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Do I need to pull some timing?

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Old Apr 12, 2012 | 02:19 PM
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Default Do I need to pull some timing?

Please have a look at my log and tell me if I need to pull timing or not. I am just getting my tune dialed in and am noticing a slight KR. The histogram only shows 1's showing up in a few cells. When I look at the chart display where it is pulling timing (frames 2986 through 3012) KR stays under 2 but I see total timing drop as much as 4 degrees. Does that have to deal with burst KR? Do I need to back some timing out? If so just 1 degree where it shows up in the hystogram?

If anyone has any overall opinions or advice on the tune I am willing to listen to that too. This is my first time tuning. 06 GTO single T70 turbo at 6psi. Still in open loop (no O2's active) mode and VE tuning.
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Old Apr 12, 2012 | 04:54 PM
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if that wideband reading is right (stock 02 mv shows rich also) you need to pull some fuel
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Old Apr 12, 2012 | 06:30 PM
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Originally Posted by bad6as
if that wideband reading is right (stock 02 mv shows rich also) you need to pull some fuel
I am still working on that. This is my first go at turbocharging a car and tuning it myself. So I am trying to be safe as possible. I just fired it up no more than a week ago and have been tuning on my 15 minute drive into work and back. As I continue to lean it out you think that will go away? I just looked over some other logs and it does not seem to be a constant thing. Some pulls look smooth with the advance.
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Old Apr 12, 2012 | 07:10 PM
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Originally Posted by bad6as
if that wideband reading is right (stock 02 mv shows rich also) you need to pull some fuel
Not sure if you looked at the waveform at all on the O2s, but they only seem to cycle when he gets on it. I would def look at that afr first and why your O2s are not registering right. Get those tamed down and you wont have strange jumps in your Duty Cycle like you see right before the knock happens on that 2nd wot. There is more that needs to be dialed in that is contaminating the WOT signal also it seems.
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Old Apr 12, 2012 | 09:06 PM
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Originally Posted by gectek
Not sure if you looked at the waveform at all on the O2s, but they only seem to cycle when he gets on it. I would def look at that afr first and why your O2s are not registering right. Get those tamed down and you wont have strange jumps in your Duty Cycle like you see right before the knock happens on that 2nd wot. There is more that needs to be dialed in that is contaminating the WOT signal also it seems.
There is no wave form on the narrowband O2's because I have it forced in Open Loop for VE tuning. Once I allow it to go back into closed loop you will see the narrow bands begin to cycle again.

I am thinking about putting it back into closed loop because I am pretty happy with my main VE table. Can I still tune my boost VE table if I put the car back into closed loop or is it better to leave it in open loop?
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Old Apr 12, 2012 | 09:08 PM
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You can tune the boost PE running in closed loop because when you enter the PE, it is open loop anyway. So not big deal there.
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Old Apr 12, 2012 | 09:35 PM
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Originally Posted by gectek
You can tune the boost PE running in closed loop because when you enter the PE, it is open loop anyway. So not big deal there.
Cool thanks! I figured that was the case but I wanted to be sure. Did what i say about the narrowbands make sence or am i missing something?
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Old Apr 12, 2012 | 09:41 PM
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The narrowbands do not make sense, then when you hit it they register. Looks like from the Wideband, they are in range for a bit and it starts to read again.

I tuned a truck one time and at WOT the fuel trims would still read like what you are seeing because the wideband told me the afr was 13.8-14.8. So of course they will switch then. I would watch that and make sure it transitions better than that. It looks pretty strange.
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Old Apr 13, 2012 | 09:21 AM
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Default New Scan.

Originally Posted by gectek
The narrowbands do not make sense, then when you hit it they register. Looks like from the Wideband, they are in range for a bit and it starts to read again.

I tuned a truck one time and at WOT the fuel trims would still read like what you are seeing because the wideband told me the afr was 13.8-14.8. So of course they will switch then. I would watch that and make sure it transitions better than that. It looks pretty strange.
Here is this mornings tune log. I put it back into closed loop and reloaded my old boost ve table that produced no KR. This time I have no KR. How do the narrow bands look in this one? Main VE is the same from the other tune. I am going to fatten up a couple spots in my boost VE tabe that look like they need it. The lean spot is not the cells that see a lot of hits, they are more transition cells.

Here is another question. I have high command for fuel as i get into boost and it produces the need or a big spike in the boost VE table around 110 to 114 kpa. Although I cant seem to get rid of it with upping those cells. I tried to lower my map boost enrichment to 95kpa from 105. t didnt seem to help. I think I read someting about modifing the transient fuel impact factor. I played with the gas table at the 100kpa area to raise some value but I am afraid to change it too much without fully understanding what I doing. I think I get it but the little change I made did seem to make a difference. I have looked at every 2 bar SD tune I have been able to get my hands on to see if those table have been modified and no luck. The tabels either look like mine or one other similar patter which I assume is an LS1 tune and mine is an LS2.
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Old Apr 13, 2012 | 08:00 PM
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Looks good. Fuel trims ned a tad bit of work. Also you can see when you are cruising or slowly accel that your timing is jumping around a bit. I would smooth those areas out. You may also want to look at your spark table for the wot shifting. That I believe is part of min spark advance or something like that. Then it wont drop off so bad and then immediately spike back up. Sometimes that can cause knock from the high transition.
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Old Apr 14, 2012 | 04:07 PM
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Thanks for the advice! I will check those things out.
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