Custom NPP Exhaust! While keeping Valves! Cost friendly Option
 

Finally did my exhaust

Exhaust :

Secondary Cat Delete : Custom Pipe extended Midpipe
Midpipe: FlowMaster 81083
Muffler : FlowMaster 8430152
Valve : Stock NPP ( cut and welded )
*EDIT* TIP ( decided to swap the stock tips ) : Flo-Pro Universal 2.5" ID / 4.5" OD / 7" Length

Issues : Stock valves rattle. It was doing that with stock NPP. I need to epoxy the pin.

Comments : I like it . Don't love it to say. It's really really deep . If you do not have the secondary cat delete there's no drone at all. I have slight drone in tour mode at 1400-1600 rpm .. at 70mph it's fine .. from 60-65 mph there's a slight drone. If you put it in sport mode .. it's really loud! I mean really loud. Vibrates the ear drums lol.. same amount of drone at cruising speeds because the valves close at cruising speeds. Safe to assume it will drone with valves being open at cruising speeds ..

Fix : adding a Jpipe to get rid of the drone. Should improve it. I have seen another member make that comment and it fixed the drone according to him. we shall find out after i install the JPipe

Cost:
MidPipe $300
Mufflers $160
Tips $90
Install $250
Total : $800

So overall I can say not bad to spend $800 total with install for full Catback Exhaust while keeping the NPP function


https://www.instagram.com/p/BS4dzlYj9Of/


https://www.youtube.com/watch?v=0KBVm6-KMhA


EDIT 12/30/2017 : ***NEW VIDEO****

https://www.youtube.com/watch?v=0W8P-v2ejWE

Not my picture .. but I have the same exact setup

http://i66.tinypic.com/11rxjti.jpg

Here's how the Jpipe would be installed ( NOT MY PICTURE )

https://image.ibb.co/dc5KP5/20988001...41346681_n.jpg

so you have 2- 1 into 2 mufflers the simply valved one of the outlets? that doesn't really work like npp if so as both outlets have equal muffling and where npp is basically a cut-out that bypasses the muffling effect when the valve opens

correct me if I am wrong on how yours works

The exhaust tone changes by a lot once the valve is open vs closed. But yeah this muffler has 1 inlet and 2 outlets. when one inlet is closed it sounds like what stock NPP sounds with valve open. Once the valve is open its really loud.. so it does the NPP function. Has 2 exhaust notes.. the whole point of NPP on stock system is to go from mild to wild sound. This route allows you to do the same thing. if you go towards end of the video you can hear the difference ..

i will try to make anther video showing the sound difference with valve open vs valve closed.

What does the NPP valve bypass? I fail to see it unless these are like the stock muffler and the valve bypasses internal baffling

what it does it closes off one outlet. when both outlets are open it gets a lot louder.

The muffler is 3inch in and 2 x 2.5inch out, when its closed he effectively has a 2.5 inch exhaust system, when its open its a 3 inch system with quad 2.5inch exits

although it appears to go through the same baffling, it actually doesnt. there was a cut away done a while back to help explain but its essentially a straight through pipe when its open

Thanks for posting! I think it sounds pretty good! I just received my Flowmaster's from Summit Racing yesterday. Cost was around $150.00 I have an appointment to have them installed tomorrow. Can't wait to hear how it sounds! :)

have them build a custom J pipe .. i wish i had when the car was on the lift lol .. there is drone when valves are open.

Yes on the factory NPP if the valves open exhaust flows thru the outside tips bypassing the muffler internal baffles. I was asking the OP what the valves bypassed in this setup he has made. It appears it simply adds an additional port to let exhaust escape the exhaust flows thru the same internal muffler baffles regardless of valve postion.

correct, in his case its simply switching from 2 tips muffled to 4 tips muffled

He didn't rev it. I wonder why he didn't rev it. Anyone know why he didn't rev it?:iono:

Maybe he should have revved it