Idle Guru's needed! 2008 Charger SRT8 Cammed and Procharged

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05-13-2020
Musky@RG

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Idle Guru's needed! 2008 Charger SRT8 Cammed and Procharged

Hey guys, I have a 2008 Charger SRT8 which has a cam (not sure of the specs) and a Procharger. The car runs and drives beautifully however when it's cold the startup is giving me issues. It starts right away and the rpm spikes up to 1800 but then drops down quickly and stalls. It progressively gets better as it reaches operating temp. I'd like to see the throttle blade open more, hold, and then slowly close till it reaches target idle rpm. I've attached the tune file using the Beta software, I will get a log of it when it is cold tomorrow. Any help would be greatly appreciated.Attachment 99412
05-15-2020
dubbsix

Quote:

Originally Posted by Musky@RG

Hey guys, I have a 2008 Charger SRT8 which has a cam (not sure of the specs) and a Procharger. The car runs and drives beautifully however when it's cold the startup is giving me issues. It starts right away and the rpm spikes up to 1800 but then drops down quickly and stalls. It progressively gets better as it reaches operating temp. I'd like to see the throttle blade open more, hold, and then slowly close till it reaches target idle rpm. I've attached the tune file using the Beta software, I will get a log of it when it is cold tomorrow. Any help would be greatly appreciated.Attachment 99412

Will check ack for tune file.
05-15-2020
coanan

Quote:

Originally Posted by Musky@RG

Hey guys, I have a 2008 Charger SRT8 which has a cam (not sure of the specs) and a Procharger. The car runs and drives beautifully however when it's cold the startup is giving me issues. It starts right away and the rpm spikes up to 1800 but then drops down quickly and stalls. It progressively gets better as it reaches operating temp. I'd like to see the throttle blade open more, hold, and then slowly close till it reaches target idle rpm. I've attached the tune file using the Beta software, I will get a log of it when it is cold tomorrow. Any help would be greatly appreciated.Attachment 99412

Is it normal to have the startup inj pw scalar that high. 12,000.
05-15-2020
dubbsix

Quote:

Originally Posted by coanan

Is it normal to have the startup inj pw scalar that high. 12,000.

I am also seeing some weird values in other tables. Is there a chance this tune is corrupted and leading to the issues described? Startup Airflow is missing column entries...
05-20-2020
Musky@RG

Quote:

Originally Posted by dubbsix

I am also seeing some weird values in other tables. Is there a chance this tune is corrupted and leading to the issues described? Startup Airflow is missing column entries...

Thanks for the reply. Any chance you could share a screen shot of the Startup Airflow tables I'm missing? I loaded up a stock 2008 Charger SRT8 tune file from the tune repository and it seems to have the same tables as my file.
05-20-2020
coanan

Quote:

Originally Posted by Musky@RG

Thanks for the reply. Any chance you could share a screen shot of the Startup Airflow tables I'm missing? I loaded up a stock 2008 Charger SRT8 tune file from the tune repository and it seems to have the same tables as my file.

What about the MAP settings in airflow-general? I'm only a copy and paste guy by comparing tunes. You running a 2-BAR MAP?
I always see linear 46.38 offset 4.80. You have 45.11 7.00, not sure if it makes a diff. Most people say turn off Boro learn also, all speculation on my part. It's why good tuners get so much to tune, shits hard to understand, for me anyway.

Only tip I can give you is, if you can't afford a good tuner you have to find tunes with similar MODs and start comparing and changing till it runs right. It's how I did mine, not perfect, but I can start, putt around parking lots, idle for hours and it doesn't give me any trouble. Perfect, nope, but it was free. One day I'll find a tuner with a dyno and get it dialed in.

The other thing is to save each tune as a new revision 0001 thru 0999, if changes are really bad you can revert back to a previous tune and start over.
05-20-2020
Musky@RG

Quote:

Originally Posted by coanan

What about the MAP settings in airflow-general? I'm only a copy and paste guy by comparing tunes. You running a 2-BAR MAP?
I always see linear 46.38 offset 4.80. You have 45.11 7.00, not sure if it makes a diff. Most people say turn off Boro learn also, all speculation on my part. It's why good tuners get so much to tune, shits hard to understand, for me anyway.

Only tip I can give you is, if you can't afford a good tuner you have to find tunes with similar MODs and start comparing and changing till it runs right. It's how I did mine, not perfect, but I can start, putt around parking lots, idle for hours and it doesn't give me any trouble. Perfect, nope, but it was free. One day I'll find a tuner with a dyno and get it dialed in.

The other thing is to save each tune as a new revision 0001 thru 0999, if changes are really bad you can revert back to a previous tune and start over.

I actually am the tuner. LOL. I received the car which was tuned by another shop and was running horribly. It's running great now except cold start. Yes its running a 2 bar map sensor. it's reading accurate so I didn't want to touch the settings.
05-20-2020
coanan

Quote:

Originally Posted by Musky@RG

I actually am the tuner. LOL. I received the car which was tuned by another shop and was running horribly. It's running great now except cold start. Yes its running a 2 bar map sensor. it's reading accurate so I didn't want to touch the settings.

O - okay, sorry about that. Guess these cars are tough to tune.
05-20-2020
B00STJUNKY

Quote:

Originally Posted by Musky@RG

I actually am the tuner. LOL. I received the car which was tuned by another shop and was running horribly. It's running great now except cold start. Yes its running a 2 bar map sensor. it's reading accurate so I didn't want to touch the settings.

Assuming you're using a 2.25 bar MAP sensor from the Neon SRT-4 platform (which everyone simply refers to as a 2 bar sensor), and you're using the values mentioned in this thread (45.11 Linear, 7.00 Offset), while the resulting net difference isn't going to be massive, it may be contributing to some of your issues.

Using those values will net a very similar result at ~ 100 kPa, which would generate a voltage of ~2.15
Correct values will result in a kPa value of 99.88 @ 2.15 volts
Your values will result in a kPa value of 99.48 @ 2.15 volts

The offset won't really show itself until you're further away from where things just coincidentally line up fairly close, for example, the closer you get to either the minimum or maximum range of the map sensor's measuring capabilities, your net result will be more and more offset from true conditions.

Example:
At 0.5 volts, the correct values will net 23.35 kPa.
At 0.5 volts, your values will net 25.04 kPa.

At 4.85 volts, the correct values will net 225.11 kPa.
At 4.85 volts, your values will net 221.27 kPa.

Again, not massively different, but enough to throw fueling and spark calculations off a bit. I'd recommend fixing that first (assuming you're using the MAP sensor we think you're using), then you'll need to tackle the airflow model to get things stabilized.