Exhaust
Pro
Joined: Dec 2004
Posts: 565
Likes: 8
From: La Jolla California
Drifting
Joined: Jan 2005
Posts: 1,556
Likes: 276
From: Marshall Texas
The two outer tubes are the unmuffled tubes. If you have your NPP set to the unmuffled that is the reason those are the ones that get dirty.. Love the sound, especially around 4-6 thousand RPM's.... 
Pro
Joined: Dec 2014
Posts: 573
Likes: 12
From: Pleasant Hill MO
Instructor
Joined: Jul 2014
Posts: 206
Likes: 2
From: PA
I think that the exhaust "soot" is carried out of the exhaust by condensation especially during warm up. I think that if you drive with the NPP closed until the car is up to temp and condensation is lower, you get less soot "drips" on the trumpets. At least it has been my experience.
Drifting
Joined: Apr 2013
Posts: 1,743
Likes: 453
From: Saint Clair Shores Mi
I pulled the fuse for the NPP so the flaps are always open - It sounds great, but the outside trumpets get pretty dirty very quickly even on short drives. I just use a damp paper towel followed by a dry one to clean them up. Every couple weeks when I do a touch-up wax I use the cone tool to clean all the crap out of the perforated inner pipes. A bit on the **** side maybe, but it really bugs me when they a black and sooty.
Intermediate
Joined: Apr 2015
Posts: 42
Likes: 1
I pulled the fuse for the NPP so the flaps are always open - It sounds great, but the outside trumpets get pretty dirty very quickly even on short drives. I just use a damp paper towel followed by a dry one to clean them up. Every couple weeks when I do a touch-up wax I use the cone tool to clean all the crap out of the perforated inner pipes. A bit on the **** side maybe, but it really bugs me when they a black and sooty.
Burning Brakes
Joined: Feb 2015
Posts: 1,077
Likes: 266
From: TN
Exhaust
Use Easy Off oven cleaner on them. Just be careful not to get it all over. Spray the tips and let sit for a few minutes and then wipe off. You'll be able to eat off them after. Used that on my quad tips on my SRT and they come really clean.
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Safety Car
Joined: Jan 2015
Posts: 3,941
Likes: 499
From: Northern Virginia
Fuse 32 controls the AFM (4 cylinder mode) exhaust valves. Pulling that fuse will throw a CEL.
If you have an automatic, the car will go into AFM mode and close those valves often, and when those close the exhaust gets quieter regardless of whether the NPP valves are open or not. There isn't much you can do about it except get a tune which disables 4 cylinder mode, or keep the transmission in manual mode (which prevents AFM operation).
If you have an automatic, the car will go into AFM mode and close those valves often, and when those close the exhaust gets quieter regardless of whether the NPP valves are open or not. There isn't much you can do about it except get a tune which disables 4 cylinder mode, or keep the transmission in manual mode (which prevents AFM operation).
Drifting
Joined: Apr 2013
Posts: 1,743
Likes: 453
From: Saint Clair Shores Mi
Which fuse do you pull?
On the 2015 with NPP, there is the #42 fuse marked something akin to Exhaust #2 and the #32 fuse Exhaust #1.
Pull one or both of these?
Someone on this forum once said to pull front box fuse #42.
So I pulled #42, but it did not make much difference.
What does #32 do?
On the 2015 with NPP, there is the #42 fuse marked something akin to Exhaust #2 and the #32 fuse Exhaust #1.
Pull one or both of these?
Someone on this forum once said to pull front box fuse #42.
So I pulled #42, but it did not make much difference.
What does #32 do?