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Old 06-04-2020, 02:26 PM   #7
SSDan


 
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Drives: 2016 1SS 6MT NPP
Join Date: Feb 2010
Location: Lake Murray, SC
Posts: 2,261
Quote:
Originally Posted by enzia35 View Post
The super loud start up is for emissions. More fuel to heat up the cats faster.
This. I agree with others that other than forcing it into stealth mode prior to start there is little way to quiet the car down at start. The high rpm bark and high idle will still happen regardless of NPP exhaust mode or even exhaust type (along with a double pulse on the injector cycle for the first several seconds). All of this is there to make the car run super rich at a cold start up so the cats heat up quickly and become effective enough to pass EPA standards.

A tuner might be able to tune out this high rpm/high fuel load at cold start but I wouldn't suggest do it unless you are willing to run with no cats.
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2016 Camaro 1SS Hyper Blue 6MT NPP

2010 Camaro 2SS Cam/Headers/CAI/3.91 gears
476 rwhp/440 rwtq (sold)
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