ZF Six

Posted in Z06/ZR1 as well...

I can only find one picture of a muffler-mod NPP exhaust with 4" tips but it's off the car and I want to see what something like this looks like installed.

I have stared at the back of my car and tried to envision 4" tips on the factory NPP and my concern is that they would hang too low.

Has anyone done this and do you have pictures?

Thanks,
Stephen

Turbo6TA

As you more than likely know, the NPP polished stainless steel muffler tips are welded on the the short piece of pipe that contains the NPP valves.

I guess you could cut that section of the tips off and weld in a different tip .... but to me, it would not be worth the trouble.

ZF Six

Yes, they make short enough tips for this to work. The factory tips are too small.

Shaolin Crane

I saw somewhere someone replaced the tips when using the mufflers on a C4, but naturally can't find it now

ZF Six

I ordered a set of larger tips so I'm just going to do it and see how it looks.

Turbo6TA

I have a set of the older style Borla 'Touring' (Type 1) mufflers on my GS.

The tips are 4.25" x 3.5" oval (that's about the widest tips I have found for our cars)


Attachment 48332457

ZF Six

I did it, looks pretty good. I do wish the whole system was tucked up tighter but you would have to cut the hangers off and re do everything and I didn't think it was worth trying.

This is how they look straight out of the box so I'm sure I can polish them for a better shine.

iwantaz06now

Zfsix where did you get the tips? Did they effect the sound or popping of the original exhaust?
My corsa x pipe would compliment your ride perfectly

ZF Six

I made a thread about it here: https://www.corvetteforum.com/forums...-npp-pics.html

Sound was not changed, still pops under decel. I have a Corsa X-pipe on the way

FatsWaller

About the popping: I guess like the rest of us with NPP, this is very noticeable on decel, particularly if you downshift to use engine braking, I'm kind of surprised that the car does this; from my 'old school' experience, the popping is backfiring from unburnt fuel igniting in the exhaust. Is that what's happening here? I would have thought with all of the computer driven stuff, the injectors would just shutdown under decel, so there should be no fuel getting sucked in. Or is this a case of residual fuel in the intake runners getting sucked in?

iwantaz06now

There is a delay built into the system that helps provoke the popping when letting off the throttle. I forgot the official term for it. Off throttle popping can also be influenced by the axle back system you use. 2011+ Z06 use the ZR1 mufflers. Prior versions of the Z06 had a different internal muffler design that do not pop as much if at all.

Shaolin Crane

Popping and burble on decel is also backpressure/flow related as well. It is also sometimes caused by a buildup of moisture too.

SixAddict