Towing long times on wood gas

i want to tow loads long distances. i understand that there is an overheating issue with average style gasifiers, where can i find info on building a larger style gasifier? and… for slow runs…wouldn’t having a suction fan on, keep the fire hot so as to not create tar at slow speeds? hoping to start this build within a few months…trying to gather parts right now. some info would help. thanks.

Good morning Shane and welcome to the DOW.

What size vehicle and load are you planing ? Also what speeds do you plan to drive ?

What do you consider being long distance ?


Truck, Trailer, load and everything about 12 thousand pounds…and at highway speeds…with some city traffic. state to state runs. I have an old school bus with a 460 in it. Will be pulling wood and camping supplies on a trailer. The gasifier may be on the roof or more likely on the trailer. Its going to come down to design. So I figured I’d start planning, now.

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Headed to work now…check back around 6.

Hello Shane

I have been thinking about your plans all day and just haven’t come up with any good ideas .

Assuming highway speeds are 60-70 mph it would take a huge gasifier to supply enough gas to go those speeds . Even if you had a gasifier big enough to make plenty of gas your 460 motor would be rated to about the power of a 300 cid motor because of the lower btus of wood gas . Also with a gasifier that big any lenght of driving speeds under about 30 mph would most likely tar up with you .

If you mount a gasifier on a trailer pulled behind the bus you will need to work out a lot of details about how to keep watch on the temps and vacuum readings.

Driving state to state would require a lot of wood . Driving those speeds with the profile of the bus and trailer weight you would need about 3 ponds of wood per minute .

I think if I were building a project like yours I would build a gasifier that would fit inside 55 gallon drums and would work well at the lower power demands and plan on hybrid driving with gasoline for the faster speeds .



Wayne I have been thinking about this too although I haven’t build a gasifier myself I can’t envision how to make the gasifier fit well with the bus. I keep coming back to the video of you hauling a trailer full of round bales or a trailer of cattle and think if I wanted to make cross state trips I would rather setup a dodge v10 and trailer a camper. It just seems a lot easier to haul the gasifier and wood in the bed of the truck with a camper on back you can drop in a campground.

Hi all. Worked till 8…what a day.I still think there may be a way. I read a title to a post where a guy was saying something about putting 2 standard gasifiers in his truck. Kinda makes sense to me. Wayne if your truck can pull all those round bails that many miles before getting too hot, well then it seems to me that if you had had a second gasifier to run while the other one cooled down…that it just might work. So I am guessing the same principal would adhere to the bus. So the question is…would 2 gasifiers work to get the bus across the country? Why stop at 2? Why not 3 gasifiers? Or 4? My bus has a home made full length rack up top. I could put the wood up there. I don’t know how much a 1968 ford school bus weighs fully loaded…nor how much a trailer would weigh with 3 or 4 gasifiers on it. But I am thinking it couldn’t weigh as much as your truck and trailer with 3 rows of round bails on it. I might mention that the school bus has been converted over to a fully functional motorhome complete with washer and dryer,…heck everything. I really want to run this trip threw the south strictly on wood gas. Thought on multiple gasifiers??? For the cool-down factor ?

Full size school bus tips the scale at something over 18,000 pounds. You’ve probably added a good bit of weight with the conversion.


I like to think of engineering as the art of compromise. So, I would make the bus 1/3 or less RV. The very rear would have open sides for the gasifier. In between would be the fuel supply. You’ll have to work on the turn down ratio, insulation, water injection, lower travel speed, gas bag on the roof or what ever.


Hi Shane, running one gasifier in my truck is all I would like to operate at one time. Trying to balance and monitoring two of them while driving down the road would be more than what I would like to try to do. My truck has a auto wood gas mixer and hopper temperature alarm, that make it easier to drive.

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Welcome to the site. I’ll reiterate what a lot of folks have already hinted at… this is not an ideal use case for woodgas.

It’s kind of like the old saying, “pick any two”: highway speeds, heavy loads, long distance.

Wayne’s V10 Ram can haul heavy loads at highway speed, but only for very short distances.
Mostly he chooses to run heavy loads at low speeds, or unloaded at medium speeds.
The standard woodgas Daktotas run highway speeds, and can go long distances - with very light loads.

Trying to do all three is simply impractical. I don’t mean to be a wet blanket, but I won’t mislead you.


All that aside, you should definitely start with a regular gasifier build. Walk before you run. Once you build a woodgas truck and put 10K miles down, you’ll have a much better idea what this project entails.


I think where a lot of people are having a problem, is the gasifier getting REAL hot. Has anybody came up with an idea to cool the thing down? My first idea was, put in a sprinkler to spray into part of the fire. Another idea I had was to put a tube into and then out of a dry ice container…then pump air thru it into the fire. Course, the sprinkler idea may just wet the fuel too much and defeat the purpose…and dry ice?..I have no idea if it would work. The other idea was to just let it get hot…just build a unit that if tuff enuff to withstand the heat. I can see fire brick lining the inside. Maybe fire cement for the fire grate too?

Two things make quality woodgas. Charcoal and heat. Stealing one of them from a gasifier will make worse gas. Waynes gasifier si so sucsessful becouse he traps all the heat in right places.

Allso, when any gasifier gets too hot, it stops being a gasifier. It just becomes a wood burner. At this point the gasifier is overdrawn with air and burns all the gas it produces, resaulting in high temps.

l think the only way wuld be 2 gasifiers or a gasifier that acts like 2 gasifiers.

You can do a simple calculation to see if the project is realistic. This is a rough equation for calculating fuel needed for a trip:
(Petrol consumption per mile in liters) x (number of miles) x 2 = (weight of wood neaded in kilos)

(Weight of wood in kilos) x 3 = (volume of wood in liters)

Do a calculation for your needs. If this works for you, continue, otherwise l wuld think of something different.


Hi Shane, heat is your friend when making good wood gas with no tar in it in the gasifier. But heat is also your enemy, it can melt fire brick, Stainless steel, mild steel if you get it to hot trying to make more tar free wood gas then your gasifier is designed for. We call it over pulling the gasifier.
The other enemy is tar, it can mess up a engine and destroy it. The WK Gasifier has the Best Turn down Ratio that has ever been built. What I mean is that at a Idle it produces no tar if run correctly, and it can idle for a long time. The secret is in the building and design of it.
Now when running only on wood gas you lose 25% to 30% horse power in the engine, this is why there are limitations on what you can do. You want to drive fast, then lighter weight loads and shorter distance (HEAT becomes your enemy by over pulling the gasifier). You want drive long distances, moderate loads like a light trailer with extra wood. You will not be breaking any speed records getting there, hills become a problem going up them, if you put the pedal to the floor (HEAT becomes your enemy again same problem over pulling the gasifier. So you shift down in gears and go slower up the hill. Now you want to go long distances and with heavy load vehicle, first of all you will need lots of wood to feed your gasifier, and your speed will be moderate to slow, not even highway speeds at times. This is all on wood only driving.
Now here’s how you can do it. By hybred driving, running your vehicle on gas and wood gas at the same time. That is how we haul heavier loads and get up the hill too, but some times not at highway speeds.
Having the right size vehicle and engine that can run on gasoline, wood gas, or both.
It still depends on the vehicle and engine size in that vehicle and sizing your gasifier for that vehicle for your needs.
Like Chris said you have to pick any two of the three.
We have all been working on getting to that point of having all three in one vechile and be practical driving on wood gas.
I am still working on improving my gasifier system. But my 92 Dakota from the book will never have all three just driving on wood gas only. And not on gasoline ether, because it is a light duty truck.
By the way Shane, this wood gas and charcoal gas gasifier building is very addictive. That first SWEM on your face is amazing when you see it in the mirror, and all the rest will look great too.


I went through a brief calculation. Your 460 engine will provide max. 100 HP on wood gas. Fuel consumption will be around 200 pounds per hour. I do not see a problem with tar as long as the hearth is designed as a cone that allows sufficient heat from idle to top speed.

But if that power limit and fuel consumption will be practical for your project, that is up to you.

Best regards, Daniel


Daniel; I may be wrong but I believe this is the first posting I have seen by you. We have all seen your gasified Opel, and Model A and maybe a tractor, so we are familiar with your expertise. I would like to say “welcome” to DOW TomC

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What Mr. Tom said :grinning:

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Hi Daniel, I see you joined up May 6th. It is always nice to have experienced new members input on the DOW site. Welcome and I hope to here more from you. Please set up some threads of what you have built, so other members can learn from your experiences. That’s the beauty of DOW, everyone sharing, learning and experiencing the thrill of wood or charcoal gasification.


What Bob said.

Logic and innovation are the greatest features of this group.


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If I were to attempt a wood gasser to do long heavy hauls, I would do the following:

  1. Gasifier made from all stainless with ceramic insulation in a slightly oversized tube in an effort to keep as much heat inside the charcoal zone as possible, and allowing very high temps to be reached without melt down.

  2. I would employ Wayne’s heat recycle back into the reaction zone, but I would draw the residual heat from the gas stream after it exits the grate, and also from the exhaust system like Wayne also does.

  3. I would employ Ben Peterson’s pyrolysis accelerator and work to maximize the heat transfer to the wood chunks, and make the zone as big and hot as possible

  4. Instead of a fixed restriction, I would experiment with a ceramic iris valve. Having control of the restriction size while you drive could be a real boon allowing control of heat build up while heavily loaded or at high speeds, ultimate gas production, and greatly amplifying the turndown ratio by closing up the restriction at idle. This is something I feel could really jump the real world performance of a gasified vehicle.

  5. I would buy a truck with the largest, most powerful engine available, and ideally supercharge it.

This truck would eat wood like there’s no tomorrow. The only way to get a lot of range is to use a fuel that could be auger fed into the gasifier from a separate hopper like wood pellets. At that point you are on your own with making all this work as there is not much out there as far as prior art goes, and there are known challenges with pellets you would have to overcome. You’d end up being a woodgas pioneer …:thinking: