Andertusa
Full Access Member
Does anyone have usable data on the powerband figures of these engines? Like they make x 2 idle, x 2 1200 etc? Also, what is a steady-rate fuel consumption at a given RPM?
Powerband and fuel consumption figures?
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Andertusa
Full Access Member
Nobody knows of any info regarding what these engines do in steady-state running? I'm interested in building a homemade alt-fuel generator and the fact that these engines can eat WVO, WMO, Bio and reg diesel makes this thing a natural for my application.
Andertusa
Full Access Member
I was wondering specifically how much power they make at idle, as it would be spinning a generator-head that needs a SPECIFIC amount of power to drive, and for longevity, I'd prefer to run it steady-state at idle, so, I NEED the idle power and while it's at idle, how much does it drink, because that will determine the size of the fuel tank this mobile genny-set gets.
jwalterus
Made in America
Idle fuel consumption IIRC is something like 1/2 gal per hour
Oiling sucks at idle, figure on using it at high idle if constant, about 1k rpm
this is NOT a stock truck:
Sanitized some because it's a member's truck
Oiling sucks at idle, figure on using it at high idle if constant, about 1k rpm
this is NOT a stock truck:
You must be registered for see images attach
Sanitized some because it's a member's truck
Somewhat irrelevant but my 460 truck burns about 6 GPH pulling my boat (guesstimating around 5000 lbs total?) at 70 MPH, 3.55:1 gears and 2000 RPM. My boat, a 23' inboard ski boat with 454, direct drive 1:1 trans and 13x12 3 blade burns about 6 GPH at 22 MPH and 2500 RPM pulling my 200 lbs self. Thought it was interesting they both had the same fuel consumption when working for intended purpose.
My IDI? 11.87 MPG average over past 3 years with a best of 15.22. Not sure on GPH at any particular load.
My IDI? 11.87 MPG average over past 3 years with a best of 15.22. Not sure on GPH at any particular load.
fsmyth
Full Access Member
I use this:
If you need to get more accurate, you must know the efficiency of the engine,
the average load, and the fuel quality. But it's close enough in most cases.
You must be registered for see images attach
If you need to get more accurate, you must know the efficiency of the engine,
the average load, and the fuel quality. But it's close enough in most cases.
mblaney
Full Access Member
I think fuel consumption is more dependent upon load, not rpm. An engine at idle (no throttle) will drink less than at the same rpm but with half throttle.
Maybe look at this from the other end - what are your load requirements (from the genny)? It might be easier to work backwards with some estimates of efficiency to determine what size engine you need. If you are hoping to idle a 7.3 forever and have it spinning out 4 amps at 110V then that would be the least efficient way to do it.
edit: fsmyth, I just opened your chart
Maybe look at this from the other end - what are your load requirements (from the genny)? It might be easier to work backwards with some estimates of efficiency to determine what size engine you need. If you are hoping to idle a 7.3 forever and have it spinning out 4 amps at 110V then that would be the least efficient way to do it.
edit: fsmyth, I just opened your chart
G. Mann
Full Access Member
Your generator needs to spin at 1,800 RPM exactly to make 60 cycle, 120 or 240 power, or 3 phase, either one.
Most generators are direct drive right off the crank.. some are belt or gear drive for slow speed engines, but the generator still has to spin at 1,800 RPM ... of 3,600 RPM, depending on how many poles the generator has.
I can't think of a generator big enough to set behind a 6.9 or 7.3 that doesn't spec out to the 1,800 RPM number to make electricity.
If speed droops, cycles droop, and voltage droops.. then things don't work well and smoke escapes from the electrical device.. same for to much speed... in reverse. Instead of 120 volts.. you may be making 150... more smoke..
Most generators are direct drive right off the crank.. some are belt or gear drive for slow speed engines, but the generator still has to spin at 1,800 RPM ... of 3,600 RPM, depending on how many poles the generator has.
I can't think of a generator big enough to set behind a 6.9 or 7.3 that doesn't spec out to the 1,800 RPM number to make electricity.
If speed droops, cycles droop, and voltage droops.. then things don't work well and smoke escapes from the electrical device.. same for to much speed... in reverse. Instead of 120 volts.. you may be making 150... more smoke..
fsmyth
Full Access Member
Not necessarily. Depending on the number of poles in the 60 cycle generator head,
the speed could be any multiple of 600: 600, 1200, 1800, 2400, 3000, or 3600.
1200 is common on larger generators, 3600 on very small ones.
And in a generator/inverter combination, the speed could be anywhere from DC to 4500.
from a towtruck mechanic standpoint, you do not want to run any motor at idle only for hours. the oiling system is not designed to do support that and the rings will wash down from it being too cold. max ideal efficiency for the IDI is 1100 to 1500 rpm when running PTO loads. over 1000 rpm, the rings are efficiently sealing, the oil pressure is at 50-70 psi and there is enough heat generated to keep everything in the generator shack warm and happy. I found a family of raccoons in a gen shack once, and I don't know who was more startled. I managed to shoot two of them, but they got back at me by ******** everywhere in the shack. :O
Andertusa
Full Access Member
I'm looking at modifying a generator head(48-horse 24,000 watt) intended to be driven by the 540RPM-PTO of a tractor.
Andertusa
Full Access Member
In truth, 100RPM wouldn't be that bad, I'm just looking at running it low and slow for potentially LONG times, I just don't like the idea of needing to keep an engine at 3600 for hours.
Torque peak is low on these engines. And to power a 24kw generator, they'll hardly be working. As far as efficiency: being in the 'powerband' will be where the best power to fuel consumption ratio will be. My truck, for example, starts picking up at 1800 RPM, and the sweet spot is 2000-2200 RPM.. I have a non wastegated turbo, so that's probably why that's when I start to really feel it. If I'm towing and drop below 1800 RPM, there's no recovering from it unless I downshift to get back on the powerband. Another observation is that I barely have to be on the throttle to keep the speed steady if I keep the RPM in the sweet spot.
For your application, throw a small turbo on it. Since it won't be used for high load, it won't need a ton of flow, and will spool at low revs. It'll help with efficiency furthermore.
For your application, throw a small turbo on it. Since it won't be used for high load, it won't need a ton of flow, and will spool at low revs. It'll help with efficiency furthermore.
