As Haro already stated, And very correctly. Individual parts of the Bosal system are not sold. Why??? Because its a one piece system. Emphasis on the system part. They are Not the same as any other Bonneville muffler. The one piece exhaust System by Bosal uses their patented Exhaust Wave Technology. They make alot of OEM systems for a host of car makers. The technology is used on OEM high performance cars and trucks, plus they sell aftermarket systems for alot of others. The System makes the sound you hear, Not just the mufflers.I will copy/paste the concept below from the manufacturer.

1. Escaping exhaust gas creates pressure wave moving down the system.

2. Wave hits the system’* end, causing “suction wave” to travel back up the system.

3. Suction wave hits the cylinder and reverses direction just as the exhaust valve opens.
The suction wave helps pull exhaust gases from the cylinder improving engine breathing and volumetric efficiency.



The system is unique to the GXP, when You cut the exhaust up, replace mufflers, change tips, Etc., You are screwing up a design made to make the Northstar run at it'* peak game, considering the limitations imposed. .Just one of alot of reasons I have stated over and over again here for 2 years. The Northstar system is engineered to get the best of what can be gotten out of it, considering the limitations GM put on it. Unless we find aftermarket that will overide the engineering already built in. You are wasting your time. And possibly making the car slower.

Thanks for the info Venom. Based on this information, it does appear that the the bosal system is a well-designed semi-performance system. I say semi-performance because the OEMs typically put noise reduction at a higher priority than performance. No matter how well designed the system, it has to meet a certain noise standard as determined by the marketing dept. based on the target demographic for the car (and the federal standards as well). Therefore, I still do believe there might be a performance improvement available by going to aftermarket mufflers. It is very difficult for a muffler to remove the low-frequency output without relatively high levels of backpressure.

At the moment, I have no intention of running out and installing aftermarket mufflers, knowing that the odds of a significant improvement in performance are not very promising.

I hear ya Turbo, and yes I'm am sure if a turbo or supercharger were fitted successly to the car to cause signifacant boost, it would indeed be beneficial to modify the exhaust. But given the present parameters for modding a GXP, I think it best to leave the stock intake/outake alone. Until I found more about the Bosal system, I was ready to replace the OEM with aftermarkets when the OEM'* wore out. But know I will buy the OEM replacement when needed. I always scratch my head and wonder if these type of systems work, but given the great sound the GXP has for a stock engine, I think it does. Even at WOT with nitrous they seem to get the job done. I think a flow issue could certainly show itself under those conditions.;

I dunno, I've been extremely satisfied with my Magnaflow'*.

I gained some rwhp on the dyno and more importantly, some torque, on average an extra 1.5 mpg per tank of fuel, overall smoother acceleration, and normal acceleration in traffic, I never see over 2,200 - 2,300 rpm. I know that doesn't mean much, but in trying to be economical with fuel and fuel costs (as mine is a DD), less rpm for the same level of acceleration, means less fuel consumption.

Best yet, it sounds MUCH better! WOT is simply orgasmic. The only thing better is my open system, catless GTO.

The Bosal OEM mufflers are great for a stock muffler (and certainly better than most GM mufflers), but they are an OEM piece which is meant to fulfill many tasks (IE: compromise), not just performance. Our system is pretty straight forward in terms of layout, but there are areas for improvement.

CMNTMXR57, You could well be right, I just came up with that tidbit of info searching for why the components were'nt available by the piece. It could be that magnaflows cut back pressure enough to offset what Bosal has engineered. And as you said, it is a great setup for OEM stock. I am a lazy sort and for 5 and some change, I rather just stick to OEM. I cant see it making a big difference in performance, and I like the sound as is, and a one piece replacement suits me fine.

You wouldn't happen to have pics of the whole system on the car, would ya?

Aaaaah, nope. Sorry but it'* 13 degrees out and 'bout a foot of snow on the ground. Even though I can raise mine almost 2 feet off the ground. Its not photo op weather.