See black residue inside the tip of my catback exhaust?
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Joined: May 2002
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From: Cloverdale Bc
See black residue inside the tip of my catback exhaust?
Guys I was wondering what this black stuff inside the tip of my catback exhaust is, I just drove it this morning so this stuff is pretty fresh, is this unburnt fuel or something else? what does unburnt fuel look like? It cant be oil, for I have just gotten rebuilt turbos last week!!!!!! any body??????
Super Snuggles
Joined: Feb 2001
Posts: 10,091
Likes: 34
From: Redmond, WA
Probably unburnt fuel, more commonly known as "smoot", and perfectly normal. It'll leave a film on the back of your car if you run without a catalytic converter.
BTW, you might work on being more patient. Eight whole minutes before you bumped your post to the top is NOT being patient...
BTW, you might work on being more patient. Eight whole minutes before you bumped your post to the top is NOT being patient...
I'm a CF and poop smith
Joined: Aug 2001
Posts: 3,957
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From: Hawaii
hold on, you are telling me it can't be oil, you better think again, rotaries burn oil by nature (via the oil metering pump as well as if you premix), also, rotaries run super rich and I agree with jimlab, its probally just unburnt fuel. I would not really worry about this stuff, start to worry about when you engine or turbos start to sound funny or act weird.
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Super Snuggles
Joined: Feb 2001
Posts: 10,091
Likes: 34
From: Redmond, WA
Originally posted by Toadman
It's "soot", like ash.
It's "soot", like ash.
A long time ago on the RX-7 mailing list, someone got their tongue tied (but not as badly as AARotary) and called it "smoot". The name stuck, and now many people call the oily film on the back of the car and the black crud in the tail pipe "smoot".
Senior Member
Joined: Oct 2001
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From: NNJ
Originally posted by 93TTRX7
hehe mine has white smoot in the muffler/exhaust tip...looks nice...like someone put their thing in there and jizzed in i...=/
hehe mine has white smoot in the muffler/exhaust tip...looks nice...like someone put their thing in there and jizzed in i...=/
Hey Jim cldnt it be an indication of it running to rich also?
I know a bike friend of mine who is very well known for tuning carbs and his bike doesnt get that crap build up on his exhaust tip like ours does.....He says if its running perfectly it wont leave a spec.
Senior Member
Joined: Apr 2002
Posts: 267
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From: Iowa City, IA
His bikes aren't rotary engines, rotaries run richer and burn more oil by nature so there will be more residue in the exhaust... Otherwise, why would we have so many problems with clogged cats/precats? hehe.
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