Charcoal gasifier questions

So I’ve been lurking on here for a while now trying to decide what I would like to build, and I think I’ve finally settled on charcoal. A few questions though to the people on here that really know the charcoal systems well.

First, does charcoal gas need to be cooled the same as wood gas does? Is there an ideal gas temperature to try and achieve before entering the engine?

Second, I’ve seen many different systems for wood gasifiers (FEMA, WK, Imbert), but haven’t seen any specific charcoal units (other than Gary’s simple fire). Is charcoal more forgiving and less finicky that we don’t necessarily need very specific proportions? Or are there a pile of threads that I have missed?

Third, and this relates to the second, what is the generic system of choice for most of you charcoal heads? Downdraft? Updraft?

Thanks for any replies! Sorry if a lot of these questions may have been answered before, I’ve tried searching the threads however some of them are 100s of replies long and sometimes stray off topic from the original question so it’s hard to find the specific info you’re looking for sometimes.

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Hi Justin , as far as charcoal systems go and in a lot of cases most people start off building a updraft “Gary Gilmore” Simple fire system due to the ease and speed of the build and plus all the pages and pages of questions and answers on problem solving , and once you have your feet wet ,your hands dirty and a smile of your face from ear to ear running an engine and once mastered you will then want to know how you can improve or move onto a larger system for a truck or larger generator/ lawn tractor ect .
You don’t mention what you intend to run on your charcoal gasifier stationary or truck/car ? once we know that we can maybe advise more on cooling and type of systems to aim for as there are many types and styles of charcoal gasifiers out there .


Hi Dave, sorry I completely forgot to mention that part. I have a generator I would like to run (it’s rated 8000w on propane) and I have a v6 pickup that I use around the farm that I would also like to convert.


Hi Justin , not a problem , why not start collecting items this week ready to build a updraft Simple fire system to test out on your generator than once you have the in’s and outs of running a charcoal generator then maybe move onto your truck .
if you want to be able to run your 8000 watt generator for say 4 too 5 hours run time unattended , then you will want a 44gallon size drums as your gasifier and a smaller 60 gallon type drum for your filter , no fancy pants basic set up gasifier get you running .
have a look on here for the discussion on “nozzles for charcoal gasifiers” there are links to some materials on there that will work well for a updraft gasifier .


Woops my mistake when working in metrics and imperials the drum sizes should be 44 gal and the 16 gal grease drum size .


Thanks Dave! Do I not need to install a cooler on the simple fire? Would it not make sense in order to try and get a little more gas shoved into the engine? Or is gas temperature not an issue on charcoal systems? I have several thermocouples and readers so if there was an ideal gas temp I could monitor it.


Hi Justin , no need for a cooler really, unless your pulling very hard for a long time and the charcoal level in your drum starts getting very low , the charcoal fuel in the drum will cool the gas down to a acceptable level .
I use flexi stainless steel pipes between the gasifier and filter and that also helps shed some heat , my system is the same as what i explained in the last post its a 44 gallon drum gasifier that runs a 7KW inverter generator on full load for around 4 / 5 hours at a time no problem at all till i am running out of fuel and then you will hear the engine start to hunt , that’s the time shut the engine down and refill or turn off for the day .


Hi Justin. Have you watched the Gary Gilmore videos on You-tube? Pretty much explains it all. I have built a couple simple fires, and a larger unit that I guess we have to call a Don Mannes. Gas temp is not a problem on them. I come out of the hopper under 100F Into a vacuum cleaner hose on both systems, as long as there is at least a half hopper of fuel. I’m sure it could less, but that’s as far as I have pushed them. Read the nozzle section of the forum. On a simple fire your biggest problems are going to be there. I’d also think seriously about trying out Matt Ryder’s new no-weld design. I’m liking the looks of that a lot.


Hi Justin,

Yes , there is a lot of info you’ve missed so far… :grin:

My style: based on G Gilmore, updraft, output gas temp about 40 C
Minimum filters
Ran about any engine trown at me, anything between 35 and 14000 CC so far…
Fuel size does matter, as does fuel quality, ( once you handle that well, then the rest is piece of cake )

Welcome to the dark side :grin:


Good Morning JustinH.
Welcome to the DOW.
Could you say what part of what continent you are on? So’s we will know about about your wood types.
Whether you’d be more comfortable with SI/metric; or Inch/Imperial measures.
Steve unruh


The charcoal making process burns off the tars and leaves carbon. The major design differences in wood gasifiers has to do with how to deal with tars so they don’t get to your engine and gum it up. Since you already burned off the tars in the charcoal making process, you don’t have to worry about the tars as much in the charcoal gasifier, therefore the designs are less picky and easier.


The only major thing to design right is the nozzle, a few of the designs tend to burn away without EGR or water drip. Most just make it a consumable part and the rest design them so the nozzle will last the life of the reactor itself and I think I’d put myself in that camp. A lot of the designs on here are almost a community project with everyone generously brain storming.

I’m in the process of making a downdraft charcoal reactor so I can run a small mix of wood or unfinished charcoal, and also make it more tolerant of charcoal with moisture in it.


Yes Sean you are right. Look in to the charcoal gasifer title next to the search eye grass. There is a lot of information to be found and how to build them. The one I am building is the down draft double flute. This unit has not been proven yet but the up draft, diagonal, cross flow are proven, and they work. The up draft flute also works. Many different designs to look at. Just search it out.


Hi Steve, I’m located in central/northern Canada. I have basically an endless supply of red fir (Douglas for). I’m definitely more comfortable with imperial measurements but I can do either.


Hi cody, I was actually curious about the egr, do you only use one when you are not using water drip? Or can you use both at the same time? Also are there any videos out there showing how to adjust the egr while running?


I haven’t had any usage of EGR yet but from what I have seen on here(and just about everyone else would know more than me) with EGR you would use a lot less water.
Both are good for keeping the reaction cooler I think. Both can be used on their own with their own merits. With EGR you don’t have to manually dial in drips per second and remember to turn it off. You’re literally just taking some of the exhaust gas out of the tail pipe and redirecting it into your nozzle intake.

Water can be as simple or as complicated as you like. Bruce in his MGB has a water mister to add smaller droplets and also probably so he can more easily control or shut down the water supply.


Fourth, charcoal production?

Setting up a nice charcoal making system is a good question. Making smallish batches of clean charcoal is easy. Learn to spot unburned pieces. In smallish batches, it becomes second nature. If hand crank grinding, unburned stuff can also be spotted. OK to miss a bit of this. The grinder is important. Your particles need to be about the size of Cashew nuts. Dust screening is also valuable. I would start making the charcoal first. The gasifier is the easy part.


Enjoy the ride Justin. So much info on the small engine/charcoal side it can be intimidating. Read lots. Fir is not a problem. I found the tractor ran best on soft wood charcoal; lots of surface area in softwood charcoal and less slagging.
Cheers, David Baillie (central Ontario)


Just a bit more regarding water vs. egr. I used both in my Corolla SimpleFire until my last cleanout and have used only water since then. I think I was cooling the reaction down too much causing a low power situation particularly when starting off and after idling a while. I’m using the flute nozzle, so I cannot visually monitor the reaction temperature. Is it possible to evaluate the temperature after the fact by examining the area around the nozzle at cleanout. So, at the next cleanout I’ll know if it got too hot. So far I can’t detect any problems. You can use both, but too much of either or both can reduce the reaction temperature too much and produce weak gas.


I had good luck with pine. May have had more power. However, this is small engine experience.