HP Tuners MAF & VE tuning

Ross

Goblin Guru
I am near the end of may MAF (Mass Air Flow) tuning, and took the time to compare the stock 2006 Cobalt SS Supercharged MAF tune to the Goblin MAF tune.
The only difference is the shorter DF Goblin intake, with the DF supplied Edelbrock air filter, and the shorter 2.5" DF exhaust with the catalytic converter deleted.
But boy, do those changes make a difference! Or is the difference related to something else? Maybe a 13 year old MAF sensor? Do they wear?
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The chart shows "MAF Frequency" in bold along the top. (spreadsheet line 3) The MAF freq. basically follows the engine RPM, with higher freq. at higher revs.
Then for yesterdays tune, the pounds per hour of measured airflow for a given MAF Freq. (line 5)
Then for the stock tune, the pounds per hour of measured airflow for a given MAF Freq. (line 8)
The stock tune is 22% lean at idle... then gets pretty close in the mid RPM range, then gets real lean again when the supercharger is screaming.

Now a stock engine will learn the LTFT (Long Term Fuel Trims) up to 20% richer, as needed... but the first while when I started driving my goblin, I was running lean.
And even after the LTFT table get filled out, the engine will still be lean in places, until the STFT (Short Term Fuel Trims) adjust... which is forgotten every time you start your car.

After I finish the MAF tuning, I am moving on to the VE (Volumetric Efficiency) tuning.
I'm really hoping this makes the throttle easier to drive a supercharged goblin.
 
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Indy Lonnie

Well-Known Member
I just had mine dyno tuned at ZZperformance. Before tuning, I had codes showing lean idle. The first dyno pull showed AIr/Fuel ratios in the low 20s at idle... at the top end it was way lean and the power fell off like crazy. It wouldn't pull past 6000 rpm. You could hear it fall flat.
 

Ross

Goblin Guru
I just had mine dyno tuned at ZZperformance. Before tuning, I had codes showing lean idle. The first dyno pull showed AIr/Fuel ratios in the low 20s at idle... at the top end it was way lean and the power fell off like crazy. It wouldn't pull past 6000 rpm. You could hear it fall flat.
So a 2009 SS Turbo LNF is similiar to my 2006 LSJ SC I think it is the shorter intake and exhaust. Do you have the before/after tune for your engine? I would love to compare other peoples tunes. Did ZZP lock down your ECM after your tune? Some tuners do this (Trifecta), and that can be a real pain, as you can't tune it yourself or at another place.
 

JSATX

Goblin Guru
So a 2009 SS Turbo LNF is similiar to my 2006 LSJ SC I think it is the shorter intake and exhaust. Do you have the before/after tune for your engine? I would love to compare other peoples tunes. Did ZZP lock down your ECM after your tune? Some tuners do this (Trifecta), and that can be a real pain, as you can't tune it yourself or at another place.

Unfortunately the 2009 SS is completely different from the earlier models.

On an unrelated note I can send you mine if you have any interest in looking over it.
 

Ross

Goblin Guru
Unfortunately the 2009 SS is completely different from the earlier models.

On an unrelated note I can send you mine if you have any interest in looking over it.
Sure! I would like that. You can actually post it here in the forum if you want.
Yes, the 09 SS is completely different... but it seems to have the same issues if you shorten the intake and exhaust, and leave the stock tune, so in that context, they are similiar.
 

Indy Lonnie

Well-Known Member
ZZPerf kept my files. I do not have HP Tuners so it was meaningless at the moment. They have the final tune saved off if I should ever need it. They said I could purchase HP tuners and tweak I should like in the future. I don't think they locked it down...
I know the DF intake and exhaust definitely changed the tune from stock.

It is also so much quieter, smoother and well behaved now. My wife even noticed how much quieter it is now during normal driving.
 

Ross

Goblin Guru
Yesterday, I did 1 more day of MAF tuning, and then today I took it out of MAF tuning mode, and ran it with the corrected MAF data.
Wow! I it is a way easier to drive in 1st gear. No more jerky jerky! I am only half way thru a basic tune, but my goal of making it easier to drive is already accomplished, and it should only get better from here.
 

JSATX

Goblin Guru
Yeah, and then in the next tune I was sent it was dropped to 1200 RPM and ran worse.

It's my understanding that parameter controls when it switches from SD to MAF. So you are not using MAF tune until over 5800 RPM?

And I just checked the OEM value for my car, 7000RPM??
 
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Ross

Goblin Guru
Yeah, and then in the next tune I was sent it was dropped to 1200 RPM and ran worse.

It's my understanding that parameter controls when it switches from SD to MAF. So you are not using MAF tune until over 5800 RPM?

And I just checked the OEM value for my car, 7000RPM??
I thought MAF tune turns off at high RPM... you are on MAF during most of your mid RPM driving.
Maybe your tuner turned off MAF at a lower RPM because you are flowing more air earlier, and the MAF is hitting its' limit earlier than a stock engine.
Your speed density tune becomes much more important then.
 

Ross

Goblin Guru
The weather cooperated today, I was able to get in 11 runs doing VE (volumemetric efficiency, also called speed density) tuning.
Most of these tuning runs were 3-5 miles each, so it was a quick tune.
After calibrating the MAP sensor, I compared it to the stock Cobalt tune, and it was mostly within +/- 5% and occasionally 10% different.
 

JSATX

Goblin Guru
The latest goat rope video is about dynamic airflow if you haven’t seen it yet it’s basically what we were talking about above.
 

JSATX

Goblin Guru
My neighbor with the LSF Exocet is doing the $75/mo plan with him, said it was worth every penny. When I get back on the road I’m going to do it too.
 

Ross

Goblin Guru
My settings for VCM Editor in order to start VE Tuning.
In VCM Editor, if you open the file "20191104 VE tuning.hpt"
then go to Compare, and open this compare file: "Goblin LSJ MAF tune 205F fan -4MIL.hpt"

To see the changes, go to Compare, View comparison log.
The first change, Primary VE vs RPM vs MAP: Richen up the mixture (say 10%, all cells), so that the engine doesn't run lean while logging VE errors in open loop.
2nd change, Closed Loop Enable... : set the temp so high that the engine will never enable closed loop.
one change at a time you can see my settings.
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The last difference doesn't count, as I played with my fan temperatures, which is not related to VE tuning.
 

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ctuinstra

Goblin Guru
Looking at your VE tuning setup; I noticed that you are zeroing out the open loop adders. I was going to do this next but the Goat Rope never said anything about it in how to set up VE tuning. I have COT permanently disable since we don't have one anymore. Also you have Piston Protection turned off during tuning, I may try that also to see if that is causing issues. This helps me a lot. I will try some of these additional settings to see if I can get a better scan data.

You VE table is much more smooth than mine other than the huge spike at 46 kPa in the middle of the RPM range. 4096??!!


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Ross

Goblin Guru
That looks like bad data in my VE Table. I think I grabbed the wrong file for starting the compare.
I will edit my previous post, and include a better starting tune file.
[/QUOTE]
 

ccannx

Goblin Guru
Thanks for sharing I have been trying to pay more attention to HPtuners and finally got my wideband to work. Here is the dyno tune file from my recent dyno session. I asked the tuner if it was ok to share and he said he didn't mind. for some reason he couldn't get the MAF to work so its all VE tuned I believe.

He said there was some false knock issues so im not sure if timing was pulled because of it. I later found the guide bolts stripped off the timing chain and cleaned it all up and redid the timing.

"this is an 07 with 2.9 pully and 60lb injectors tune"

My settings for VCM Editor in order to start VE Tuning.
In VCM Editor, if you open the file "20191104 VE tuning.hpt"
then go to Compare, and open this compare file: "Goblin LSJ MAF tune 205F fan -4MIL.hpt"

To see the changes, go to Compare, View comparison log.
The first change, Primary VE vs RPM vs MAP: Richen up the mixture (say 10%, all cells), so that the engine doesn't run lean while logging VE errors in open loop.
2nd change, Closed Loop Enable... : set the temp so high that the engine will never enable closed loop.
one change at a time you can see my settings.
View attachment 14078
The last difference doesn't count, as I played with my fan temperatures, which is not related to VE tuning.
 

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