BetterMostC6

Just drill a hole in the bottom and pull some packing out. Use muffler tape or bondo or even a rubber plug to cover the hole.

glennhl

How about a poor man's NPP? On the sectioned muffler, I'm assuming the inlet is on the top right and the outlet is on the bottom left. If I'm wrong, please correct me.

So why not punch a hole in the back chamber of the muffler and either weld in a manual cutout or if you want use an electric cutout? Wouldn't you then have a pretty straight shot through the muffler. Does anyone have a cross section of the NPP muffler?

gimmie_one

I have heard that the flowmaster is more restrictive than the magnaflow. The flowmaster is also somewhat louder. Someone correct me if I'm wrong as I'm no expert on the subject.

ben dover

In the good old days we used to drive for 30 - 45 mins to get the exhaust sys. plenty hot, and then squirt cold water into the mufflers to fracture the fiberglass. It made a noticeable difference and it's cheap to try.

From C6ZO62C8

nice, that looks restrictive, I'm suprised that with an exhaust swap you only get about 8 HP, after seeing this I would think that you would get more.

thanx for the pics

talon90

That is correct. That is the Z06 butterfly control fuse.

VET4LES

In the old days fiberglass mufflers got louder as they got older and the fiberglass deteriorated. Has fiberglass improved or maybe the stock system will get louder with time?

trivette

I wonder about the 'louder with time' theory also. I know my '84 that is totally original with 19,000 miles is definitely louder than when new. Most of the miles on it have been highway which may contribute to 'blowing out' some of the system. I don't really know what the '84 muffler is composed of internally-baffles w/fiberglass or? My '05 with 10,000 doesn't seem any louder than new despite probably 6,000 of them logged on trips plus a number of autocrosses. I keep contemplating doing something to improve the sound but am too cheap to do an entire system when there is for the most part a negligible HP gain to be had from it. If anyone experiments and has results from the drilling/removal of 'glass material it would be good to hear their comments.

glennhl

I think my 06 has gotten louder. Not only that, but I notice a drone at 1500 rpm (A6) if I'm going up a slight grade. I never noticed that before.

So does anyone have a cutaway of the NPP. I'm getting very interested in my proposed mod of cutting a hole in the back chamber. I think you can do the NPP mod for a couple of hundred dollars instead of $1200.

VET4LES

I hope your right, keep us posted.

mracer

I would bet if anyone were to muck around with the stock muffler's, like taking strands of fiberglass out, the Drone Monster would rear it's ugly head? Look how many here on the forum pay good money for aftermarket exhausts, only to put them up for sale after driving with them for awhile?! Why, feedback on drone, and some too loud to.
ymmv
Mike
PS: But I'd still like to see someone do it.................

cclive

I've heard a number of people say that the car is slightly louder than it was to begin with, but not many cars on here ever get enough miles for this to matter. I think its probably more miles than time that matters...

dkrhardy

I did the exact swap that Ozone did, and I will tell you that the Magnaflow's do get louder!

F40

npp mod for $200? I would like to hear more on this

ufaj26

This is true. I have almost 17k on my 08 and it is some louder. But just a little more noticeable. It won't get much louder overall

cclive

And on this forum, 17K on an '08 puts you far out at the end of the annual mileage curve!

BigJoe

Gad, no kidding. I just turned 22,000 on my 2005 and I don't notice it being any louder than the first day I drove it.

sd455ta

Does anyone know who make the Corvette mufflers?

It most likely is one of the big manufacturers.

Why not sent that cutaway pic to their engineering department and ask them what can be done to improve the exhaust sound.

Or better yet sent it to Ferarri exhaust engineers for some ideas.

If that does not work, someone with a welding outfit could, peel back part of one or both sides, open up some larger holes in the perforated tube section, remover some filler and weld it up again. Very cheap and easy to do.


I think their would be lots of interest in a simple, inexpensive muffler modification to improve the sound level, while maintaining the stock system!

Any sheet metal hobby guys out there?

Rich

PS: I do not have a welding outfit or I would do it myself!

glennhl

Walker make the OEM mufflers.

Weely

Is the pipe at the top of the photo where the exhaust gas goes into the muffler or goes out of the muffler?