Greetings guys. So i had my car tuned and to get max power at the time of the tune it had a straight pipe, so no cat. When it was dun we pulled it off the dyno and at idle it spits out solid carbon particles. Nothing major just if you hold your hand there you can see specks. Now at the time the tuner said no big and im not worried about it but im looking for an explanation of why. Correct me if i am wrong, but at a stoichiometric rate there should be only co2 and h2o..correct? So if its running at its best potential, why would it spit carbon??? (running a little rich i assume..is that normal?).

 

Maybe because you have a test pipe on?

 

A relative of mine has a 1978 Lil' Red Express(the pickup with the semi stacks), and every time he would punch it, he would get little black specks on the quarter panels and bed cover. We figured it out to be the water in the exhaust(which is present under normal/stoich combustion) was dragging carbon from the exhaust piping out the end and getting it everywhere. I think thats whats happening to you too. And under perfect combustion there should only be CO2 and H2O, yes. But as we all know, cars are never perfect. Thats why when you take a car out and pound on it, it's called blowing the carbon out .

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by supereg2 &raquo;</TD></TR><TR><TD CLASS="quote">Maybe because you have a test pipe on? </TD></TR></TABLE>
Haha, fail.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by King V &raquo;</TD></TR><TR><TD CLASS="quote">A relative of mine has a 1978 Lil' Red Express(the pickup with the semi stacks), and every time he would punch it, he would get little black specks on the quarter panels and bed cover. We figured it out to be the water in the exhaust(which is present under normal/stoich combustion) was dragging carbon from the exhaust piping out the end and getting it everywhere. I think thats whats happening to you too. And under perfect combustion there should only be CO2 and H2O, yes. But as we all know, cars are never perfect. Thats why when you take a car out and pound on it, it's called blowing the carbon out .</TD></TR></TABLE>

I guess that probably it. It must just not be perfect all the time and creates carbon which eventually gets blown out. I was just kinda thinking about it and realized there should really not be any pure carbon....but thanks for the explanation

 

Or you could argue it depends on how "fast" the ECU's fuel tables ramp up. If they're increasing faster than the engine can keep up so to speak, you could get some excess carbon from the engine. I wouldn't worry about it too much as long as you don't start spewing black smoke like a diesel.