We have the V10 6.8L in our '03 Excursion and when we looked at the exhaust wand notice it wasn't welded . So we experimented by unbolting the last half of the exhaust so the cats are still on, and we like the sound better than the flow masters. And we went to radio shack and borrowed their decible meater. It was 98bd under the truck and legal is 92 bd, so as far as loudness goes we shouldn't have any probs for being to loud. So my question is how is the performance affected by having no muffler on the truck and what is it affecting, like horse power, torque, gas milage, and what ever else you can tell me. Thanks!!!

 

As long as you keep the Diameter down and the same length as stock, you shouldn't have any significant negative effects. If you increase the diameter of the pipe, it will change it's resistance to airflow and you will either make more pressure or you will start sucking in air and slowing exhaust flow.

The muffler attenuates certain frequencies, either by absorption or by reflection. There should be minimal changes in velocities between the input and output of the muffler.

 

The pipe are still stock we just disconected the jiont in the pipes after the cats and want to leave it like this unless it is going to destroy the engine or decrease gas milage. Are there any benefits??

 

Its been proven over and over a "tuned exhaust" or even a "semi tuned exhaust" will get better mileage.
Actually on the V-10 you may loose a little HP, but on the other hand a little gain in toque at lower RPM due to less back pressure.

 

CC. you don't have any exhaust after the cat? is that what you are saying? if so then you might have problems with fumes. Especially when sitting at red lights or just parked.

 

when we got our lift the guys cut our exhaust and put on a tube that is about 12-15 inches long connected to the muffler that curvered down, like what you see on trophy trucks, and our neighbor said that he could cut off the pipe from the muffler and weld it onto the exhaust if we decided to keep but i want mak sure we aren't hurting the engine and causing damage by removing the muffler. On average how much is it to get a dyno, so i can see the power diff??

 

Dyno runs cost $50-$100 and usually get you 3 or so runs back to back.