Tuning Diary: Scaling KSTech "Stock MAF" Intake

[grim]

Starting a tuning thread/diary to walk through scaling the KSTech Stock MAF LGT Intake I picked up from the GB.

 

Prior to scaling the MAF, I wanted to see how far off the intake was from the stock airbox in terms of corrections.

 

Three learning views are attached.

 

3/6 - ~5 miles post install

3/7 - ~50 miles post install

3/9 - ~100 miles post install

 

The group shows the learning progression over time.

 

Based on Learning C, and what I am seeing in the RomRaider scaling tab, learning D and open loop is probably running a touch lean. I don't want to run any WOT lots prior to at least a rough in of the scaling.

 

Stockmaf-1.jpg is a screenshot of my current Romraider MAF scaling tab with approximately 75 miles of data logging, over 5 sessions. I'm going to add 2 more sessions, about another 30 miles on, as well as some idle logging before I make my first pass on the correction.

 

Judging from what I'm seeing in closed loop, I'll likely correct the open loop portion by about 2% for the first pass. For the CL portion, I'll take approximately 50% of what the maf scaling tab suggests as the correction from 1.5v up. I'll smooth the new curve accordingly just to make sure there aren't any oddities. Once I'm satisfied with what I'm seeing, I'll move over to the closed loop portion and run some WOT logs to adjust.

 

It is worth noting that I'm not starting with a stock MAF scaling, it is altered from stock very slightly. Yes, I did rescale my stock airbox. Infamous scaled a portion of the MAF during Stage 2 tuning. The stockvsscaled image shows the adjustments I was starting out with. X is MAF(v), Y is g/sec. However, my total corrections would have been further off in the adjusted areas had I started with a stock scaling. Initial adjustments were done with Infamous during a Stage 2 tune, and I went forward from there.

 

Based on what I'm seeing, even though this is a "stock maf" sized intake, scaling is going to be required, as is largely expected.

 

I'll be posting my MAF scalings, scatterplots, logs, and LVs for reference as I move forward. My target will be +-1% across all ranges, all conditions, which I was able to achieve on the stock intake..

[NSFW]

Do you have a copy of Excel? I found it useful to scale my MAF as follows:

 

* Paste a MAF scaling table twice with a few blank rows in between.

* Fill one of those blank rows with 1s (call it the adjustment row).

* Replace all of the MAF values in the lower table with (top_maf_value * adjustment_cell).

* Pick a couple points in the MAF curve to tweak and replace the adjustment value (1) with whatever percentage changes are needed. In your case: 1.0 at 1.4v, 1.05 at 2.35v, 1.025 at 2.8v.

* Use Excel's "fill series" to make the adjustments ramp smoothly between cells at different voltages.

* The bottom MAF scaling table can then be copy-pasted into RomRaider.

 

The line that RomRaider drew over your scatter plot is so close to being linear that you might be able to get very close to 0% fuel trims in one iteration.

[grim]

I do have Excel and have used similar methods, but I didn't know that I could use Fill Series to generate the "tween" values in I set the key values at specific points.

 

I did get a few more miles in, so I've added in the screenshots of the RomRaider MAF scaling tab (yes, very linear between 1.3v and 2.3v) as well as an LV.

 

Making my first adjustments now, and heading out to flash.

 

Corrections are:

 

.99 at .90v tapering to 1.0 at 1.29v

1.0 at 1.29v to 1.41v

1.0 at 1.41v tapering to 1.02 at 1.72v

1.02 at 1.72v to 5v

[grim]

Ok, had to run some errands so I flashed and got about 45 minutes of logging in.

 

Logging wasn't as clean as I'd like, so I'll capture another day or so of driving (need more long distance highway logging) before I make the next set of tweaks.

 

At this point, looks like I need a minor correction at 1.5v as well as at the 2.3 to 2.4v range. I knew I would need to go back and fix the latter, since I only corrected that area by 2% (This was the area NSFW suggested a 1.05 correction, which was right on).

[yamie700]

Just curious what wideband are you using to scale the open loop?

[grim]

I've got an LC-1, but I've only ever run it off my tailpipe, and really just to play with it.

 

I need to take my DP off to weld in a bung, and the weather and my schedule just haven't cooperated.

 

I suppose I might just rig it up to make some rough-in passes.

[grim]

Ok, some more logging in, MAF tab and LV attached.

 

Only some minor corrections this time to fix the bump around 1.5v.

 

Corrections are as follows:

 

1.33 1.37 1.41 1.48 1.56 1.64 1.72 1.8 1.88 1.95

0.00 -0.01 -0.03 -0.07 -0.07 -0.04 0.00 0.03 0.02 0.00