Need help with tuning 2016 Camaro 2SS Manual with LT4 Engine

[travislambert]

On to the next problem...

So to fix the last problem I moved my VVE table values over to a mostly CTS-V tune (spark timing, VE zone boundaries, etc). This made the car run the best it has to date, especially considering there was no speed density tune done on this setup.

I configured this tune for speed density tuning and discovered right away there are some zones that need some major adjustment under this setup. The problem is I can't seem to make HP tuners generate reasonable Coefficients for the zones. It always ends up computing some bogus values.

Tune:
161 2016 Camaro SS LT4 - Speed Density.hpt

Before:
161 VVE Before.jpg

Delta needing applied:
161 EQ Error.jpg

After:
161 VVE After.jpg

What's the best approach here. I've tried smoothing, etc., but the values will never seem to go where I need them to be. I know the zones can be redefined, but I'm unsure of the implications of this. Besides, I'm sure that will completely throw off the Prediction Coefficients and I have no idea how to get those adjusted properly from scratch.

Please advise. Thanks

[5FDP]

You do want your MAF dtc's to be on first error, that way it drops straight into Speed density. Having them on second error or no error reported isn't the correct way to do it.

[travislambert]

You do want your MAF dtc's to be on first error, that way it drops straight into Speed density. Having them on second error or no error reported isn't the correct way to do it.

Hmm... What will be the symptoms of the way I have it? I was just following a guide and it seemed like it was working.

http://michigansnowmobiler.com/hptun...ons%20rev2.pdf

I did have the SES Enabled while SD tuning except for this last tune I posted, but the error mode has always been set to No MIL Light with the MAF frequency Fail High set to zero.

I certainly want to get this right so you have my attention I just need to know why "MIL on First Error" is better before I deviate.

[travislambert]

Question... What would be a normal intake MAP reading for an LT4 at idle (say 600 RPM)? I suspect my pressure is a little low. When the engine is off the Intake MAP reads the same as the Barometric Pressure (calculated from pressure sensor integrated with MAF). At my location it's 14.1 psi. At WOT + full boost it reads about 24 psi which is probably a touch higher than actual but within reason.

I created a graph to plot the avg PSI by RPM. Using a gentle run for data, here's what I'm seeing:

RPM - PSI
500 - 5.5
600 - 4.7
700 - 4.5
800 - 4.0
1000 - 3.8
1200 - 5.3
1400 - 5.4
...

It trends upward from there.

The reason I ask...looking at the VVE table, pressure ratio values for the CTS-V start at 0.45 I have actual values of .28 or so. Now I understand that the values are virtual, but this combined with the fact that the VVE stock airflow values for the LT4 are much higher than the values I derived from wideband tuning makes me suspicious.

[5FDP]

Hmm... What will be the symptoms of the way I have it? I was just following a guide and it seemed like it was working.

(http://michigansnowmobiler.com/hptun...ons%20rev2.pdf)

I did have the SES Enabled while SD tuning except for this last tune I posted, but the error mode has always been set to No MIL Light with the MAF frequency Fail High set to zero.

I certainly want to get this right so you have my attention I just need to know why "MIL on First Error" is better before I deviate.

That guide is a good one but the DTC information is wrong though. P0103 must be set to first error with the DTC present for the computer to know that the MAF isn't going to be used. Not having it on first error with No error reported or No MIL light doesn't completely tell it to use VVE only.

[SultanHassanMasTuning]

Hmm... What will be the symptoms of the way I have it? I was just following a guide and it seemed like it was working.

(http://michigansnowmobiler.com/hptun...ons%20rev2.pdf)

I did have the SES Enabled while SD tuning except for this last tune I posted, but the error mode has always been set to No MIL Light with the MAF frequency Fail High set to zero.

I certainly want to get this right so you have my attention I just need to know why "MIL on First Error" is better before I deviate.

link not working, interested to see what is going on.

the tune is just all over the place.

[Higgs Boson]

Question... What would be a normal intake MAP reading for an LT4 at idle (say 600 RPM)? I suspect my pressure is a little low. When the engine is off the Intake MAP reads the same as the Barometric Pressure (calculated from pressure sensor integrated with MAF). At my location it's 14.1 psi. At WOT + full boost it reads about 24 psi which is probably a touch higher than actual but within reason.

I created a graph to plot the avg PSI by RPM. Using a gentle run for data, here's what I'm seeing:

RPM - PSI
500 - 5.5
600 - 4.7
700 - 4.5
800 - 4.0
1000 - 3.8
1200 - 5.3
1400 - 5.4
...

It trends upward from there.

The reason I ask...looking at the VVE table, pressure ratio values for the CTS-V start at 0.45 I have actual values of .28 or so. Now I understand that the values are virtual, but this combined with the fact that the VVE stock airflow values for the LT4 are much higher than the values I derived from wideband tuning makes me suspicious.

Over 14.1 or 14.7 is boost. Change you scanner units for psi to kpa.

Pressure Ratio is MAP kpa / Baro kpa

If you idle with 45 kpa at the MAP and have 14.1 Baro (97kpa) then you would be at .46 PR

[travislambert]

Over 14.1 or 14.7 is boost. Change you scanner units for psi to kpa.

Pressure Ratio is MAP kpa / Baro kpa

If you idle with 45 kpa at the MAP and have 14.1 Baro (97kpa) then you would be at .46 PR

Thanks for your reply. I understand how the ratio is calculated. I'm just trying to figure out if my intake MAP values are normal or if I should be looking for a problem.

[Higgs Boson]

Thanks for your reply. I understand how the ratio is calculated. I'm just trying to figure out if my intake MAP values are normal or if I should be looking for a problem.

switch to kpa so we don't have to convert all your posts. ;-)

24 - 14.1 = 9.9 psi which is basically stock boost.
5 psi = 34 kpa

my 2016 Z06 idles at 34 kpa

[Higgs Boson]

Here is an idle log so you can see where you need to be:

idle.hpl

[travislambert]

Here is an idle log so you can see where you need to be:

idle.hpl

Thank You! I appreciate the log.

It looks like my MAP readings are okay. So I guess I'm back to my original problem (post #41).

[Higgs Boson]

for that problem go to the speed density section and redo the zone boundaries to what makes sense for your application. you can't just paste numbers from one tune to another, the axis' are/can be different, the zones are different, etc etc.

[travislambert]

for that problem go to the speed density section and redo the zone boundaries to what makes sense for your application. you can't just paste numbers from one tune to another, the axis' are/can be different, the zones are different, etc etc.

Thanks Higgs. You were absolutely right. I was trying to avoid adjusting the zone boundaries, but it just wasn't working out.

I still haven't wrapped my head around why the CTS-V airflow isn't a little closer to what I have given that the airbox, engine, exhaust, etc. is identical. Maybe I'll figure out where the difference is one day.

Anyway, I only had to make one minor adjustment so far to the pressure zone boundary and things seem to be working out much better.

I'll get it eventually. I make progress every day. Between work, life, and weather there just aren't many hours left in the day to work on the car.

Thanks again!

[travislambert]

Here's my latest VVE:

174 VVE.png

Here's the tune:

174 2016 Camaro SS LT4 - Speed Density.hpt

I still have some more tuning to do, but most cells are withing a couple percent of lambda. I plan to refine the higher air ratio sections tonight or tomorrow.

I'm always seeking feedback, suggestions, LT4 example tunes/logs, etc..

[Higgs Boson]

I personally like to smooth it and retune it about 100 times until it's both correct AND smooth.

[travislambert]

I personally like to smooth it and retune it about 100 times until it's both correct AND smooth.

Can you elaborate on what types of changes would help to accomplish a smooth graph? Forgive my ignorance, but will simply smoothing and readjusting get me there?

[travislambert]

Also, can anyone offer advice on the table boundaries. The LT4 engine could easily reach pressure ratios of 1.7, so should I extend my table out to 1.7 on the pressure ratio? I noticed the factory tune ranges are very limited, so I'm guessing there's a tradeoff with precision or maybe they rely on fuel trims or MAF sensor?

[travislambert]

I could really use some help here. I've spent the last day attempting to get my graph to smooth, but it seems no amount of adjustment will get rid of the big spike at 1400 RPM/0.48 pressure ratio. Any adjustment to the boundaries in this area end up being too far from where the wideband tells me I need to be.

This is my first time trying to tune the VE, but the tools seem incredibly primitive. On the HP tuners VVE many standard keyboard shortcuts don't work (like ctrl+a). The undo button doesn't work after a coefficient generation. This is especially frustrating after it generates completely worthless coefficients for you.

I tried to get the bluecat tool to work, but the latest version I could find was 4.2.2 and that release doesn't appear to be intended for E92 coefficient generation.

If someone could offer some help with my last two questions (posts 56 and 57) I would appreciate it. Also, if there are any better VE table tools available please let me know. I've had about all the trial and error I can take.

[Higgs Boson]

you have to tune it. you can't adjust boundaries and expect it to be right. you have to tune each cell based on fueling error. set your axis and your boundaries then tune the table.

[travislambert]

you have to tune it. you can't adjust boundaries and expect it to be right. you have to tune each cell based on fueling error. set your axis and your boundaries then tune the table.

I'm sorry but I don't have any experience to pull from here, and I haven't found any good documents outlining the details for tuning these tables.

I've been correcting the table cells after boundary adjustment, recalculating coefficients, etc.. That worked out okay for some areas of the table as I was able to smooth the graph as well as lower the average error, but I can't seem smooth around the 0.48-0.5 pressure ratio line without a lot of fueling error in a few of the cells. Is there something I should be looking for here? Why would there be spikes? I have about 300 miles of wideband data and I would expect for it to have averaged out by now if it were actually error.

Should the boundaries cover all of the pressure ratios I could ever hit? The stock tunes seem to focus only on a subset in the middle, so I don't know if that's better for some reason.