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11-15-2012, 10:33 PM | #1 |
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Need Help: Mid Pipe vs Down Pipe for N55
Hi guys. I got really confuse with the terms down pipe and mid pipe. I know its position is different, but which one do you recommend for better performance and sound? How does it affects the car? I plan to do just axle back but you guys make me think over and over whether to do mods with my DP and MP as well.
Just for your information, I got my car from out of state and here in California I have to smog it every two years, so I just want to make sure that those two are problems free with smog test. If it causing any problem, please let me know. Appreciate any comments and opinions guys. Please also mention what brand and why do you recommend it. Videos and sound files might help as well. Many people say Berk mid is the best but I'm open to other brand or manufacturer since I'm new for DP and MP. Thank you guys. Really need your help!
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11-15-2012, 10:41 PM | #2 |
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no doubt majority of restriction is in the downpipes, they contain the first set of catalytic converters. switching DPs will give you the largest increase in power
switching midpipes is primarily for sound improvements, power increase is negligible. however i wouldn't underestimate the increase in driving pleasure from better sound though. switching out downpipes will make your car NOT california smog legal, i'm not sure about midpipes, perhaps someone else can chime in
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MHD tuned Last edited by dbchun; 11-15-2012 at 10:47 PM.. |
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11-15-2012, 10:45 PM | #3 |
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As far as I know, downpipes will net you more of a gain than the midpipes.
On your model, being an N55, you only have catalytic converters on the downpipes. A lot of the N54 guys buy N55 midpipes to remove our cats as we have cats on both the DPs and MPs. Remove the cats on the downpipes or getting them swapped for high flow race cats and increasing the diameter or the pipes will improve the flow of exhaust and will also increase the sound of the turbo however if you need to smog your car every 2 years I think you're SOL unfortunately. You will not pass emissions tests with your cats removed or modified. In regards to the mids, I think that seeing as you don't have cats on the mids anyway you won't see a significant gain in performance by changing them to aftermarket pipes. With removal or changing to the resonators with aftermarket midpipes you will change the sound of the exhaust but it shouldn't affect emissions. Hope that helps. Good luck!
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11-15-2012, 11:22 PM | #5 |
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Actually I'm considering DP or MP because some people said doing only axle back will not give significant changes in the sound itself and that's why I'm asking here. So, in other words by changing my DP, I will fail the smog test? How about Mid Pipe? I just want to make sure that I'm not wasting my money for an axle back if in fact by changing my mid or down and using stock axle back will create better sound.
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11-15-2012, 11:25 PM | #6 | |
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You will be able to change your midpipe to whatever you want as in your model of car, they make no difference at all to the emissions. In regards to the sound, you will get the most change to the sound by changing the axleback due to the muffler. The second most change comes from the midpipes due to the resonators. The least will come from the downpipes but in your case there's not much you can do to change those unless you want to go through the hassle of swapping your stocks back in every 2 years.
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11-15-2012, 11:30 PM | #7 | |
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11-15-2012, 11:36 PM | #8 |
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Unfortunately I don't have any direct experience with exhaust modifications as I haven't done any on my car just yet. All that I know I've gotten from research on this forum and others.
Best bet would be to check out youtube for videos of different midpipes but I'm hesitant to say how much difference it would make on your N55. Most people who change their midpipes are those with the N54 engine. I would recommend just changing the axleback first and see whether you like it or not. That'll definitely make the most difference. If you're still looking for more then you could look at trying to change the midpipes.
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11-16-2012, 12:06 PM | #9 | |
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I can tell you that the downpipes make the biggest performance difference, you will actually feel the difference the first time you start the car and blip the throttle, just how much better it breathes without those catalytic converters on there. Then again, I wouldn't want to have to do that swap-work every 2 years...
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11-16-2012, 03:34 PM | #10 | ||
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11-16-2012, 04:26 PM | #11 | |
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BMW 135i QuickPower™ http://www.cp-e.com/products/bmw-1m/...power%E2%84%A2
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11-20-2012, 12:27 AM | #12 | |
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I'm not an expert. But if you change the DP you might have a yellow engine light. you might have to go with some tune to delete that yellow light. |
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11-20-2012, 12:14 PM | #13 | |
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BMS CAN Tool http://www.**********s.com/BMS-CAN-T...-Z4-35i-X6.htm
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