What is the purpose of the The PE/COT Spark Advance Correction table? Would I be better zeroing out this table and putting the timing in my main spark table?
What is the purpose of the The PE/COT Spark Advance Correction table? Would I be better zeroing out this table and putting the timing in my main spark table?
Post your file then we can try to help.
Yes, it would ultimately be best for you to dial in the main spark table, and dtich the PE adder table.Originally Posted by bonaprp
What is the purpose of the The PE/COT Spark Advance Correction table? Would I be better zeroing out this table and putting the timing in my main spark table?
No. I completely disagree.
The PE/COT table has a very good purpose: Altering Main spark advance when PE is ON and not until PE is ON.
An engine that is at 14.7 AFR can not tolerate as much timing as an engine running 12.8 AFR.
If you are at the same airflow level but the engine is tuned for max spark at 12.8 AFR and you are NOT in PE thus running in closed loop (14.7 AFR), you will get too much spark and consequently KR.
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Having the spark in both the PE table and the main table would this change the rate in which spark is added when compared with having it all in a single table ?
INTHERED
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The PE/COT table spark applies as soon as PE is entered.
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I'm not sure how one could have the same aircharge at part throttle as they could at WOT, hehe. Trust me, I agree with what you're saying here in regards to fueling and spark tolerance. That's simple physics. However, for a given aircharge and fueling (both afr and octane), there is *always* a proper amount of spark that should be utilized, all without inducing detonation. It is not difficult at all to tune the main spark table so that the proper amount of spark is given for such specific aircharge and fueling, without the need for utilizing the PE Spark Correction. Obviously, it is also crucial to set the PE Enable TPS table properly, as well. Most all of GM's performance vehicles already have very good values in the "PE Enable TPS" parameter, however.
GM never used PE Spark Correction on the '98-02 F-body, '98-'00 Vette, '01-'04 Z06, nor the '04 GTO (the table is just zeroed out on all of these vehicles). This isn't to say that I always zero out the PE Spark Correction on every GM vehicle I tune that utilizes such already. Either method can and will work. However, in regards to GM's performance vehicles (like the ones I just mentioned), I personally prefer to remove the potential parameter variables. (With that being said, I'm curious to know if you actually utilize the PE Spark Correction on the aforementioned vehicles, even when GM doesn't?)
GM calibators have never been consistent on their tuning methods for their vehicles. There are tons of GM vehicles with a raped PE table from the factory, and tons of other GM vehicles that do and don't have the PE Spark Correction utilized (Ford also has the same parameter [PE Spark Correction] in their vehicles, and at times does and doesn't utilize it). It is apparent that some of their calibrators are lazy, and use these parameters as quick fixes, instead of properly dialing in the MAF transfer, and/or spark settings, and even COT in some cases.
Everyone, something else that should be of concern for some is when they are out of MAF range, and are then using the PE table to keep fueling in check. If they aren't watching what they are doing, they could easily have way too much spark being commanded, in both the main spark table, and the PE Spark Correction table. When a MAF is out of range, the pcm is not able to calculate Load (aka aircharge, aka cylinder airmass), thus reported Load drops, and spark may increase in relation to such. This is especially true if they haven't modified GM's factory values, since generally GM sets the PE Spark Correction to add in a lot of spark for a richer commanded PE. Yet another reason to take out the potential variables.
Sincerely,
James
Last edited by RWTD; 07-07-2007 at 11:31 PM.
I was thinking that there was something up with that today when I was doing some tuning work on a friend of mine's LS2 GTO. When I went to the High Octane table to add some more timing to the car; no matter what cell <cylinder airmass> I altered, the car did not react to the changes the way I expected it too. Right now I have the car set at 27 degrees advanced, but yet when I log in third gear, the car only achieves 25 degrees-and with almost zero knock. I have heard you can run as much as 28 to 29 degrees, but I don't want to mess around with the timing tables any more until I find out what other factors GM has that influences timing-and this could very well be the PE/COT table.
Suggestions would be much appreciated.
Later,
Vincent.
2011 Ford Mustang V6 Six Speed
James,
No prob...
I envisioned some areas where there could be some overlap of PE vs No PE based on other variables than the basics. eg. high altitude vs low altitude.
I have run the cars with COT/PE zeroed (and tuned accordingly) and with the values populated and I have always found that the cars perform better (strictly with the GEN IV's here...) and more consistently with the table populated both on the dyno and street/track. Don't know exactly why though. Maybe we're missing something when it's not populated?
I also agree with you about running out of MAF. A huge problem in the GM world, not encountered (or encountered but easily fixed) in the Ford world. LOL Looks like the `08 Vette will give us some hope though!
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Vincent,
You're definitely experiecing the PE Spark Correction, especially since it sounds like you haven't adjusted it. This factory GTO parameter actually starts removing spark at 6k and above (via interpolation), but only -0.5 by 6400, and then -1.0 by 6800. This may not be the only correction you're experiencing, so check IAT Correction, too!
As for running as high as 28+ degrees, careful there, the LS6 heads do not necessarily care for a lot more spark than factory (an '01-'04 Z06 is a prime example of this), and you may find too many instances of KR. Also, keep in mind, and I know this sounds crazy, but just because you're able to add more spark without the knock sensors measuring knock, doesn't actually mean you're gaining more power.
Regards,
James
^^^^ Amen to that! BTDT & GTLTS...
In fact many of the LS2's I have tuned like less timing than factory stock not more. GM seems to be rather aggressive on the LS2's with timing.
Some of your timing needs are based on the exhaust system as well. I had more than one car that wanted much less fuel and less timing because the exhaust system just would not transfer.
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So your saying when you tune an LS2 WOT to 12.8-13.0 AFR from the stock 12.4-12.8 AFR, you pull timing out? How much? Is there a general rule of thumb? Will the LS2 make more power under the curve running leaner with less timing than fatter with more timing? I can't imagine that it would. I have thrown more and more fuel to mine and it picks up. There is a point though where I can't quench timing with more fuel though.
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I've never seen one do 12.8 to 12.4 stock. On average, they are too lean down low, about right in the mid-rage, and way too rich up top. A factory LS2 GTO is set to 12.04 afr from 5k on up (the LS2 Vettes are about the same up top). It's even worse when COT kicks in.
When I dyno tune, I tune from at least 1500 rpms, sometimes less, even with automatics (I just lock it in 3rd for the A4, or necessary gear [3rd or 4th for the A6, depending], and lock up the converter).
Regards,
James
Last edited by RWTD; 07-09-2007 at 03:06 PM.
Well this guy actually has some pretty decent mods on his car. He has the Kooks Long Tube headers, X-pipe, and Borla mufflers, along with a K&N FIPK kit and a set of Nitto 555R's. He was running on a canned Diablo tune before which was there "off road" tune. He was complaining because the car was getting horrible gas mileage, 15 mpg(trying to conserve fuel), and he felt like the car wasn't pulling like it should. When I got through with just changing the PE table and taking away the shitty GM torque management, he said it felt like he was driving a new car.
I still have alot to learn on this stuff, and I definately need to get his car on a dyno and check the fuel to see if it's right. I just used a PE table that was tuned with an LC-2 from an 05 GTO that was in the Tuner files on the HP Tuners website. But from what I can tell, the fuel is pretty close. Even after getting a couple more degrees of timing into the car, I was only getting .5 of KR. I am looking over his tune now, and your right-the car is set up to pull out as much as 6 degrees of timing based on IAT temps. Is it safe to remove this and just rely on the High/Low octane tables?
Thanks for the help James, I have talked with you before on the phone about tuning my Cobalt SS Supercharged before a while back, when I used to live in the Mobile area. Hope things are going well for you guys. Maybe you can give me some pointers on tuning the Cobalt...lol. I have been working on it for a while with the help of a friend of mine who is alot more knowledgeable than me about HP Tuners and it seems to work. Any advice you have to give is greatly appreciated. You are definately the king of factory blower cars.
Thanks again,
Vincent.
2011 Ford Mustang V6 Six Speed
Also, does anyone have a good config file for GTO's? If so, could they e-mail it to me at [email protected]?
Thanks!
Vincent.
2011 Ford Mustang V6 Six Speed
Bump!
2011 Ford Mustang V6 Six Speed
This must suck for people who up the pe table and set the timing lower to run a little n2o.
This table is 0'd out in some (if not all) ls1 files I have seen. Is it usable? When the pe is delayed, is added spark blended? Does it have a tendency to prefer the lower or higher value when "interpolating"? For example... if the eq ratio is 1.172 and the spark adder value for 1.15 is 1.0 deg and 1.20 is is 4.0 deg. Notice I said 1.172 eq ratio.. Does it go with 2.5 or 3.0?
Sorry if that doesnt make too much sense im on a phone..
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I worked it out to 2.32 as the interpolated value.
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