02-12-2020, 04:23 PM | #1 |
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Cold Start Exhaust Sound
I've noticed that my exhaust sounds deeper/louder at the end of the cold start cycle (after the revs drop to normal idle) for a short period of time, maybe 10-20 seconds. Then I hear a noise, possibly a valve or actuator, then the exhaust sounds quieter/normal. I originally thought this was the exhaust valves closing, but after watching the valves I confirmed they remained opened the entire time. Stock tune.
Has anyone else experienced this? Or is anyone able to explain what is happening during the cold start process that causes this difference in the exhaust sound? Thanks. |
02-13-2020, 02:21 PM | #2 |
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i dont have an explanation of he cold start deeper/louder tones, but i removed my exhaust valve connections. this seems to keep the values open all the time giving it that deeper/louder tone all the time
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02-13-2020, 02:59 PM | #3 | |
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MikeM6148.00 |
02-13-2020, 10:43 PM | #4 |
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The computer retards the timing in order to heat up the cats. Retarded timing equals higher exhaust temperatures.
When running modified exhaust and downpipes, it is annoyingly loud. It can be tuned out. My Z06, with headers etc. would wake the dead on a cold start.
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02-14-2020, 05:15 PM | #5 | |
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02-15-2020, 09:05 AM | #6 |
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I play with exhaust quite a bit. My favorite, so far has been downpipes and stock mufflers with an X Pipe. The X Pipe changed it dramatically.
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pennsiveguy3552.00 |
02-15-2020, 03:00 PM | #7 | |
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Which downpipes and x-pipe are you using? How is the gas smell with the downpipes? Thanks. |
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02-16-2020, 06:12 AM | #8 |
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I’d also like to know if the x pipe took out the raspiness. The stock exhaust with catless downpipes has too much rasp for me.
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02-23-2020, 07:45 PM | #9 | |
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It's not bad but I feel a little guilty. I'm going to weld in a set of ceramic matrix cats and see how that works. It's hard to quantify or describe the sound. It got rid of a lot of raspiness and smoothed it out. It made it quieter that I thought it would. I think it's just about right. I thought it was too loud without the X Pipe.
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F85MTuNED1620.50 |
02-24-2020, 01:48 AM | #10 |
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Guys, got the perfect exhaust sound.
I didn’t want to install sports catalysts initially, since in any case they reduce the exhaust gas throughput and also tend to be destroyed, although they are much more durable stock catalysts. Installed downpipes and trompe lambda probes, so as not to open the computer, while maintaining a guarantee on the engine and transmission. The exhaust sound turned out to be almost comfortable in volume and an unpleasant 'grunt' appeared)) I was advised to install two resonators immediately after the standard resonators. Resonators ordered. Material - stainless steel, quality of work - high. The resonator has an inner diameter similar to the diameter of the exhaust pipe. Installed resonators, received a noble and wonderful M-th exhaust sound. Happy as an elephant and as happy as possible)) |
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