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how do i tune this out?

tektic

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Dec 19, 2012
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ronkonkoma, ny

Timing is already kind of low do i need a richer mixture? This is about 22-24psi
 

GSTwithPSI

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Jan 1, 2012
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I wouldn't richen it. I'd shoot closer to 11.0:1, actually.

All you can really do is pull some timing, but 10 degrees is already pretty low. Why are all you guys getting knock on such low timing? Even when I was on 93, I was around 14-16* peak. Is the gas where you guys are really that shitty?
 

tektic

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Dec 19, 2012
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ronkonkoma, ny
I don't know higher compression higher piston speed?
So richer by half a point.
 

OldHairyBastard

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What's your base fuel pressure set to? Make sure the regulator vacuum line is hooked up and not leaking so that it will rise with the boost pressure.
 

tektic

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Dec 19, 2012
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ronkonkoma, ny
My logged afr is following my target pretty well. What would testing fuel pressure yield? I'm using a stock turbo regulator.
 

GSTwithPSI

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Quoting tektic:
I don't know higher compression higher piston speed?
So richer by half a point.



What's your compression ratio? You only spun it up to ~5,500 RPM in the last gear you were in when you saw knock. You spun it up way past that in the first gear you were in with no knock, so I don't see how piston speed would be an issue.

Those TunerPro logs are hard as f*** to read after being spoiled with ECMlink. I don't see your target AFR graphed, unless I'm just missing it? Can't you overlay all that sh*t on one graph, or no?
 

OldHairyBastard

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I want to make sure that your fuel pressure is set at a good baseline of around 36-45 PSI depending on the injectors but if your using the stock regulator you have no clue what the fuel pressure is and what its holding at while running WOT. You might see a drop in fuel pressure in the RPM range where you see the knock occurring which could be from poor atommization from low pressure which you can't tell from your air/fuel readings. That goes with the other question to make sure that the vacuum hose was attached because for each pound of boost the regulator will increase the baseline fuel pressure by equal amount so if you have a baseline fuel pressure of 45PSI then at 20 pounds of boost you will have a fuel pressure of 65PSI to accommodate for the extra pressure. I'd recommend an after market FPR anyway to be able to control your fuel pressure better and to be able to add a pressure gauge so you know for sure where you stand. Your stock regulator could be bad so I was trying to rule out that possibility as this is a process in trouble shooting or debugging.

Quoting tektic:
My logged afr is following my target pretty well. What would testing fuel pressure yield? I'm using a stock turbo regulator.

 

thecman02

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Nov 3, 2007
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Location
Kalamazoo,MI
What turbo are you running? I see your running 9:1 CR based off your modifications list in your profile. I would definitely run it richer at about 11:1 as said farther up. You'll get more power from boost and timing than leaning the mixture. When I was running pump with a 59mm turbo I couldn't get much more timing than that at the same compression ratio and rpm.
 

tektic

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Dec 19, 2012
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ronkonkoma, ny
The piston speed increase I was referring to is due to the 94mm crank. The target afr is not graphed but I tuned the maf comp pretty carefully. The logged air fuel is pretty spot on. This car is running a small 16g with ported evo3 turbine and o2 housing. I thought 11.5:1 was ideal. I will try 11 afr above 5k in my last row. I'm still using stock sized load levels.
 

strokin4dr

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Aug 30, 2005
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Location
Savannah, GA
11.5 afr with 9:1 compression & 93 oct is too lean for me. I aim for about 11.1 also on 93.
 
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