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Thread: 2018 Camaro 6.200 loud noise on start up

  1. #1
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    2018 Camaro 6.200 loud noise on start up

    hello Guys
    all Camaro (this one is AT8 with NPP) when start up at cold goes up a bit on RPM and makes a good loud engine noise.
    if you add a Borla Exhaust it becomes a real loud exhaust and neighbours are not happy

    so, what's the way to lower the noise on start up and make it quiete?
    if I think on genV Escalade you barely notice when you start the engine

    thank you!
    best regards

  2. #2
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    Quote Originally Posted by Christian GM View Post
    hello Guys
    all Camaro (this one is AT8 with NPP) when start up at cold goes up a bit on RPM and makes a good loud engine noise.
    if you add a Borla Exhaust it becomes a real loud exhaust and neighbours are not happy

    so, what's the way to lower the noise on start up and make it quiete?
    if I think on genV Escalade you barely notice when you start the engine

    thank you!
    best regards
    Try going to Engine > Exhaust > Min/Max ECT
    Set Min ECT to 300
    Set Max ECT to -100

    That should help a lot. By default, it retards the timing a bunch so that it's still combusting when the exhaust valves start to open which helps heat up the cats faster for emissions purpose. So on a cold start you're hearing more of the combustion process because of this, making it louder than normal.

    cat warmup.png



    EDIT:
    To add, if you have dual mode exhaust, you can go to System > General > Exhaust Rumble Enable and change them all to 0 (or just the ones for the mode that you're in when you start your car at home). I lost my NPP exhaust when I went with a full exhaust that didn't have NPP feature so, I forget this part exactly. I'm pretty sure this is what forces it to start with the NPP valves closed.

    rumble.png
    Last edited by g26er; 04-07-2020 at 08:34 AM.
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  3. #3
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    The exhaust will be loud for the 1st 60-90 seconds. It is caused by the dual pulse timing that is used to help the cats fire off faster.

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    Quote Originally Posted by Sneakyws6 View Post
    The exhaust will be loud for the 1st 60-90 seconds. It is caused by the dual pulse timing that is used to help the cats fire off faster.
    thank you both!
    the car has long tube headers with high flow cat.
    so emission is not an issue at all
    I will play with some number on Thursday morning opefully!

    bye

  5. #5
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    Quote Originally Posted by Sneakyws6 View Post
    The exhaust will be loud for the 1st 60-90 seconds. It is caused by the dual pulse timing that is used to help the cats fire off faster.
    Split pulse is disabled on my '18 SS A8 from the factory. I would think it would be on his as well. I'm pretty sure it's super low timing on start to get the cats to light off by igniting later so the exhaust valve will start opening while the combustion event is still happening making the exhaust hotter helping to light off the cats (best I can explain it ) and doing this will stop it.
    Engine > Exhaust > Min/Max ECT
    Set Min ECT to 300
    Set Max ECT to -100

    Quote Originally Posted by Christian GM View Post
    thank you both!
    the car has long tube headers with high flow cat.
    so emission is not an issue at all
    I will play with some number on Thursday morning opefully!

    bye
    Let us know how it turns out!
    2019 Corvette Grand Sport Black

    2018 Camaro SS Bright Yellow

  6. #6
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    Quote Originally Posted by g26er View Post
    Split pulse is disabled on my '18 SS A8 from the factory. I would think it would be on his as well. I'm pretty sure it's super low timing on start to get the cats to light off by igniting later so the exhaust valve will start opening while the combustion event is still happening making the exhaust hotter helping to light off the cats (best I can explain it ) and doing this will stop it.
    Engine > Exhaust > Min/Max ECT
    Set Min ECT to 300
    Set Max ECT to -100


    Let us know how it turns out!
    I am surprised the split pulse it turned off, the table is filled out and it is active on my 17 Camaro SS from the factory.

  7. #7
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    As g26er has stated, the loud fire up and flair can be tuned out. The flair up will require changing other tables to have it start gently. But the 30-60 seconds of loud exhaust is exactly because of the timing being pulled back to near 0 to warm up the cats and the idle speed being set around 1000 RPM as well for the first few seconds.

    IIRC split pulse is only used during cranking and not after the car is started and would have no influence on how the car sounds after you the starter disengages.
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  8. #8
    Senior Tuner Higgs Boson's Avatar
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    split pulse is only enabled for cranking on any genv tunes I have seen so far.

  9. #9
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    it works!
    thank you all

  10. #10
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    Quote Originally Posted by Christian GM View Post
    it works!
    thank you all
    Glad you got it!

    Stay safe everyone.
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    Quote Originally Posted by Higgs Boson View Post
    split pulse is only enabled for cranking on any genv tunes I have seen so far.

    I can tell you for sure, the split pulse tables do affect start up and the 1st 60-90 seconds of run time. I had to fix the tables and put them back to stock when my tuner modified them. He had them zero'd out and the car did not start normally (it was quiet, didnt ramp up and would hunt for idle until it went to closed loop). As soon as I returned the split pulse table back to stock the car fired back up like stock with the aggressive ramp up, the high 1k RPM idle and the louder exhaust.

    That table does more than just start the car, it stays active while the vehicle is in open loop and warming up the cats and then tappers off once the vehicle transitions over into closed loop.

  12. #12
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by Sneakyws6 View Post
    I can tell you for sure, the split pulse tables do affect start up and the 1st 60-90 seconds of run time. I had to fix the tables and put them back to stock when my tuner modified them. He had them zero'd out and the car did not start normally (it was quiet, didnt ramp up and would hunt for idle until it went to closed loop). As soon as I returned the split pulse table back to stock the car fired back up like stock with the aggressive ramp up, the high 1k RPM idle and the louder exhaust.

    That table does more than just start the car, it stays active while the vehicle is in open loop and warming up the cats and then tappers off once the vehicle transitions over into closed loop.
    Yes, most cranking and startup functions decay over time. We don't see very many tables in the E92.

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    Latest VCM Suite version does not have exhaust menu

    VCM Suite V5.0.4 does not have exhaust menu in Engine menu. How can I make quieter cold start up my Chevy Camaro 2017 6.2L V8. It's too much louder. My neiborhood are complaining a lot

  14. #14
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    Quote Originally Posted by kbkgo View Post
    VCM Suite V5.0.4 does not have exhaust menu in Engine menu. How can I make quieter cold start up my Chevy Camaro 2017 6.2L V8. It's too much louder. My neiborhood are complaining a lot
    You need to use version 4.10
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    Thanks TriPinTaz. I got the old version and there are exhaust tab to modifications.