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straight pipes

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Would a straight pipe give the most power to a four stroke.......if the noise was bearable :cry:

SO would the loudest pipe give the most peak Hp?

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Engines require a certain amount of backpressure to run properly.

A straight pipe that is very large will give you awesome top end and absolutely obliterate low end torque.

A straight pipe that is very small in diameter would choke out the top end, but pull like heck off the line.

Adding an expansion chamber/muffler and using a pipe somewhere in between will give you the best compromise and keep sound levels tolerable.

Everything is a tradeoff. WHERE do you want the engine to perform best? High RPM or bottom end?

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Top fuel dragsters run straight pipes. I'm sure you lose a lot of driveability with no back pressure to speak of, but if you just want peak power....

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Top fuel dragsters aren't naturally aspirated, though.

Straight pipe your bike and you can expect to burn out your exhaust valves and ear drums. :cry:

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I read once that burned says "backpreassure" is a myth and it isn't needed for the engine to run :cry:

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What Wheelsup said..

Engine need a certain amount of back pressure to run good..

Running staight pipes would kill your bottom end throttle response,not to mention what it would do to your ears :cry:

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Drag racers run open headers and run fine.

Its all in the design of the exhaust system.

Thats why any multi cylinder exhaust system has a collector unless it uses a supercharger.

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Drag racers run open headers and run fine.

They also don't care about low RPM. They launch at 3000+... higher still for top fuelers.

It doesn't take much pipe to hold enough heat to protect the valves. Straight pipes on a bike, at least one running from the head to where the stock exhaust exit is, won't hurt the engine.

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Dont see many harley/coppers with anything but straight pipes.......... but I guess they look for sound more than power delivery.

Back pressure on a 2 stroke .......yes

four stroke ........why........... I have a hard time understanding why ( not questioning, just thinking)

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