Putting dual exhaust on a straight 6?
#2
#3
ehh, it depends on what you think "sounds good". I've been around a 300 with true duals ran on it and i thought it sounded horrible, it sounded like two 3 cylinders trying to race one another.
Of the setups i've had (stock 2 cats and a muffler, 2 cats and no muffler, 1 cat and no muffler, open, and no cats and a flowmaster 40) I like the 300 through a big single (2.25-2.5) and a catalytic converter the most. It has a presence but isn't loud unless you really want it to be.
Justin
Of the setups i've had (stock 2 cats and a muffler, 2 cats and no muffler, 1 cat and no muffler, open, and no cats and a flowmaster 40) I like the 300 through a big single (2.25-2.5) and a catalytic converter the most. It has a presence but isn't loud unless you really want it to be.
Justin
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#8
You can actually get a pretty good idea of how big of a pipe you need if you know your compression ratio, max RPM, volumetric efficiency and CID. you figure your flow into the motor with CID, VE, and RPM and then using your CR you can get a good idea of the flow out of your motor. Then the easiest way is to look in a pipe fitters manual which will give the maximum acceptable flow through a certain diameter pipe. you want to use the smallest diameter possible that will still flow what you need it to SINCE. . .
Allright, here goes.
Back pressure is never good. Motors always run the best and make the most power when the exhaust is sized to give no back pressure, but is small enough to maintain exhaust velocities (laminar flow).
If the pipe is too big the exhaust escapes from the port very quickly, but looses steam as it heads down the pipe. It eventually slows and creates a turbulent flow as more exhaust tries to fight past it which creates backpressure within the exhaust that creates a loss in power.
Now, the back pressure created by turbulent flow is greater than the backpressure created by a slightly too small pipe which maintains exhaust velocities. A slightly too large pipe is worse for performance than a slightly too small pipe. This typically manifests itself at lower RPM's where alot of times guys notice they "have no torque" after installing headers, but they pull up top like nothing else. At high rpm's the velocity in the headers is manitained by increased flow, but at low rpm the exhaust just sits in there.
Pretty much if your motor is stock, don't go too much above factory. On a stock 300 dual 2's or 2.25's would be all the more the motor could use, anything above that just makes it louder and starts to hurt your down low power.
Justin
Allright, here goes.
Back pressure is never good. Motors always run the best and make the most power when the exhaust is sized to give no back pressure, but is small enough to maintain exhaust velocities (laminar flow).
If the pipe is too big the exhaust escapes from the port very quickly, but looses steam as it heads down the pipe. It eventually slows and creates a turbulent flow as more exhaust tries to fight past it which creates backpressure within the exhaust that creates a loss in power.
Now, the back pressure created by turbulent flow is greater than the backpressure created by a slightly too small pipe which maintains exhaust velocities. A slightly too large pipe is worse for performance than a slightly too small pipe. This typically manifests itself at lower RPM's where alot of times guys notice they "have no torque" after installing headers, but they pull up top like nothing else. At high rpm's the velocity in the headers is manitained by increased flow, but at low rpm the exhaust just sits in there.
Pretty much if your motor is stock, don't go too much above factory. On a stock 300 dual 2's or 2.25's would be all the more the motor could use, anything above that just makes it louder and starts to hurt your down low power.
Justin
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jordan150
Ford Inline Six, 200, 250, 4.9L / 300
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02-24-2007 06:18 PM