Ecoboost Stain - Exhaust???
04-25-2011, 10:19 PM
#12
So we all agree that it's exhaust. I put 200 miles on the truck before the 1000 miles I drove it to Jupiter, FL. No exhaust drooling anywhere in MD before the trip or in Jupiter for the week I was there. Is it the humidity from the rain in the colder temperatures in MD?
Different topic, but I towed a center console boat with T-Top and windshield (6500 lbs on trailer) from Jupiter to Fernandina Beach, FL with the 3.31 rear and got 9.8 MPG with a strong east wind. I was traveling north. It towed at 1600 RPM's at 65 MPH, and only downshifted climbing the overpasses.
After that, 18.2 MPG at 75 MPH for about 650 miles all highway. Four of us with a full bed of gear.
Maybe there's a small leak in the exhaust joints, but it doesn't make any noise, like a ticing header leak.
Different topic, but I towed a center console boat with T-Top and windshield (6500 lbs on trailer) from Jupiter to Fernandina Beach, FL with the 3.31 rear and got 9.8 MPG with a strong east wind. I was traveling north. It towed at 1600 RPM's at 65 MPH, and only downshifted climbing the overpasses.
After that, 18.2 MPG at 75 MPH for about 650 miles all highway. Four of us with a full bed of gear.
Maybe there's a small leak in the exhaust joints, but it doesn't make any noise, like a ticing header leak.
04-26-2011, 12:19 PM
#16
Having lived with direct injection gasoline engines for 3+ years and living on the Solstice forums, there was a lot of discussion about all the "soot" coming out of the motors when they first came out. After considerable discussion, a couple of GM engineers came over and said that the soot is normal for a direct injected engine.
Since they are all fly by wire, the computer can and does vairy the timing and duration of . . . just about everything . . including that of the injection of fuel directly into the cylinder. They can do things with the fuel that were impossible in the past. They can in fact do things like crank up the timing and compensate by slightly increasing the duration of fuel injection to counter knock. In the long run, they make more power / torque and overall save fuel. But under certain conditions the ECM controls temperature inside the cylinder and / or knock by dumping in a bit more fuel. Not all the fuel gets burned off by the time it hits the cat, where it gets burned and produces soot.
It is a by-product of the direct injection motor.
Since they are all fly by wire, the computer can and does vairy the timing and duration of . . . just about everything . . including that of the injection of fuel directly into the cylinder. They can do things with the fuel that were impossible in the past. They can in fact do things like crank up the timing and compensate by slightly increasing the duration of fuel injection to counter knock. In the long run, they make more power / torque and overall save fuel. But under certain conditions the ECM controls temperature inside the cylinder and / or knock by dumping in a bit more fuel. Not all the fuel gets burned off by the time it hits the cat, where it gets burned and produces soot.
It is a by-product of the direct injection motor.
04-26-2011, 02:07 PM
#18
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Flames out the tail pipe ? Now that would be COOL
port the exhaust out the rear, both sides. That would burn some brown noses on tail gaters 
Oh, and the soot, just Eco Poop. Rub its little nose in it and never happen again. No, wait, that works for puppies, Never Mind...
04-26-2011, 02:24 PM
#20
FX4 SCrew TT'd V6
Flames out the tail pipe ? Now that would be COOL
port the exhaust out the rear, both sides. That would burn some brown noses on tail gaters Oh, and the soot, just Eco Poop. Rub its little nose in it and never happen again. No, wait, that works for puppies, Never Mind...
I have these same marks in my driveway. The colder more humid weather will definitely increase this.......as I have seen in Mid MO.