I have a 2002, so I don't know much about c4s. My father had to have some work done on his '95 automatic coupe, and while the exhaust is off he was considering having the large single muffler between the cats and rear mufflers removed. A muffler shop tech told him he might not want to do this, because it would negatively affect the car's performance because of loss of back pressure, and that it would make the car too loud.

Is this right??? Common sense would tell me that:

1. Since the car will still have OE cats and OE rear mufflers, it will not be that loud.

2. Since the car will still have OE headers, cats, and rear mufflers it will still have plenty of back pressure, in my opinion more than necessary.

Am I right in thinking this exhaust tech doesn't know WTF he's talking about? If it were my c4, not only would I get rid of the center muffler, I'd add long tube headers, high flow cats, and replace the OE rear mufflers with aftermarket mufflers. I would think that with after market mufflers and cats the car would still have enough back pressure for a 350ci engine to perform well.

Should my father have the center muffler removed? Price does not matter, even if it only adds a small amount of power.

THANK YOU for any responses!

(p.s. my c5 has B&B Bullets, so IMO, who needs mufflers? )

 

That part is the resonator and should not be removed. IF it must be removed, and x-pipe crossover should be in its place, at a minimum. C4 after market catbacks all have resonators or crossovers.

 

Why not? Can it really make the car that loud? C4s are pretty darn quiet as it is. Also, my c5 has no resonator from the factory, and I added a super-loud aftermarket catback, but the noise level is still pretty mild in the interior with stock cats and exhaust manifolds. What is it about the c4's motor that would make it too loud without the center resonator? Sorry, I really know absolutely nothing about c4s or LT1 motors.

 

Resonance is an issue with these cars it can get pretty loud inside with the cat back system upgrade. I have a Power Effects
system on mine( can't buy it anymore) that has 6 adjustments on the muffler and it still resonates pretty loud at certain RPMs. I can't imagine how loud it would be without it but I do not wanna. If he does any long distance driving I am sure it would be unbearable. The X or crossover pipe is supposed to help eliminate some of it but I would still keep the resonator. It is sort of a glass pack on my system as the mufflers can be set to straight through setting.

 

I wouldn't worry about it but I would definitely add an X pipe or crossover if he does eliminate it. Before I installed my PE system, I had a stock LT4 system. These are just like the LT1 system except they have a crossover. With headers and no cats, it was louder than stock but no resonance. And it sounded great! I also added a crossover to my PE system. The resonance is not too bad on this system with the mufflers on the quietest setting. The crossover didn't make a noticable change in resonance around town but on the highway, I can hardly hear it now above 64-65 MPH. The crossover smoothed out the sound too and added a very noticeable improvement in response in the low and mid range.

 

Note that when I removed my mufflers, I actually lost power. Not noticable in daily driving, but the timeslips don't lie at the track.
I lost about 1.5-2 mph. When I installed the Corsa, I got that mph back.