exhaust question

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Feb 19, 2009 | 01:16 PM

Adam0331

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From: Jonestown, PA

exhaust question

A buddy of mine just bought an 85 with the 6.9 and it has a 4" stack, and someone told him that 4" exhaust is too big. Is that right?

Feb 19, 2009 | 01:23 PM

84 f250 6.9

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whoever said that is smokin somethin funky cuz i have stock 2.5 exhaust runnin into a single stack out the bed which is 5.5 in diameter and my truck runs awesome after i did that so id say 4 inches is just fine

Feb 19, 2009 | 01:32 PM

Adam0331

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That's what I was thinking. Thanks.

Feb 19, 2009 | 01:58 PM

84 f250 6.9

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actually the bigger the exhaust the better straight pipe it if it isnt already cuz unlike a gasser backpressure hinders diesel performance .. even more so with a turbo

Feb 19, 2009 | 02:00 PM

Adam0331

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Yea I knew about the backpressure with a turbo, I just wasn't sure if the 6.9 was any different or whatever.

Feb 19, 2009 | 03:30 PM

ghunt

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Maybe if he had giant pipes coming directly off the manifold it'd be a problem...but, more than likely it's got mostly stock exhaust back to the stack, so I'm sure it's fine.

Feb 19, 2009 | 03:39 PM

fonefiddy

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From: Duluth, Mn.

Generally, bigger is better. But it gets to a point of diminishing returns at around 3" for NA, and 4" Turbocharged.

exhaust question

exhaust question

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