Exhaust issue: only 3 of 4 pipes have exhaust output
09-19-2018, 04:13 PM
#1
Exhaust issue: only 3 of 4 pipes have exhaust output
I just recently purchased a 2008 c6 coupe, which had a BB Bi-modal fusion exhaust system on it and now have noticed that the third exhaust pipe (left to right) has no output, initially noticed because of the lack of dust and residue inside the exhaust tip. I checked the output when the valve is both open and closed and the outcome is the same (nothing). Does anyone have any idea what could be causing this issue and help me with a possible way to fix the situation before I take it to a mechanic and have them diagnose it? Any help is much appreciated !
Last edited by vfortino; 09-19-2018 at 04:13 PM.
09-19-2018, 05:51 PM
#2
Melting Slicks
I just recently purchased a 2008 c6 coupe, which had a BB Bi-modal fusion exhaust system on it and now have noticed that the third exhaust pipe (left to right) has no output, initially noticed because of the lack of dust and residue inside the exhaust tip. I checked the output when the valve is both open and closed and the outcome is the same (nothing). Does anyone have any idea what could be causing this issue and help me with a possible way to fix the situation before I take it to a mechanic and have them diagnose it? Any help is much appreciated !
if so, you should be able to look and see if the valve is opening. I believe that these are vacuum operated.
09-19-2018, 06:17 PM
#3
Race Director
Easy to check, the default state is open. So if the car is off, the valves are open. After starting, they should close.
09-20-2018, 07:05 AM
#4
Le Mans Master
OP says it doesn’t matter if valves are open or closed, no exhaust flow from the one outlet. I don’t know what would cause that.
09-20-2018, 08:38 AM
#5
Team Owner
Sounds like it is internal, perhaps a baffle has failed - call B&B and speak with them and see what they recommend 
And for some who don't seem to read the whole post, the OP said it is when the valve is OPEN or CLOSED
Thanks,Matt
And for some who don't seem to read the whole post, the OP said it is when the valve is OPEN or CLOSED
Thanks,Matt
09-20-2018, 09:09 AM
#6
Safety Car
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If you look at the diagram in post #4 here: https://www.corvetteforum.com/forums...ally-work.html, and if the BB system works like the NPP OEM version, then the 2 inner pipes are straight through when the valves are open. If no exhaust exits one of the pipes when the valve is open, there must be an obstruction before the butterfly valve. I have to ask, though. How do you know that there is no exhaust when the valve is open? Do you have something like a mild-to-wild switch, pull the fuse, or did someone stand behind and check while you revved the engine past 3500?
Last edited by FatsWaller; 09-20-2018 at 11:51 AM.
09-20-2018, 10:51 AM
#7
Burning Brakes
Take a measuring tape and push it in the exhaust and see how far you can go. The side with the valve is a straight through design, so you should be able to push your measuring tape quite far in before you get stopped. That way, you'll know if it's opened, or blocked.