Hey Guys!
so i have been doing alot of thinking about exhaust systems and i really want to get the most gains possible.
i want to straight pipe everything under the hood. cats and all.
the only thing i would like to keep under there is the muffler for the sound aspect but get rid of the cats all together.

i have seen alot of guys talk about it, and everyone says dont do it because of the "required" back pressure!?!?!
what the hell does that mean? isnt the optimal flow out of the exhaust the most ideal solution anyways?
what is the whole deal, it makes sense to unrestrict the flow as much as possible. or am i out to lunch!?!?!

thanks in advance!

 

Car engines are 4 stroke cycle engines. Out of these 4 strokes, only one produces the power, this is when the explosion occurs and pushes the pistons back. The other 3 strokes are necessary evil that don't produce energy. They on the contrary consume energy. During the exhaust stroke, the remaining gas from the explosion is expelled from the cylinder. The higher the pressure behind the exhaust valves (i.e. back pressure), and the higher effort necessary to expel the gas out of the cylinder. So, a low back pressure is preferable in order to have a higher engine horsepower.

Yeah I copied that LOL, but I think you need a little back pressure to help the engine cycle. Our engine is designed with back pressure in mind. Ive heard that some people loose low end torque but gain torque on the top end with a dump. I think if you run long tube headers no cats and some good high flow mufflers it would be ideal for our trucks. But if its supercharged you would want as little back pressure as possible. I think in this case the boost helps the engine cycle.

 

cool thanks. im thinkin that i will take your advice and go with the long tube headers for sure!
thanks!

 

Yeah, depending on the engine, too little back pressure will kill low end torque. 5.3 and 4.8 (and so on) breathe very well and if too much backpressure is taken away it will cause the engine to loose power until the rpms pick up and the engine can benefit from the decreased pressure on the exhaust stroke of each cylinder. (That gave me a headache)

Its almost like the engine is moving too easily at low rpms to make full use of the gas charge when too much exhaust back pressure is taken away.

 

so JCBST 12 do you think that with a long tube headers combination and a high flow muffler there will still be enough back pressure to make the engine run efficiently and safely?! im buying the exhaust system within a few weeks but the headers will have to wait!

 

Long tube are supposedly the best for our trucks. Use a Y pipe and some sort of flowmaster or something like that and you'll be fine. You won't need a "high" flowing muffler, just a performance one.