One thing I've kind of always wondered, what harm can come from straight piping a vehicle? I've never really been sure.

 

nothing. it will be louder that's about it. my 75 is straight piped, has been for 20 years.

 

Nothing really. Late model vehicles are slightly different with the PCM and cats or what not, would throw a cel code but anything in this gen section you be absolutely fine.

Just make sure you dont have emissions checks in your area though, straight piping means deleting the cats and prob wouldn't pass any emissions checks with that.

 

I mean I knew about it being louder. But I've heard people say it's bad on the engine to run them like that. I've always wondered because I've never been told for sure

 

that is true for older vehicles but not newer ones. saw lots of 4.6l cars come in with drive-ability issues because they no longer had any back pressure. the newer cars are tuned to work with the back pressure that the cats and mufflers provide. so i guess it really depends on the vehicle

 

One good thing about where I live, no emissions checks

 

Its not so much a back pressure idea but lack of exhaust velocity. If you use too large of an exhaust opening the gasses move slowly. Like using a large garden hose instead of a nozzle. Exhaust works in pulses ( in and out ). The out pulse counters the in pulse from another cylinder. This is called scavenging. If there is low velocity the scavenging doesn't happen and the exhaust gets sucked back into the cylinder displacing air fuel mix and limiting power. This happens most at low rpm cutting torque. Higher rpm eventually increases exhaust velocity. The balance , y, x, or h pipe issues the pulses from the mated cylinders on the opposite side to balance the pulses and increase scavenging. The O2 sensor is placed in the balance tube and calibrated to read both banks at that location ( unless you have 3 sensors ) Another issue with fuel injection is the slow gasses causing s false reading at the O2 sensor. Finally if you have a 96 or newer removing the cat will cause an error code in the system causing the ecu to operate failsafe. Aside from all that the exhaust smells rich and releases poisons gasses that , because of the shape of the truck, are sucked back toward the drivers compartment. The ideal setup on a v8 if you can make it fit is to run an x pipe from long tube headers. Have the O2 sensor appropriately placed. Run a set of high flow cats into some high flow mufflers then dump before the rear axle. 2 1/2 " twin pipes is usually the best size for a 5.0. I personally just ran a 3" single pipe after the factory cats with shorty headers and a 3" chambered muffler. It is throaty without an irritating drone on the freeway and I picked up quite a bit of torque and still emissions legal. BTW just for information, it is against federal law to remove or disable any emissions systems even if your state has no checks. That means you can get a ticket or loose you vehicle if someone decides to be a jerk about it. State police can enforce Federal law. Just ask the guys out here in California trying to sell medical marijuana.

 

you always make these kind of comments. makes me think you are a tree hugger. i dont care whats legal and what aint cuz out here in the middle of nowhere there aint nobody gonna stop me

 

just fyi, the o2 after the cat does not effect how the engine runs, it just lets you know when the cat is bad.

 

There's only one o2 on my truck and it's before the first cat