Black Smoke.....power or waste?

There is a reason a diesel engine smokes............it the fuel and the way it burns

Diesel fuel is slow burning when compared to gasoline. Diesel fuel is in a liquid form when it enters the engine, gasoline is a vapor mixed with atoms of air to make an explosive combustion process when compared to diesel. The thermal energy of a gallon of a gasoline is roughly 125,000 BTU, while the thermal energy of a gallon of diesel fuel is 137,800 BTU's. The diesel fuel has more energy per gallon, but burns much slower. As you introduce more fuel into the engine, it gets harder to completely burn it and smoke is the by product


As you introduce more diesel fuel into the engine for higher Hp, the engine can't completely burn it in the same amount of piston dwell time at TDC. The only way an oil/fuel is burnt completely in large Hp engines is to slow the engine RPM down for more piston dwell time at TDC, Increase the engine stroke for more piston dwell time at TDC. The longer the piston stays at TDC the more time in mil seconds for the fuel to be completely burnt. The new engines in cargo ships are very large with a max engine RPM of 150 RPM, the piston stroke is measured in feet, not inches. This is how they have made them more efficient, the piston dwell time at TDC is very long compared to a truck engine this give the fuel oil time to burn completely with little or no smoke

My truck can turn daylight to dark with it's smoke output under acceleration. It does smoke less than alot of other trucks when it is on a dyno, because I don't believe in wasting extra fuel for a small power gain. As you try to increase Hp in a truck engine the more power you want, the harder it is to achieve. I find that it's very easy to add a certain amount of fuel for a 250 Hp gain, but to get the next 200 Hp gain takes twice as much fuel in the same engine. The efficiency is dropping as the Hp increases, regardless of how much air you introduce with a larger turbo. It's the nature of dealing with a slow burning fuel source for energy, to achieve the hp goal you want

The reason the older truck engines from the 70s to early 80s smoked so bad is the fuel systems were low pressure compared to what is being produced today for the same Hp output or higher. A new Cummins common rail ISX engine has very high fuel pressure compared to a Big Cam III 400. The reason the inline 6 cylinder engine took over from the V8's is the longer strokes made them more efficient for the same power output and were easier to meet emission standards with.

Smoke maybe an advertisement that you've played with the engine, but it sure makes it nice to drive. I have a friend that I've worked on his truck for, he just dynoed it at the PDI dyno contest and achieved 851 Hp to the tires with no smoke. This guys pulls a custom white sided dry van and has no signs of a excessive smoke from the stacks on his van and wants to keep it this way. That's 975 Hp at the flywheel, the truck is fun to drive

 

ive seen alot of these company trucks smoking. i doubt its caused by gettin turned up.

 

You would make a great shop teacher!!

 

Detroit's 6V92 was prone to crack the main bearing saddles, spinning a bearing, and destroying the engine. This was especially true in the aftercooled version that put out 335 HP. There simply not enough structual support in the block for the added power from the 6V53. Detroit may have did some improvements to the block in the later years, but I do know in the 70's and early 80's this was a common problem. There were several fleets here that ran these engines, plus I had one myself that spun a main bearing.

I will say this, in the 335 setting the engine was very powerful in the single axle truck I owned, idled and ran very smooth, and I got close to 7 mph with it without really trying for fuel mileage.

 

You're assuming that the people would want to learn something I have to teach.........my patience is zero for someone that is smart, but doesn't want to use their head for nothing more than a hat rack. Unfortunately I grew up in a time when you were taught to at least show respect and politeness to someone with authority..........I doubt I'd survive in a classroom with todays generation

 

Kurt, I know you hate me repeating this over and over and over again but I don't care about your feeling toward what I'm saying - what matters to me is to say it one more time.

Please, take yours most explanatory posts that are already written as a start. Then try put them together as a whole thing, than write more and more and please come up with the full blown book for owner-ops that want to learn. Then you go for that self-publishing websites and sell each one for $90 a piece with no investment except your time

 

Mr Haney ,

Our v8's are now more fuel efficient than our inline 6's, is this due to the fact the inlines have egr? Or is there another reason for it? Reports are putting the new r730 at 9-11mpg's (euro) and alot of inlines are struggling to break 8 mpg (euro) with maybe 250- 300 hp less, if so is there a by-pass for the egr without removing it altogether ? could the fact that the v8 is a 900hp engine de-tuned for truck use be why they are not smokey? Just interested to know

 

Back when Cummins had the VT903, it would get better fuel mileage that the inline NTC Cummins buy about 1-1.5 MPG, or more.

 

Was this truck seriously smoking the tires with a loaded trailer on??? OMG!!!