Cyclone Challenge

Hi Wood Gassers,

I am getting ready to build a run of my largest cyclones, the 2" inlet/outlet, 6" swirl body units.

These hit their stride at 70cfm/50 shaft horsepower which is what a pickup uses under light acceleration. I personally feel that the drop box advocates are missing out so I would like to offer a challenge to anyone who has a vehicle running on wood with a 318’ish size engine. I will give you a $250 cyclone in exchange for a valid before and after comparison. All of my cyclones clean down talcum powder size particles so I am betting that I can drastically reduced the amount of stuff that enters your gas cooler train if the cyclone is placed directly after the gasifier.

Any takers? I would do this myself but my state inspection laws are so painful that it is doubtful that I will ever do a road worthy wood gas vehicle.



oh man, I would love to do this with my little Toyota, though it’s not a 318, and it’s not a project I could get done until next winter.


I am building five of them so there may still be some on the shelf when you are ready. These are NOT my hottest seller. I think I need to prove them before they get widely accepted.

My larger application will come in a couple months. These are meant for my beastly Elizabeth which is still taking shape in the dark corners of the barn.



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Well, I’ll keep you posted. I know once we get the generators going, the toyota’s going to be the next project.

HI Wood Gassers,

We have a taker! Bill Schiller is going to take me up on my offer. Bill has a vehicle with a 318 V8 which gets 16mpg at 65mph. That means that at a gas strength of 150 Btu/ft^3 his engine will need 52.3 cfm of wood gas to receive the same chemical energy input as running on gasoline. At that speed the vehicle is putting roughly 37hp to the pavement.

If you want to play with numbers for your vehicle my calculator is here:

Now I just have to finish cutting metal and make good on my end of the deal.



Hi Wood Gassers,

Me being me, I couldn’t just build a pile of 6" cyclones. Instead I outfitted them with 400cfm 12V cooling jackets. I was looking at the jacket and blowers this morning thinking, “This isn’t going to cool gas, this is going to cool global warming!”

The cyclones should be back from the welder tomorrow. I can’t wait to start getting data from mine.

Get ready Bill! You will be up soon!



Bill are you going to go with a cyclone instead of a media type filter or both?

Hi Wood Gassers,

I just finished Bill’s cyclone. It suffered a little “feature creep” as we call it my world. I was planning to ship just an off the shelf unit like this:

Instead I am shipping this:

I added a spin on ash bin and 248cfm cooling jacket. Obviously it’s not a $250 cyclone anymore but with risk comes reward. The 400cfm jackets will be standard but the fans are taking a while to get here and I want to be sure Bill has this in hand in time for Argos.

Some people have expressed a little worry that this is not big enough for vehicle use. Other than a bunch of numbers, I would remind everyone that my wife’s Suburban has 2.25" exhaust pipe and this has 2" piping for just the fuel flow. It’s all good to me.

This will get packed up this afternoon. Bill!! You are up! Try to hurt it!



Hi Stephen,
Are the fans arranged one blowing in one out or both in and the air bleeds out?

Hi David,

Both fans suck in cold air so the fan motors stay cool. The air exits the rear baffle at the top and bottom.


Alright Stephen! What a way to put the drop box to a real test. I personally LOVE the cyclone for being efficient, compact and help with cooling. And yes, your “feature creep” is a little over the top, but why not? How can we advance if we don’t keep comming up with ideas we think are better and then testing them. I’ll have my 4" cyclone at Argos and will be anxious to compare the two designs.
Thanks for stirring the pot and being willing to make the offer you did.
Gary in PA

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Hi Gary,

Thanks. The gas cooling numbers are impressive when you air cool the cyclone. I have seen over a 400F reduction in gas temperature:

But don’t give me too much credit. There is a certain self serving marketing aspect to this.


Hi stephen.
The BTU evacuated by the fans they would not inject into the gasifier?
Perhaps too complicated to build and little energy saving?

Hi Thierry,

Absolutely the heat should be put back into the gasifier. On the Victorias I use the ash bin walls as a heat exchanger surface. Unfortunately, being a small simple machine there isn’t a lot of space to mount heat recovery equipment.

On the big Elizabeth machine I am recovering the heat and trying to limit the gas exit temperature to about 150C. I want it to be just hot enough to keep the cyclone dry and the powder flowing. That machine will not have a cooled cyclone. That is why I designed the air coolers as strap on accessories.


Stephen, What are you asking for your largest cyclone ? (straight cyclone no fans) Does it have a cone set inside of it ??? Thanks, Mike LaRosa

Hi Mike,

Plain Jane 6"ers are $250 with just a capped 2" nipple on the bottom. I have three available if you want one.


Stephen, I will call you on the twisted pair next week when I get a break … I have a busy weekend … The cone in the bottom allows the double vortex to form. this throws the fines out better. Only problem is it doesn’t transfer as much heat. I generally run my cyclones as the first part of the system after the heat exchanger etc. etc. Also they stay hot enough to not get water in them … Although APL has something that appears similar, there is a stainless sheet metal cone insert in them … I build from junk so is hard to do but you have nice flanges I wish my pictures were still on the web or I’d send a couple of links … Regards, Mike

Looks really good Stephen… Can’t wait to see how it works out for Bill.

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Gasifier stuff in the kitchen! Either you’re a bachelor or you have a very tolerant wife! lol

She works at the local hospital and I do engineering consulting and metal fabrication from the barn. Rest assured it is ALL cleaned up before she gets home.