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Noob tuning log

muleunit

Proven Member
70
0
Apr 2, 2009
Pittsburgh, Pennsylvania
How does this log look? Im very new to tuning and would appreciate if somebody could please help me or give me advice. This was a 3rd gear pull from 1800rpm to 6000 rpm

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gofer

Moderator
8,078
1,198
Feb 18, 2006
South Gilbert, Arizona
Everything in that WOT log looks good until about 5k RPM when you run out of injector and you start going lean. Your at 100% IDC at 5k and when you start leaning out on the wideband the engine starts to knock (detonate) which is exactly opposite of what you want. You need to upgrade to a bigger injector or you can turn up the base fuel pressure at your regulator and squeeze more out of those 450cc injectors. You also need to go through and smooth out your SD configuration map, the cells you've edited need to be similar in value to the cells next to them. You do this because the ECU will interpolate between two cells depending on where in the map its getting its values.

Heres a screen shot of what my SD config map looked like after the car was tuned so you get an idea of what I'm talking about Remember each car is completely different so copying and pasting mine will get you nowhere...
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:dsm:
 
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muleunit

Proven Member
70
0
Apr 2, 2009
Pittsburgh, Pennsylvania
quick question, I know the x axis on the VE table is RPM, what is the Y axis? Also what does the number in each cell mean? Higher number=more fuel? Thanks so much.
 

gofer

Moderator
8,078
1,198
Feb 18, 2006
South Gilbert, Arizona
The y-axis is absolute manifold pressure which is just a fancy term for how much boost your running plus ambient pressure which is 14.7 at sea level. When your tuning your VE table your also going to want to open up your DA OpenLoopMaxOct table as well and track it in the log.

If your DA OpenLoopMaxOct targeted AFR was a 11.1:1 AFR but your wideband reading being logged was a 12.1:1 AFR then you need to make adjustments to your VE table. Here's the equation you'll use to get your AFR's where they need to be...
New VE = VE cell being used (actual AFR / target AFR)​
Lets say that you did a WOT 3rd gear pull and you noticed your WB started to go lean. Open the log up and track it in your VE table and the value of the VE cell being used is 83. Next you open your DA OpenLoopMaxOct table and track it, a cell in the table will illuminate the target AFR which was a 11.1:1AFR. Then look at your datalog of the WOT pull and see what your WB was reading, this is your actuall AFR and we'll say it was a 12.1:1. So now we have the numbers we need to plug into that equation and make changes to our VE table...
83 (12.1 / 11.1) = 90.5​
So at that VE table cell you'd INCREASE the VE to richen the AFR, you'd also increase the surrounding VE cells as well.

:dsm:
 
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muleunit

Proven Member
70
0
Apr 2, 2009
Pittsburgh, Pennsylvania
Okay so the VE table isn't used in vacuum? Then how do I richen or lean out my idle/cruise? Sorry for asking so many questions but Im having a hard time understanding this.
 

gofer

Moderator
8,078
1,198
Feb 18, 2006
South Gilbert, Arizona
Okay so the VE table isn't used in vacuum? Then how do I richen or lean out my idle/cruise? Sorry for asking so many questions but Im having a hard time understanding this.
Absolute pressure isn't EXACTLY the boost pressure you see on your gauge, let me explain it a bit.
Absolute pressure = gauge pressure + ambient pressure​
-Ambient pressure is sometimes referred to as 1 bar and is equal to 14.7psi at sea level.
-Gauge pressure is relative to how much boost your running.

So your car DOES use the VE table in vacuum, and sorry for the bit of mis-information about the absolute pressure reading on the y-axis.

While the cars idling start a log and open up your VE table, select track datalog and notice which cells illuminate. Those are the cells the ECU's pulling the info from to get your idle/cruise fuel trims. The easiest way to get your CombinedFT hovering around 0% is using the SDVEAdjust (CombinedFT) tool after you go for a 10min. drive. You just right click the log and select SDVEAdjust (CombinedFT) and it will give you suggested VE updates to the table. That tool will only give inputs on cells that you hit during the cruise though, thats why you need to smooth things out a bit so your not jumping drastically from cell to cell.

My car idles at 850 rpm and a absolute pressure of 5.5, that means the ECU will interpolate between the 500 and 1000 RPM cells at 5.5 absolute pressure block. It all depends on YOUR CARS setup what VE cells it uses though thats why you need to look at the VE table while its tracking a datalog at idle.

:dsm:
 
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