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Old 09-30-2009, 01:04 PM   #99 (permalink)
HP Logic
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Join Date: Mar 2009
Location: Wellington, FL
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Quote:
Originally Posted by kannibul View Post
You're right, I've not seen one.

I was just surprised that it happens like that - I mean, through a lot of RPM range, then all of a sudden two puffs of smoke...as if it's building up in the exhaust then gets blasted out....but I know that shouldn't be true.
...with F/I cars...typically they will run best/safest with an Air/fuel ratio of about 11.5 : 1...this is significantly richer than a naturally aspirated car which will like 12.5 : 1 or leaner....that being said...the unburnt portion of the combustion process can sometimes create black smoke...most cars with open wategates will expell the overly rich discharge through the wategate dumps before it can reach the tailpipes....but sometimes the wastegates will adjust momentarily to control boost and you get a diversion to the rear exhaust section......

...in short: The black smoke is normal...and depending on the cars plumbing/turbo setup you will see it intermitently....

-Jack
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