Npp valve actuator mod.

KingLT1 · 10-06-2020, 06:57 PM

Today I decided to mod the NPP actuators on my exhaust per the latest TSB that is suppose to fix the "rattle". I never noticed much rattle with my Flowmaster NPP but I wanted to try it to see if it would help the valves seal better when closed.

It requires using a cut-off wheel and cutting off the ears on one side of the actuator.
https://www.camaro6.com/forums/showthread.php?t=556061

Surprisingly this really works. The exhaust note sounds cleaner when closed and even notice a difference open. I highly suggest doing this no matter what type of NPP exhaust you have. Thanks to 6spdHyperblue for mentioning this a while back!!

arpad_m · 10-08-2020, 09:11 PM

Quote:

Originally Posted by KingLT1

Today I decided to mod the NPP actuators on my exhaust per the latest TSB that is suppose to fix the "rattle". I never noticed much rattle with my Flowmaster NPP but I wanted to try it to see if it would help the valves seal better when closed.

It requires using a cut-off wheel and cutting off the ears on one side of the actuator.
https://www.camaro6.com/forums/showthread.php?t=556061

Surprisingly this really works. The exhaust note sounds cleaner when closed and even notice a difference open. I highly suggest doing this no matter what type of NPP exhaust you have. Thanks to 6spdHyperblue for mentioning this a while back!!

King, did you perform this on both the driver and the passenger side valves?

KingLT1 · 10-09-2020, 08:27 AM

Quote:

Originally Posted by arpad_m

King, did you perform this on both the driver and the passenger side valves?

Yep.

arpad_m · 10-09-2020, 12:07 PM

Quote:

Originally Posted by KingLT1

Yep.

Thanks. Now I have a new little weekend project

Aaron07 · 10-09-2020, 03:48 PM

Will the dealer do this at no charge?

arpad_m · 10-11-2020, 07:12 PM

Project completed, valves still work (phew). I haven't yet driven the car since the mod, so I can't comment on improvement, if any.

One thing's for sure, though, a Martian with skinny, 10" fingers would have a much better time working on this stuff

Of course I could've dropped the exhaust to make room, but come on.

Aaron07 · 10-12-2020, 12:34 AM

Quote:

Originally Posted by arpad_m

Project completed, valves still work (phew). I haven't yet driven the car since the mod, so I can't comment on improvement, if any.

One thing's for sure, though, a Martian with skinny, 10" fingers would have a much better time working on this stuff

Of course I could've dropped the exhaust to make room, but come on.

Had a chance to drive it yet?

KingLT1 · 10-12-2020, 08:53 AM

Quote:

Originally Posted by Aaron07

Will the dealer do this at no charge?

There is a TSB for it, so they should of you have the rattle but they only do the passenger side.

arpad_m · 10-12-2020, 02:19 PM

Quote:

Originally Posted by Aaron07

Had a chance to drive it yet?

Not yet, it's been raining since yesterday evening, forecast is the same for tomorrow, I just used the family SUV. Will post back with findings.

The rattle on mine wasn't super bad, but you know how it is, our butts can't stay put with an open TSB and tools waiting to be handled

arpad_m · 10-14-2020, 04:40 PM

Quote:

Originally Posted by Aaron07

Had a chance to drive it yet?

Okay, after driving the car about 15 miles, tinkering with settings while paying specific attention to the exhaust, the fix seems to have really worked. Might be placebo, as I didn't measure anything with instruments, but the exhaust note is now much "cleaner", same tone but fewer "disturbances" both with the valves shut and open, it feels as if the exhaust was new again. Hope this makes sense.

One can only wonder how the GM engineer in charge of this came up with the idea for the fix

KingLT1 · 10-15-2020, 06:50 AM

I wondered the same thing. Lol

DarkMaroSS · 01-21-2022, 09:38 PM

Quote:

Originally Posted by arpad_m

Project completed, valves still work (phew). I haven't yet driven the car since the mod, so I can't comment on improvement, if any.

One thing's for sure, though, a Martian with skinny, 10" fingers would have a much better time working on this stuff

Of course I could've dropped the exhaust to make room, but come on.

Doing this on both actuators along with tuning the valves with HPTuners worked like a charm and the sound in high rpm’s is nice!

biker2k · 01-22-2022, 07:52 AM

how do you tune the valves with hp tuners

WillyZ83 · 01-22-2022, 09:56 AM

Anyone know if the TSB is still applicable for the 2021 1SS?

10-06-2020, 06:57 PM	#1
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,797	Npp valve actuator mod. Today I decided to mod the NPP actuators on my exhaust per the latest TSB that is suppose to fix the "rattle". I never noticed much rattle with my Flowmaster NPP but I wanted to try it to see if it would help the valves seal better when closed. It requires using a cut-off wheel and cutting off the ears on one side of the actuator. https://www.camaro6.com/forums/showthread.php?t=556061 Surprisingly this really works. The exhaust note sounds cleaner when closed and even notice a difference open. I highly suggest doing this no matter what type of NPP exhaust you have. Thanks to 6spdHyperblue for mentioning this a while back!! __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

10-11-2020, 07:12 PM	#6
arpad_m Drives: 2018 Camaro 2SS A8 Join Date: Jul 2017 Location: East Tennessee Posts: 11,603 View My Garage	Project completed, valves still work (phew). I haven't yet driven the car since the mod, so I can't comment on improvement, if any. One thing's for sure, though, a Martian with skinny, 10" fingers would have a much better time working on this stuff Of course I could've dropped the exhaust to make room, but come on. Attached Images __________________ 2018 Camaro 2SS — G7E MX0 NPP F55 IO6 735 rwhp \| 665 rwtq Magnuson TVS 2300 80mm pulley \| Kooks 1 7/8" LT headers \| JRE smooth idle terminator cam \| LT4 FS & injectors \| TSP forged pistons & rods JMS PowerMAX \| DSX flex fuel kit \| Roto-Fab CAI \| Soler 95mm LT5 TB \| 1LE wheels \| 1LE brakes \| BMR rear cradle lockout \| JRE custom tune 1100 - 1/30/18 \| 2000 - 1/31/18 3000 - 2/06/18 TPW 2/26/18 3400 - 2/19/18 \| 3800 - 2/26/18 4300 - 2/27/18 \| 4B00 - 3/01/18 4200 - 3/05/18 \| 4800 - 3/14/18 5000 - 3/16/18 \| 6000 - 3/19/18

10-15-2020, 06:50 AM	#11
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,797	I wondered the same thing. Lol __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

01-22-2022, 07:52 AM	#13
biker2k Drives: 2018 2ss 1le Join Date: Jan 2018 Location: Huntington, NY Posts: 474	how do you tune the valves with hp tuners __________________ 2018 2ss 1le roto fab dry, Stainless works 1 7/8 lt to 3'" x pipe with highflow cats to stock npp, soler 95mm t/b, edelbrock 2300, LT4 fueling , jms bap and dsx flex fuel, 618/620 on e45 rwhp Jannetty Motorsports tuned

10-09-2020, 03:48 PM	#5
Aaron07 Drives: 2017 2SS F1FTY Join Date: Feb 2020 Location: Fort Wayne, IN Posts: 347	Will the dealer do this at no charge?

01-22-2022, 09:56 AM	#14
WillyZ83 Drives: 18 zl1 garnet red Join Date: Aug 2021 Location: TX Posts: 287	Anyone know if the TSB is still applicable for the 2021 1SS?

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