1sc334

i heard a set of mufflers with the npp on them and my question is open wat are the difference between them n b&b bullets 06 dont have that option n the only ones that fit are ones from 08 unless i by a later model mid pipe so im just trying to get an idea of wat the bullets would sound like compared to an open npp exhaust

Gearhead Jim

A club member had the bullets on his car for one weekend, 'til his wife said she'd never ride in it again until he replaced them.

Driving behind him, his car with the bullets sounded far noisier than our NPP with the valves open.

saplumr

Bullets vs NPP = not even close!

hungryhippo

Even my b&b prt are louder than npp with the valves open.

JCtx

How can they be that much noisier (with just an axleback change) if mufflers get completely bypassed with NPP open??? NPP gets ear splitting loud at large throttle openings. And inside the car NPP drones pretty bad at certain rpm too. Having said that, I don't personally like the sound of NPP open very much, especially at low throttle openings, so I'm sure aftermarket systems can improve upon that. But maybe it's just GM's firing order, since my car has what looks like a very effective factory X-pipe., and still has the 'motorboat' sound.

saplumr

There is no posible way NPP is "bypassing" the mufflers. If you listen to Bullets or Xtreme you know the definite difference compared to NPP.

Orange05_C6

I have bullets on my 05.

Bullets = Best Sounding Exhaust Eva

Streetk14

Or you can get the B&B Fusions, which are a bi-mode like the factory NPP system -- but sound and look a lot better. They are really similar to their bullets when open, and pretty mild when closed (unless you have headers, a cam and no cats).

Orange05_C6

I was guna get the fusions but I realized, why spend so much more for something that I won't even use. I figured I'd keep them open all the time so I just saved my money and went with the bullets and super glad I did

Bill Dearborn

If you have ever seen the cut open Z06 mufflers you would have noticed the outlet with the valve is a straight pipe that goes directly to the inlet of the muffler so when the valve opens the muffler turns into a straight pipe. The older ones had holes cut in the pipe to let some of the exhaust pass through the muffled side but the newer ones have a solid pipe. The bullets are nothing but a straight pipe as well so from a power stand point they aren't any better.

Bill

saplumr

This is a long read but clearly states IF that is a fact, GM, is violating state laws.
http://www.gmhightechperformance.com...s/viewall.html

Seadawg

You lost me. Every state law I've seen is when the vehicle is at idle or up to 2500 rpms. NPP is not working at that RPM range.

If you bypass the exhaust, YOU are responsible, not GM. No different than anyone that has made car, truck or motorcyle exhaust systems "louder".

If you disagree, I recommend you start another thread, so we don't hijack this one any further.

saplumr

You're not paying attention. Someone said the GM's NPP bypasses the muffler so that would put GM in violation of state laws. Does that clear it up for you?

Gearhead Jim

To get technical, the NPP does not bypass the mufflers. The exhaust goes into the muffler and comes out of the muffler, no bypass.

Of course, nothing happens to the exhaust while it is in the muffler; but it did go through the muffler and did not bypass.

Detoxx03

NPP is the best exhaust option available in my opinion. I love the way mine sounds with the valves open and closed. Two of my friends had Corsa and one had B&B and now they all have NPP. Won't have drone either with NPP. Here is mine:

http://www.youtube.com/watch?v=2MPlN...e_gdata_player

JCtx

Can't you realize we're talking about NPP with VALVES OPEN??? Geez. In stock form they open at 3,500 rpm most of the times. But you can easily and cheaply add a switch to leave them open all the time, like if you had a louder axle back system. But you always have the option to quiet it down immediately if desired.

saplumr

You're right, being a plumber for 38 years I don't understand the basic fundamentals of opening and closing a valve. Sorry for my confusion.

3XBlack6spd

I had the NPP's on my car, pulled the fuse so they stayed open at all times. I've since replaced the whole exhaust, headers, X-pipe, and Bullets. I did just the Bullets first. Obvioulsy now it screams, and Drones like a mother! It was Way louder with just the Bullets too. The drone is a bit much. If you don't like drone, or noise, don't do bullets! I love it, and Think a car with a 427 should be a loud! But that's just me!

To sum it up.. NPP's do not compare to Bullets.

3XBlack6spd

By the way.. My NPP exhaust if for sale if you want it! Like brand new, pulled of my car (2008 Z06) with 4,000 miles. I'll take $600.

Divvi

Take it, that's a great price.