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      04-24-2013, 03:33 PM   #1370
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Drives: E92 335xi 6 speed
Join Date: May 2010
Location: Slc, ut

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2008 BMW 335xi  [5.00]
Originally Posted by nsquared View Post
Can anyone explain to me in simple terms why a 3 inch dp will be better than 4 inch dp for my N55?
as far as I know, I would assume you would want a 4 inch if you could make it fit, just cause the point of having DP's in the first place is to eliminate some of the resistance that the turbo deals with... BUT I dont know if the whole backpressure thing comes into play with DP's. its kinda like the idea of you dont really want to hack off your whole exhaust cause it'll cause problems... Maybe see if you can find what amount of back pressure the N55 needs... then go from there