NPP Exhaust not working?? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

NEVRL8 · 01-04-2014, 06:44 PM

OK, my NPP is open at idle, closes just off idle but will not open back up under acceleration. I have ran the RPM up to 5K and they flaps still don't open. I did this while in neutral in the garage. Does it have to be in gear and actually moving to operate properly? I've drove it but can't tell if it's opening for sure by sound. ??????

Iam Broke · 01-04-2014, 08:19 PM

Yes, engine has to be under load for the manifold vacuum to drop and allow it to open.

NEVRL8 · 01-04-2014, 08:30 PM

Quote:

Originally Posted by Iam Broke

Yes, engine has to be under load for the manifold vacuum to drop and allow it to open.

Thanks! Makes me feel better. I thought it was broke.

Iam Broke · 01-04-2014, 08:52 PM

Fuse pull will keep it open.

h018871 · 01-04-2014, 11:41 PM

Quote:

Originally Posted by NEVRL8

OK, my NPP is open at idle, closes just off idle but will not open back up under acceleration. I have ran the RPM up to 5K and they flaps still don't open. I did this while in neutral in the garage. Does it have to be in gear and actually moving to operate properly? I've drove it but can't tell if it's opening for sure by sound. ??????

If you have the factory dual mode exhaust (NPP), it is triggered by engine speed and throttle position. So in neutral and rev up to 5000rpm most likely won't cause the flaps to open. If you want to see in your garage, have a friend stomp on the accelerator fully and you should see the flapper open as the revs pass 2000 to 3000rpm. Be sure your friend gets off of the accelerator before redline. The rev limiter should kick in, but you never know.

NEVRL8 · 01-05-2014, 06:42 PM

Quote:

Originally Posted by h018871

If you have the factory dual mode exhaust (NPP), it is triggered by engine speed and throttle position. So in neutral and rev up to 5000rpm most likely won't cause the flaps to open. If you want to see in your garage, have a friend stomp on the accelerator fully and you should see the flapper open as the revs pass 2000 to 3000rpm. Be sure your friend gets off of the accelerator before redline. The rev limiter should kick in, but you never know.

Thanks, I got everything working now.

01-04-2014, 06:44 PM	#1
NEVRL8 Drives: 2013 Victory Red 2SS/RS Join Date: Nov 2011 Location: TX Posts: 307	NPP Exhaust not working?? OK, my NPP is open at idle, closes just off idle but will not open back up under acceleration. I have ran the RPM up to 5K and they flaps still don't open. I did this while in neutral in the garage. Does it have to be in gear and actually moving to operate properly? I've drove it but can't tell if it's opening for sure by sound. ??????

01-04-2014, 08:19 PM	#2
Iam Broke PHAT B33 Drives: 2012 TF3 Camaro 2SS/RS M6 Join Date: Jun 2012 Location: Dark of the Moon Posts: 1,460 View My Garage	Yes, engine has to be under load for the manifold vacuum to drop and allow it to open. __________________ Another 1 of 371 '12 T3 LS3 M6's built.

01-04-2014, 08:52 PM	#4
Iam Broke PHAT B33 Drives: 2012 TF3 Camaro 2SS/RS M6 Join Date: Jun 2012 Location: Dark of the Moon Posts: 1,460 View My Garage	Fuse pull will keep it open. __________________ Another 1 of 371 '12 T3 LS3 M6's built.