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      01-21-2006, 08:17 PM   #1
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Thumbs up backpressure good or bad?

Hi guys, I have always thought about removing a resonator from my E90 to produce a more throaty sound. However, i've heard a lot of ppl said that if i remove the resonator i'm going to lose backpressure and also lose power. but recently i researched online and i found an explanation from http://auto.howstuffworks.com/muffler5.htm
a fairly reputable website and it actually says more backpressure = less power ("mufflers like those in the previous section produce a fairly high backpressure. This subtracts a little from the power of the engine")... so now i'm wondering if losing back pressure really gonna make the car lose power or gain power?? is there anyone on the board who has conducted a resonator removal already? is there a difference in sound/power? thanks a lot guys!
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      01-21-2006, 10:22 PM   #2
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I have had my resonator deleted and I was pretty happy with the results there is a link to a sound clip in my sig... I didn't notice a difference in power at all and I really wouldnt worry about it if I were you...
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      01-22-2006, 03:32 AM   #3
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Its actually not a good idea to just remove the resonator if you arent pushing more air through the car. The car is currently tuned for as close to perfection as possible by the BMW engineers. You need some back pressure when your exhuast and intake valves are open to keep the cylinder temps hot so that they dont cool down and slow down air movement through the cylinder. If you arent pushing more air through than before, having a less constricted exit on the exhuast doesnt help. It actually creates turbulance, usually found in the exhuast manifold that hinders the flow and as a result creates more back pressure than with the resonator.

But I think in both situations, it wouldn't be noticed on the butt dyno.
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      01-23-2006, 05:05 PM   #4
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poldim wrote in part, "Its actually not a good idea to just remove the resonator if you arent pushing more air through the car. The car is currently tuned for as close to perfection as possible by the BMW engineers. "
Poldim is absolutely correct.
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