Back pressure - Ford Powerstroke Diesel Forum
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post #1 of 4 Old 10-20-2011, 08:51 AM Thread Starter
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Back pressure

I cut off my muffler and noticed when I start the truck it revs the engine for a second then back to idle but I hear a slight knock. Im just wondering if my 2002back f350 7.3 needs the back pressure from a muffler or not. Cause I was thinking of welding. Straight pipe off the down pipe.
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post #2 of 4 Old 10-20-2011, 09:19 AM
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Back pressure is the enemy of a turbo.

A gas engine needs backpressure to run efficiently. Not so with a turbo diesel.

I'm lost as to why your engine would rev up now. Hopefully others have an idea


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post #3 of 4 Old 10-20-2011, 05:47 PM
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Your turbo is your motors back presure. The turbo doesnt like backpresure.

So, I have a feeling you are hearing the motor start and rumble before the turbo starts spinning at speed.

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post #4 of 4 Old 10-20-2011, 05:53 PM
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Could just be a little injector noise. These engines can have noisy injectors at times.
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