09-14-2022, 09:28 AM | #1 |
Drives: 2021 2SS Join Date: Sep 2022
Location: Long Island, NY
Posts: 31
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Dual Mode Exhaust Question
It is well established that AFM can be disabled thru a simple toggle switch when tuning, does anyone know if dual mode exhaust can be tuned, as in being able to change the valve actuation points? For example, I want stealth to be closed all the time, track to be open all the time, and sport and tour will open up somewhere in between (3-6k). Hoping to bring the car to a local tuner and have both of these features tuned out, if this is not possible I will purchase the Range AFM disabler and Mild2Wild controller. If anyone knows if this is possible please chime in!
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09-14-2022, 11:45 AM | #2 |
Drives: 2018 Camaro 2SS A8 Join Date: Jul 2017
Location: East Tennessee
Posts: 11,627
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I have not done this myself and actually don't mind stock-ish settings, but here is where you need to experiment. The "Exh Value RPM thresholds" table defines RPM bands 1 to 4 that will in turn be used by the separate open and close percentage tables in each mode (these allow for hysteresis).
Not 100% sure, but I think mode 0 is tour/snow, mode 1 is sport and mode 2 is track. A value of -1 in these tables means the valves are fully open and 100 means fully closed. It's not as simple as an on/off switch, but I quite like the nuanced approach, wish some of this configurability was lifted up into infotainment config screens.
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09-14-2022, 01:49 PM | #3 |
Drives: Wild Cherry LT1 Join Date: Dec 2016
Location: Massachusetts
Posts: 1,926
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You may want to confirm you’re not creating a problem for yourself closing NPP full time in stealth mode…in particular, at full throttle… It may not be an issue, but I’d be concerned about back pressure, loss of power and possible codes. Maybe I’m off base, but figured I’d mention it. I’m sure a tuner would know…
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09-15-2022, 12:47 PM | #4 |
Drives: 2017 1SS 6spd Join Date: Jan 2011
Location: Utah
Posts: 2,869
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I'm pretty sure the owner's manual warns against prolonged operation of the engine in stealth mode (went thru the manual quickly, but couldn't find the reference).
Anyone who has done a 5am start-up in stealth mode knows the valves open briefly (you cringe and try to think of all the nice things you've done for your neighbors). I figure this is necessary to 1) warm up the cats per EPA requirements and 2) help the car start quickly and not foul a plug. IMO, bypassing any valve opening could lead to issues caused by excessive back pressure as Chutzpah mentioned. I like the factory set up that I've fine tuned to keep the exhaust sound management in Track at all times, no matter the suspension setting (don't have to get up at 5am anymore!), but I really enjoy how the NPP will still close the valves at light throttle and then open them when you give her the GAS! With a Rev matched downshift, you can surprise folks from time to time. I guess I'm still just a kid at heart- or juvenile delinquent! |
09-15-2022, 04:26 PM | #5 |
Drives: E92 BMW M3 Join Date: Oct 2012
Location: Houston
Posts: 4,496
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Stealth mode issue is about prolonged use at high RPMs. Creates too much heat, people have melted their diffusers at the track.
Keeping them closed under normal driving conditions would be okay.
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09-16-2022, 08:20 AM | #6 |
Drives: 2019 Chevrolet Camaro Join Date: Mar 2020
Location: Lantana, TX
Posts: 77
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what I did was set track mode to always open. take track mode setting and move them to Sport. I set the valves to close in 6th gear in sport so freeway driving was quite. On touring mode I left it as it was programed except I added quite start so it will start with the valves closed.
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Tags |
dual mode exhaust, tune, tuning |
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