XJGPN

Actually, that's a good point... anyone have a MAF table for that SLP lid that was available as an option on SS's? Regardless... Went out again, this time I tried the Closed loop SD tune. My car just plain will not even start without the MAF. Starts and idles really nicely with the MAF, but if I pull the maf, car seems to start okay, but then stumbles and dies. If I give it any gas it dies immediately. Are my VE tables just that far off, or is it something else I am missing? Regardless, since this is becoming my tuning log I figured might as well give specs:

Stock longblock
Stock Heads
TR224/112 Cam.
918 springs
Ti Retainers
Grot. headers
QTP/Mufflex Y-pipe.
Mufflex 4" with Borla XR-1 Muffler.
Stock throttle Body/Stock MAF.
LS1 Motorsports Lid.
T56.

I think those are all the applicable mods. As you can see, pretty basic setup.

Another_User

It doesn't matter. I thought of that a long time ago. You might as well just get a Blackwing lid. If you look, it has the same oval shaped opening that the stock lid has, which is why it can use the same MAF table. That's why they aren't the same lid. SLP had to engineer it around GMs programming because they already knew it would be a problem. It would have been nice if they told us.

Bink

Don't forget that cams with narrower LSAs alter the airflow measured by the MAF due to overlap/reversion. Also, some fuel and O2, via the open intake valve during overlap, is exhausted - throwing the AFR somewhat lean at idle. FWIW.

XJGPN

I am a MORON! I just realized what I was doing wrong. Haven't actually tried it, just uploaded the new program... Will test it out in about a half hour. I set the 3 DTC codes to 3-No Error Reported instead of 2-No Mil Light. I can't believe I did that. I think I was just so used to going to 3 rather than outright turning off the code, I wasn't thinking. So, For anyone reading this, in the directions where it says: "2: Disable the SES lights for MAF codes P0101, P0102, P0103 (No check engine light.) Do not completely disable the codes or the PCM will not fall into SD mode. Only turn off the SES light, DO NOT DISABLE THE CODES THEMSELVES!" The setting is 2. I knew that, I read the warnings a million times and still somehow missed it... TWICE! I'm so angry with myself... I lost like 3 days of tuning because of that boneheaded mistake.

tici

iTrader: (1)

I tried to put the MAF in different angles, hoping to find out the best one with my Vortech setup.
It's all the same. No matter wich angle, the MAF table has to be adjusted.
What I see is that as soon you touch the intake the cells corresponding to low RPM and low MAP are more negative that usual (richer).
That's why I reduced the lower frequencies by 7%. The higher the frequency the lower the correction. After 4625 Hz I left the stock values.

CamTom12

iTrader: (1)

How did it work out?

Getting HP Tuners as soon as the check clears...

tici

iTrader: (1)

Look at those LTFT pictures...
Before and after changing the MAF table

XJGPN

Great! As you saw, kinda got a late start because of my own stupid mistake... but once I got that resolved, everything worked great. I did 4 iterations last night of moding the VE table then driving around for a half hour getting a log trying to populate all the cells. Things are pretty consistant now across the board. Since everything was pretty close, for the last change to the VE table I didn't use the "quick and dirty" method of using an Excel spreadsheet setup with the formula (AF/13.0) as a multiplier for all the cells in the VE table. I went cell by cell using the AF as a guide (and a Z06 table handy as a reference. Didn't use any of the Z06 numbers... just kinda used it as a reality check). I'll probably do a few more iterations of changing values cell by cell now. The VE table is close now, but it is not polished. I still have a bit of smoothing to do. Now comes the fun balance of keeping the table smooth, vs. the AF ratio in that cell.

PS- You won't regret getting the software. It really is as great as everyone says.

JimMueller

iTrader: (9)

So when one finishes with the SD tuning phase and if one decides to re-enable the MAF, how do we determine which RPM's to scale and by how much?

XJGPN

There is a really good excel spreadsheet to help you do that on: http://ls1edit.slowcar.net/

Here is my update. I didn't disable DFCO, so occasionally I would get a false lean reading (as in ~~19.99:1). These anomalies were driving me nuts, and I thought it was something with the connection between the LM-1 and the computer. Once I realized that these symptoms could be caused by DFCO I disabled it. I did it by turning DFCO Enable Normal and DFCO Enable Clutch Transition to 250. Did an extremely long log and didn't get the anomalies any more. Hopefully this step will get added to the SD tuning directions soon. Regardless, the values didn't throw off my numbers too much... So hopefully won't add too much more time on getting this VE table tuned in. My biggest thing now is just smoothing it... I read the suggestions for hand smoothing the graph... but I can still see it being a tough battle between making it look pretty and getting the data in a given cell to hit my target. If I figure out a good method, I'll pass it on. Right now I'm thinking I'm just going to take the VE table I have, keep hitting the polynomial smoothing to get an idea of where the numbers would fall totally smoothed out, then compare those values to my current values and the resultant AF ratio and see if I can find a middle ground.

CamTom12

iTrader: (1)

I saw a video once of an Aussie car starting and the guy (I guess 'Bloke' is appropriate here, hahaha ) saying something like "sounds nice for a cam they say couldn't idle. That's what you call Speed Density tuning," or something like that

Why don't more people here tune in SD? Are there any major drawbacks other than emissions testing?

Sorry if I'm off topic...

XJGPN

Honestly, I don't know how someone would have done it prior to HP tuners. That was one of the big advantages to the stand-alones... they can data log for each cell... with a wideband... Which HP tuners now does. It would be so time consuming if I had to export the data to excel and number crunch every time I wanted to check data... not to mention the fact that the enhanced interface lets me get accurate wideband data, whereas previously it would have been off of LTFTs and STFT's.. As for what they said about idling... MAFs tend not to idle well with big cams because the reversion basically throws off the MAF signal.

NicD

iTrader: (7)

Very easily. Use a wideband and write down the values you need to change in your VE table, repeat. HP tuners just makes it quicker.

XJGPN

How would you have logged a histogram to know exactly which cell in the VE table to modify without being able to log your MAP sensor, RPM and AF with the same device? I'm not saying it couldn't be done, just that it would be so much more time consuming than it is using the histogram and enhanced interface with HP tuners.

NicD

iTrader: (7)

That is what efilive, autotap, or another scanner is for with a wideband device. Like I said, hp tuners made it quicker with their histogram.

TurboBerserker

iTrader: (1)

You scale the entire table. This step isn't about tuning individual cells, that's what the SD part of the process is for. This step is about scaling the MAF so that you are operating in the VE range.

So here's what happens -- you set your SD VE values, and plug back in the MAF. From then on your LTFTs and STFTs are going to be lean (mine went from 0 to -3 throughout the histo to 10 to 13) so you scale the MAF upwards to move the entire table back down.

One more thing -- after I scaled my MAF globally, to get the majority of the table back to 0 to -3, I have some sections (lower rpm and lower airflow) at -5. I haven't gotten back to the tune since then, but am not too worried about it.

I am also looking into the 4k+ rpm range which is 0 to 1 for me in lower airflow cells (this is the MAF only range). Not quite sure what to think about that yet. I am maxing the MAF at boost without question, but these ranges aren't under boost...