF tables, but yes, you're partially correct in that the frequency table "usually" doesn't take a whole bunch of non-linear changes. I actually do a combination of injector constant AND MAF frequency to compensate for E47 or E85. The other MAF table, the correction table is also very important, and again, there's nothing wrong with changing values in those cells. You just have to realize that the MAF airflow numbers will not be accurate as far as judging power.
Speaking of MAF calibrations, and whether you should keep them as close as stock as possible, guess what? The stock MAF calibration is pretty darn skewed anyway! All MAF's have a frequency lookup of some sort, there's no way any MAF wouldn't need some sort of calibration modifications, even in a bone stock tune from the factory. What you ideally want is your VE airflow and your MAF airflow's to be close to the same. That means what the MAF is seeing is also what the Speed Density calculations are figuring airflow is. That makes them, and all the other tables happy when there's not a whole lot of difference between the two. Everyone is so used to seeing MAF airflow about 10lbs/min over what the VE airflow is reading, even on a stock LNF. That's not really normal or even ideal. Whether you're tuning Speed Density or MAF, you want them to be somewhat close to each other, that's the whole point. BTW, I'm running a blow-through MAF and my MAF frequency and correction tables are LESS skewed than stock (except for the 5th injector changes of course). That in itself is proving that a blow-through MAF reads MORE accurately than the stock one that's about 12 feet of tubing, an intercooler and turbo in front of the actual engine.
As far as the ECM making adjustments from airflow or ign timing calculations, they all have to be within a certain range, just like I've said about idle tuning. Up until now, all LNF tuners have been tuning by only making changes to airflow calculations. With these Optimum Spark tables, you're also able to control the ign timing calculations, and the airflow changes that come from it. Like I said before, anyone that says LNF tuning is a piece of cake and there's only a couple tables that really do anything, they don't know chit. I have a clue about how these tables work, but I'm not positive on a lot of this stuff. The ONLY guys that are positive on E69 tables are the guys at Bosch that came up with them in the first place. I even know the GM guys are pretty much clueless on the LNF E69, I've seen tunes from GM Racing that were pretty rough!
Last edited by gmtech16450yz; 07-09-2012 at 04:03 PM.
still cant get this idle smoothed out! It will looke beautiful for a few seconds then get choppy, then good, then awful. RPMs are fluxuating a little bit, but im thinking there might be something to do with cam tables. Ill attach two logs. First is what i had it at day 1 and second is what it is at today.
It's not looking that bad, you've already got a better cold start than 90% of the LNF's out there! Try lowering your desired idle speed, it might be a bit high.
You're very close, the airflow and the timing are still just fighting each other a little bit. When the timing goes high, it means that there's not enough airflow to keep it at the desired idle speed. When the timing goes low, it's the opposite. Same relationship with the throttle, when it goes higher, it means there's not enough ign timing to maintain the desired idle speed. (More ign advance will raise idle speeds quite a bit.) If you lower your desired idle speed, hopefully the throttle position will steady out a little lower and the ign timing won't have to try to go up so high at times.
Don't give up, you're getting it! Like I said before, you know how many LNF tuners have fought to get idle ign timing like that? Tons.
Yeah im going to mess with it again tonight. This makes perfect sense though because it sounds like the motor doesnt know that it wants!
