Modded exhaust "thump" on high-RPM upshift: not complaining, just curious |
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10-08-2015, 12:45 AM | #1 |
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Modded exhaust "thump" on high-RPM upshift: not complaining, just curious
Since getting a Dinan Freeflow exhaust installed on my 228i 8AT I've noticed a pronounced "thump" (both a sound and a brief percussive sensation) from the underside of the car during high-RPM upshifts. FWIW, the new cat-back exhaust eliminates the factory computer-controlled exhaust valve, according to Dinan. I'm not complaining about this, just curious about what is happening here that didn't happen before and if it's to be expected. It seems completely harmless but if it isn't I would obviously be grateful to know. Finally, how would this sound be perceived from outside the car, if at all? Thanks!
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2015 BMW 228i M Sport w/Track Handling Package DAP | Lighting | Premium | Tech DINANTRONICS Performance Tuner Stage 1 | DINAN Shockware | DINAN Free Flow Exhaust | DINAN Performance Spring Set + Ride Quality and Handling Kit Last edited by BarryJI; 10-08-2015 at 01:31 AM.. |
10-08-2015, 04:37 AM | #2 |
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Does it sound like a Volkswagen DSG on the upshift?
If it's a burp when you are shifting at 4-7k rpm it is perfectly normal, in fact a lot of owners find this noise addictive such as myself |
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10-08-2015, 05:38 AM | #3 |
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A sound clip would be helpful...
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10-08-2015, 01:52 PM | #4 |
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I think it's this. It may well be an offshoot of the tune, not the exhaust. Either way, it appears not to be something to worry about. It certainly does not pause the upshift unduly.
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10-08-2015, 08:14 PM | #5 | |
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10-08-2015, 08:34 PM | #6 |
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Kind of. It's a kind of a thud. I don't know what it sounds like from the outside of the car. I will record it when I next have a passenger. To do so alone would not be safe as it happens only during aggressive shifting at between 4k and 7k rpm.
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10-13-2015, 07:20 PM | #7 |
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this kinda sound? i love it
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10-14-2015, 01:03 AM | #8 |
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Yeah, that may be how it sounds from the outside. I was mistaken to describe it as an exhaust-related sound (although I first heard it after getting a new exhaust). The "thump" may be from the transmission or the drivetrain for all I know. It's certainly an "I'm going fast" sound, it does not appear to slow down the 8AT's very fast upshifts, it occurs only when accelerating pretty aggressively and seems harmless.
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2015 BMW 228i M Sport w/Track Handling Package DAP | Lighting | Premium | Tech DINANTRONICS Performance Tuner Stage 1 | DINAN Shockware | DINAN Free Flow Exhaust | DINAN Performance Spring Set + Ride Quality and Handling Kit Last edited by BarryJI; 10-14-2015 at 10:59 AM.. |
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10-14-2015, 08:47 AM | #9 | |
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'14 220i M Sport | AW/CR | PUR Wheels RS07 19" | KW V1 | MTC Design F2X Kit [CF] | Stage 1 ECU Tune | Eventuri CF Intake | Manhart Race Exhaust/Resonator Delete | ER HFC Downpipe | F8X LCA + TS | M Style Grilles | Gloss Black Roof | Custom Steering Wheel | Autotecknic Competition Shift Paddles [YMB] Instagram: @icyj95 | FB |
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10-29-2015, 06:24 PM | #10 |
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Ive alway attributed at least some of the "percussive" aspect you're on about to the active sound too. The subwoofers are under the seats after all (with HK). However, i do experience more aggressive shifting from time to time with the 8AT in sport + that compounds the effect somewhat and I'm running the stock exhaust atm.
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10-30-2015, 02:30 PM | #11 | |
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