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04 GTO Magnacharged, knock problems

 
Old 12-17-2018, 12:49 PM
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set the PE enable MAP lower to something like 55-65KPA and set the enable torque to 50%. set the enrichment ramp in rate to 2.0.
this should speed up the enrichment for acceleration adding the required fuel faster to match the additional airmass.

your spark table is quite aggressive for a PD car. I would be removing 3-4 degrees from 0.56g to 1.20g from 400Rpm up to 3600rpm. I would remove 1-2 degreed in the same area for 4000rpm and up.

typically a PD blower car is more susceptible to knock at lower RPM with rapid dynamic airflow change. personally I try to keep timing conservative in the sub 4000rpm transition areas where it traverses from moderate load to boosted areas. generally the 0.56g to 0.84g sections. keeping it conservative their avoids knock through the transition. PD blowers will take the spark at full load with RPM. they will take more spark as the air velocity increases with RPM. they wont take it down low where they go from cruise to full boost over one RPM column.
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Old 12-18-2018, 08:02 PM
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Originally Posted by Luke19901 View Post
set the PE enable MAP lower to something like 55-65KPA and set the enable torque to 50%. set the enrichment ramp in rate to 2.0.
this should speed up the enrichment for acceleration adding the required fuel faster to match the additional airmass.

your spark table is quite aggressive for a PD car. I would be removing 3-4 degrees from 0.56g to 1.20g from 400Rpm up to 3600rpm. I would remove 1-2 degreed in the same area for 4000rpm and up.

typically a PD blower car is more susceptible to knock at lower RPM with rapid dynamic airflow change. personally I try to keep timing conservative in the sub 4000rpm transition areas where it traverses from moderate load to boosted areas. generally the 0.56g to 0.84g sections. keeping it conservative their avoids knock through the transition. PD blowers will take the spark at full load with RPM. they will take more spark as the air velocity increases with RPM. they wont take it down low where they go from cruise to full boost over one RPM column.
Thanks for the suggestions. I will give this a try. I think it may be running a bit leaner because of the increasing percentages of ethanol in the fuel. This same tune has been in there since the day I got the blower installed. It's only in the last couple of years that I started noticing the knock. It may have been really close before they started diluting our gas, and now it's just enough to cause knock. The wideband is in the car now, but I have to pull the exhaust out to mount the sensor. Once I do that, I will reflash with the revisions and run some more logs.

The other question I have is on the Low Octane timing table. Currently, it appears to be the same as the High Octane timing table. Shouldn't it be lower in order to pull timing when knock is detected?

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Old 12-21-2018, 08:34 AM
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yes low should be less than high. personally I separate by 5*

that being said I normally make them the same for tuning and data logging
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Old 12-21-2018, 08:56 AM
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You have a 2 bar custom operating system? use the boost enrich map if so.

your timing is way too high. i cant use more than 14 degrees at 9psi with mine and 93 octane and very low IAT's. also on the last line of your timing table, lower the timing to 12-13 degrees. that will retard timing past 7psi.
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Old 12-21-2018, 09:41 AM
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Do you have a wideband your logging? i didnt see it in your scanner. very very helpful to have one.
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Old 12-31-2018, 01:36 PM
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I finally got the wideband installed on the car. I had Speedut make me a custom gauge/controller that matches with the rest of the gauges I already had. Of course, the backlighting is a bit too bright by comparison, but at least it works.


The sensor is just upstream of the factory pre-cat sensor on the passenger side. I'm inputting the data via the AC pressure sensor PID. Speedhut's installation instructions are skimpy (and they sent me the old version of the instructions).



The controller outputs 0-5 VDC. The problem I have is that there is no indication of how to convert the voltage output into AFR. I used the instructions from an AEM UEGO that I put on a friend's car. Their definition says AFR = (2.3750*voltage)+7.3125. That seems to be about 1-2% higher than what it should be at idle, so I massaged the formula a bit to (2.3750*voltage)+7.1125=AFR. I don't know if that is right or not?

Here's a screenshot of the pull in 3rd gear from this morning. It was about 50 degrees outside.



The log file is attached.

It does appear that the car is leaning out versus the commanded AFR. But, I need to figure out whether the scanner is picking up the correct AFR.
Attached Files
File Type: hpl
2018-12-31 log.hpl (633.3 KB, 4 views)
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Old 12-31-2018, 01:45 PM
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Originally Posted by Kfxguy View Post
You have a 2 bar custom operating system? use the boost enrich map if so.

your timing is way too high. i cant use more than 14 degrees at 9psi with mine and 93 octane and very low IAT's. also on the last line of your timing table, lower the timing to 12-13 degrees. that will retard timing past 7psi.
The tune is exactly what Magnacharger provided from new. It's a single-bar MAP tune and runs about 6 lbs of boost. I have a 2-bar converted version of the OS that I will eventually put on there. I was waiting on the wideband to be able to tune it. It would be nice to at least get the tune safe as-is before going after the 2-bar version.
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Old 01-01-2019, 08:18 AM
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where'd the MAF hZ in the log?
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Old 01-01-2019, 09:31 AM
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you have hp tuners, put a proper 2 bar map sensor in there!

and zero the burst knock table, it looks like as soo as your airflow delta picks up, you start getting more and more retard....dead giveaway
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Old 01-02-2019, 08:08 PM
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It looks like from the log and from driving the car while keeping an eye on the AFR that it's consistently running leaner than desired. In the screen shot I took, it's commanding an AFR of 11.35 and actually achieving 12.59 at 5,200 RPM. The EQ ratio for 5,200 RPM is 1.290 in the tune, so 14.6/1.290 = 11.32 commanded AFR. Do I increase the EQ ratio to force the car to run richer? Absent a 2-bar map tune, there really isn't any other way that I can see to richen the tune.

I'm going to pull some timing out and see what happens as well.

The 2-bar map is on order, but I'm still trying to sort out the original tune.
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Old 01-02-2019, 08:12 PM
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Well the easy way is to add more in the power enrichment (eq) but the correct way is to log the afr in a histogram and add what you need in your ve cells. Little trial and error. Real time tuning will help get it done much quicker.
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Old 01-02-2019, 08:25 PM
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No don't add more power enrichment. That's a hack way of doing it.

If you are running the stock 1 bar MAP sensor, you will will need to tune the MAF. You adjust your actual AFR to match your commanded AFR by adding more fuel into your MAF table.

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Old 01-02-2019, 09:09 PM
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Originally Posted by LilJayV10 View Post
No don't add more power enrichment. That's a hack way of doing it.

If you are running the stock 1 bar MAP sensor, you will will need to tune the MAF. You adjust your actual AFR to match your commanded AFR by adding more fuel into your MAF table.

its better to do it the hack way and be safer than to not do it and leave it lean. Before I really knew how to tune, I was doing it that way and it worked fine. Itís just my commanded afr was never correct. Which really isnít a big deal, but it is better to do it the correct way.
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Old 01-02-2019, 09:55 PM
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Originally Posted by Kfxguy View Post



its better to do it the hack way and be safer than to not do it and leave it lean. Before I really knew how to tune, I was doing it that way and it worked fine. Itís just my commanded afr was never correct. Which really isnít a big deal, but it is better to do it the correct way.

"IF" you know how to properly tune you would never even suggest the hack way.

OP,

Pull some timing out of it, 5 degrees or so, log MAF Hz, setup a AFR % error vs MAF Hz histogram(or whatever they call them now)
Find out what Hz you are at when you get into boost and add 15-18% from there on up to get your fueling closer/safer.

Personally I would ditch the AFR and tune in Lambda, it's much easier. But that is for another thread.
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Old 01-02-2019, 09:59 PM
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This reminds me of a 2000 Vette that came into the shop. Had a small Magnacharger on it. PE table was 1.510 which is like 9.6:1 on a gas scale. I guess that's how they use to do it before they learned how to tune.
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Old 01-02-2019, 11:27 PM
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Originally Posted by LilJayV10 View Post
This reminds me of a 2000 Vette that came into the shop. Had a small Magnacharger on it. PE table was 1.510 which is like 9.6:1 on a gas scale. I guess that's how they use to do it before they learned how to tune.
man you win! I didnít realize that you already knew how to tune perfectly on the first time you ever connected your computer to a car. My apologies that I had to learn on my own. One day I hope to be as great a tuner as you. I also hope that Iíd that day ever comes, that I wonít have the arrogance and smug attitude like you do though. Smh.


Op, to be clear, like I said previously, the quick way to do it (and like I said not the right way) is to simple add pe. That would get you in the safe region. I prefer (like I said, and I have to keep saying, like I said becausetgeres always that one person who feels compelled to jump in and correct someone) to set the eq ratio to the desired afr and tune the ve and maf to the correct afr to bring it all in line. But Iíll just let mr. Knowitall take over from here.


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Old 01-02-2019, 11:31 PM
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Originally Posted by Kfxguy View Post


man you win! I didnít realize that you already knew how to tune perfectly on the first time you ever connected your computer to a car. My apologies that I had to learn on my own. One day I hope to be as great a tuner as you. I also hope that Iíd that day ever comes, that I wonít have the arrogance and smug attitude like you do though. Smh.


Op, to be clear, like I said previously, the quick way to do it (and like I said not the right way) is to simple add pe. That would get you in the safe region. I prefer (like I said, and I have to keep saying, like I said becausetgeres always that one person who feels compelled to jump in and correct someone) to set the eq ratio to the desired afr and tune the ve and maf to the correct afr to bring it all in line. But Iíll just let mr. Knowitall take over from here.


Well that escalated quickly.

Damn man, cool your ****.

Crap. Let's get back to the OP so we don't trash his thread anymore.
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Old 01-03-2019, 04:49 PM
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Thanks for the advice on how to do it right (tuning on the MAF) versus using the EQ ratio. I knew the data for fueling had to be coming from somewhere. So if I understand this right, the MAF is supplying a reading of the airflow that is lower than the actual airflow. The computer fuels according to that reading, and the end result is the car runs lean.

The table to adjust is the MAF Airflow vs. Frequency table? Increasing the numbers there will tell the car that it's getting more air, which will make the computer add fuel.
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Old 01-03-2019, 06:17 PM
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Originally Posted by llafro View Post
Thanks for the advice on how to do it right (tuning on the MAF) versus using the EQ ratio. I knew the data for fueling had to be coming from somewhere. So if I understand this right, the MAF is supplying a reading of the airflow that is lower than the actual airflow. The computer fuels according to that reading, and the end result is the car runs lean.

The table to adjust is the MAF Airflow vs. Frequency table? Increasing the numbers there will tell the car that it's getting more air, which will make the computer add fuel.
Correct.

Make sure you pull timing out of it so you don't hurt it while you are doing your fueling.

Also what spark plugs are you using and what gap?
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Old 01-03-2019, 07:03 PM
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IIRC,, the original law that mandated E10, has a rising content requirement, I coulda sworn that 2018 mandated E15 and 2020 is E30 (Or something up that direction.) Need to go google it up see if I can find it..

Its the whole bio fuel fiasco thats got nothing to do with real emissions and everything to do with $$.. Sorry small soapbox popped up there..
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