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Old 12-03-2006, 10:15 PM   #1
T3rminator
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Default Exhaust sounds louder on cold start ups...why?

I've always wanted to know why the exhaust sounds louder when you start the car in the morning. For example, when I start my BA XR8 in the morning you can hear it thump on idle like a V8 should. But drive it for 5 minutes when it reaches operating temp and it idles soft. Any explanations as to why this occurs??

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Old 12-03-2006, 10:15 PM   #2
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Change in idle rpm??
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Old 12-03-2006, 10:22 PM   #3
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The engine isn't combusting fuel at peak efficiency so alot of unburnt fuel gets burnt off in headers.
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Old 12-03-2006, 10:33 PM   #4
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Quote:
Originally Posted by xd5.8l
The engine isn't combusting fuel at peak efficiency so alot of unburnt fuel gets burnt off in headers.
Bingo ..........
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Old 12-03-2006, 10:49 PM   #5
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Quote:
Originally Posted by svo347
Bingo ..........

What? Playing "BINGO" changes how loud my exhaust is ??? WOW. :nutsycuck
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Old 12-03-2006, 11:18 PM   #6
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Quote:
Originally Posted by svo347
Bingo ..........
You sunk my battle ship


hehe sorry, you had to watch The Simpsons tonight ;)
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Old 13-03-2006, 08:20 AM   #7
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Its called auto choke in the pcm richening up the mixtures till it starts to warm up, let it sit idle for a few minutes and listen to the idle taper off when warming. Rember the old days with carby pull the choke out nice lumpy idle.
But yes they do sound good when cold quiet a solid idle.
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