02-03-2022, 01:24 PM | #1 |
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435i OEM Valve Muffler Bypass
I wanted an exhaust solution that was quiet most of the time but has the flexibility to be loud when you want to have some fun. This is the little project I came up with that L&G Auto(Markham, ON) completed for me. Of course, video doesn't accurately represent actual sound but it will give you a good idea. I had 2 main concerns with this project; first that the OEM exhaust valve would rattle from the increase pressure. It did not! Second, I was worried it would sound loud and crappy with the straight pipe, but it doesn't! In fact, it sounds quite different then a straight up muffler delete in terms of tone. Since with the valve open, some of the gas is still making it to the muffler, it "cleans up" the tone significantly. In other words, you get the increased volume without a raspy/crappy tone. Overall, I am very happy with this modification since it retains OEM valve & control and gives the car 2 personalities.
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02-04-2022, 12:15 AM | #4 |
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I thought about doing something similar for a long time but retaining the stock side with the flap from the muffler and essentially adding a "bypass" pipe from pre-muffler to right before the flap. The geometry just isnt very good with where the flap is
Last edited by thejeremyman9; 02-04-2022 at 02:13 PM.. |
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02-05-2022, 07:16 PM | #5 | |
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I went down a bore size so I could run two pipes pre-resonator, that allows me to have a bypass valve pre-res and it ports straight into the tail pipes.. I haven't had any clearance issues and I'm on coilovers. On another note you can now pick up the oem style valves via aliexpress - they are wirelessly controlled by fob but utilise the same sping style valve, they are much better than the motor/butterfly style ones that you can pick up for £30-40.. man those things rattle after a few thousand miles and are slow at operating.
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2015 435i - 401whp
Scorpion catless dp, VRSF 6.5" HD FMIC, MST V2 inlet, NGK 97506, MHD Stage 2+ 102, xHP Stage 3, M Performance Exhaust (modified for valved straight thru) |
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05-25-2024, 06:39 AM | #6 | |
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