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-   -   Ecomod gasoline generator (https://ecomodder.com/forum/showthread.php/ecomod-gasoline-generator-28080.html)

oil pan 4 01-29-2014 01:33 AM

Ecomod gasoline generator
 
I got my $50 CL generator up and running really good. Its an old coleman 1875 watt generator on an old horizontal briggs 5hp.
I need 2 settings, a fuel saver mode and a power mode.
The power mode runs a cold air intake, and sets the generator to 63Hz and runs up to 125v. The power mode runs air compressors or welders.
The fuel saver setting I turn the generator down to about 50Hz which produces a little over 100v that can be boosted up to 120v with a varrac, that will run most gadgets that put a light load on the machine, charge power inverter batteries, stuff like that.
I think a warm air intake might help some. The generator will be out side and I will most likely need to run economy mode in winter during unexpected power outages.
EGR will be useless with out a way to advance the timing.
Then in power mode when I have to fire up the welder.

I also want to add a nice up sweeping straight pipe exhaust that I can add a muffler to. The straight up exhaust will blow poisonous CO up and away from people and the house. I need to figure out the best length to make the pipe. 2 or 3 feet will be no problem. More of a safety and power mod, not so much an economy mod.

Cobb 01-29-2014 06:58 AM

Huh?

Most eco minded generators use a dc to ac converter and an electronically controlled throttle that ramps the engine rpms up and down as needed depending on the load. Since the output is done electronically the hz is the same regardles of rpms. Think of it as the gas motor is driving an alternator and that is powering an inverter.

The engine mods do the same across the board. Most small engines the exhaust is the most restrictive part because of the spark arrestor, noise damepning. The timing can be advanced by use of different keyways and some ignitions have some wiggle room to rotate the housing some as well as positioning of the magnetio to the flywheel.

You can also shave the block and or cylinder head to up the cr.

Daox 01-29-2014 12:13 PM

Interesting project. How do you plan on monitoring fuel efficiency and if your mods are doing any good?

oil pan 4 01-29-2014 12:19 PM

To monitor fe I will use a kill-a-watt meter, timer and filling the gas tank all the way up.

Daox 01-29-2014 12:20 PM

Do you have outtages that often? Gas would go bad long before I needed to use it here.

P-hack 01-29-2014 12:58 PM

I guess that is a fair point, I mean if the most you save is a couple gallons/year then how much tinkering is that worth? You might want to measure current gph at high load and again at low load for starters and see what the potential return is (with a small graduated tank presumably). You need some benchmarks. Serious gains might be rather involved (i.e. fuel injection, electronic ignition, custom ECU (arduino can handle it), egr and throttle solenoids, etc).

oil pan 4 01-29-2014 01:06 PM

The main use will be powering the welder or air compressor in remote areas.
Plan is to normally keep it set up for high power use.

To keep the gas from going bad I use ethanol free gas with a little bit of 2 stroke oil.
For most outages I hope to just use power inverters. Only going to fire up the generator to cool down deep freezer and fridge and recharge inverter battery packs.

P-hack 01-29-2014 01:14 PM

I picked up a small 3hp generator at a garage sale for $35. If this 5hp is your bread and butter, you might want to leave it be (and be able to run the fridge while you are on the job leaving the 3hp @ home), might even get the smaller one to run on natural gas.

arcosine 01-29-2014 01:46 PM

You could lean out the mixture screw for eco mode, make the spark gap bigger, and put on a hot air intake. As long as it doesn't bog. Not much you can do with timing except make the point gap wider. Maybe thinner weight synthetic oil.

oil pan 4 01-29-2014 02:50 PM

The carb has fixed jets, there is an idle mixture screw. But since it idles at 3600rpm I dont think it will have much effect.
I will widen the spark gap, good idea. I forgot about that.

I will pick up bigger a diesel generator at some point. I have a requirement for 220v power that isnt currenty being met by my little 5hp gasoline unit.
Next one will have to put out at least 6kw.

P-hack 01-29-2014 03:29 PM

you can always add a "calibrated" induction leak, tapped into the exhaust maybe.

oil pan 4 03-31-2014 10:51 AM

I have since picked up a broken 7kw generator, and fixed it and re wired it.
Its got electric start, the riding lawnmower sized battery was dead, I had an optima battery collecting dust so I put that on there along with a pure sine wave 1000w inverter.
I think with a 1000w inverter on the generator, a 350w and 750w inverters on my LiFePO4 starting packs I should be good for powering small items efficiently.

The small coleman will be sold at some point since it cant power my smaller welding machines very well.

This large generator should be able to electrically power my plasma cutter with ease. That plus a gasoline air compressor and I can go off grid with my miller specrtum 625 plasma (a decent plasma that can cut 3/4 inchs of steel and clean cut 3/8 inch aluminum or stainless).

oil pan 4 04-01-2014 09:23 PM

The new generator can run my plasma cutter at nearly full power.

Cobb 04-03-2014 08:47 PM

So, how did you "eco" mod it? Just adjust the plug gap and added a cai?

Sounds like you may of raised or lowered the governed engine speed to raise and lower the volts.

Lastly, it sounds like the inverter is connected to the starter motor battery? Or is it connected to a battery and to the 12 volt charger circuit of the generator?

Any test results on actual fuel consumption, fuel to kw?

Just wondering as Ive used a small 800 watt one from harbor freight at half load. 4.5 hours. With old gas it runs about 3 hours. :eek:Unlike my stihl chainsaw, it seems to run on anything. The chain saw refuses to start unless its fresh gas.

The chain saw you ask? Its stock, works on 6-7 medium size trees before it needs a refill. I run it full throttle once the chain gets within half an inch of wood. :thumbup:

oil pan 4 04-04-2014 12:52 AM

The big generator is just going to run 3600rpm, the inverter will run off the starting battery and I will keep the 12 volt battery charger handy.
I have not tested fuel consumption.

Cobb 04-04-2014 08:16 PM

At the machine shop they use to get custom ground cams, use a piece of Plexiglas and emery cloth to mill the head on the old brigss n straton engines to make more power.Of course they were out for power, not saving gas. I guess you can mod a smaller engine for more power like a 3 hp in place of a 5 and mod it for more power and that will save?

oil pan 4 04-05-2014 01:28 AM

Actually more "power" from the engine would be a good thing.
The 7kw generator is rated to put out 29 amps at 240 volts. Problem is the plasma cutter uses 30 to 31 amps. The electrical portion can take that kind of power out put, but the engine rpms drop off, cant keep up.
I need to check apparent power on my plasma.
Yeah I can run it fine by turning it down a little, but who wants to do that.

Running a smaller engine harder does save gas.
My air compressor uses a real old 5 horsepower flat head briggs, if I bump compression it would make more power, with more power I could stick a larger pully on the engine and get more air out of the compressor. Maybe run 1 compressor instead of 2.

The 7kw generator has a new style Briggs and Stratton with an OHV engine. Bumping compresion isnt as easy.
The 1900w generator has a slightly newer version of the engine on my air compressors engine, the generator is rated for 18 or 19 amps but will hold a 22amp load no problem. So its good.

I am running into a basic fundamental problem where the rate of work I can do is limited by the horsepower output of my machines.

Cobb 04-05-2014 05:25 PM

Maybe a stupid question, but is it more economical or just convent to use a generator vs shore power?

Ive considered buying a generator to try my hand at welding and a contractor said our home was too old for a load like that and suggested calling the power company to get a new meter/service installed. Power company said they can give me up to a 440, but it will have a monthly fee rather I use it or not.

I kind of concluded I would buy a generator that doubles as a welder to try it. That way I got a generator too for power failures or maybe I can get 90% of my money back reselling it?

My smaller 400-800 watt generator was to run my fathers oxygen machine. We use it since he passed away for power failures and I use it to run electric yard tools vs plugging in multiple extension cords or buying one long extension cord.

oil pan 4 04-05-2014 06:15 PM

You dont need 440v power to run a home hobbyists welding machine.
Only really powerful machines can run 440.
If you can use an electric clothes dryer or electric cooking range you have more than enough power capacity to run any normal welding machine.
Welding generators are very expensive since they have both high voltage and low voltage arc welding windings. But 120 and 240 standard generators make poor power supplies for welding machines unless they are grossly over sized. A 2000 watt generator wont power welding machine that needs 2000 watts, not even close, I already tried it.

I have a sorry old 100 amp power service connection and use a fairly good size 230 amp arc welder no problem.

I have made very long, very heavy power cords for both standard 120 volt and 240/120volt power to avoid running the generator, because gas is expensive.

Cobb 04-16-2014 05:22 PM

Have you tried a new or heavier power cord? I use to use a generic orange electric cable to plug in my phev kit and it would take 4-5 hours to charge up. I use to plug it into a power strip by itself for extra safety.

Well, it tripped the braker on the strip and I went and purchased a 10 gauge extension cord. I found I cut my charging time in half. I also did a similar experiment with my 13 amp leaf vac. The lights blinked when I turned on the vac with a regular cord, with the 10 gauge it didnt. The vac held its speed better and didnt get as bogged down under load either.

oil pan 4 04-16-2014 11:20 PM

My heaviest power cord has 6ga lines, 10ga neutral.
The longest one uses 8ga lines and 10ga neutral.
Then I have 10ga 120 and 240 volt cords.
I also have the usual 14 and 12 gauge cords.


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