Hello all, I’m curious as to why syngas in general doesn’t run well at higher RPMS, is it just an issue with timing? Or possibly fuel production from the system itself? What’s the main problem and can it be overcome?
I understand it’s a slow burning gas but has anyone here attempted to tune their vehicle for it? I was thinking of buying a 4.3l 97 S-10 and dyno tuning it to run off of woodgas but I’m worried about the aforementioned problem.
Bobmac was just saying last weekend he can run out his Dakota to 4500-5000 rpm no problem, I don’t think it’s a matter of tuning the engine for high rpm woodgas, it’s sizing the choke plate for what you want the engine to do at what rpm it will do it. Wayne has talked about this before such as his v10 is a low end grunt work horse with the gassifier set up according, while his Sunday driver Dakota is happy on the freeway at 70+mph. Tuning the gassifier for the demand you will use it for. I havnt logged but a few miles on wood yet but my v8 mini truck has plenty of extra ponys to spare so winding up the motor isn’t needed the truck moves just fine with a small choke plate in it. Once I learn a bit more about how it drives if I want more out of the engine I’ll play with the choke plate and open it up some more. The tuning part is accounted for in timing adjustment on most the trucks here that are drive down the road wood to shaft power. Jo in his Volvo has very little timing adjustment but it doesn’t seem completely needed in his application the car moves very well without a big bump in timing adjustment. The problem I see with dyno tuning it is woodgas is not consistent in it’s production. One hopper of wood to the next will change the gas some, be it from soft wood to hard wood, or a loose or tight char bed, or a sudden leak, or running at higher temperature. A more stable gas would be the char gas guys, that system may be more tunable but even then, water content from one batch of charcoal to the next will change up the gas production. Not trying to discourage you in the slightest, but it would be very difficult. All the same I plan to dyno my truck some day just for the fun of it wood vs dino
When my Mazda still ran I could get up to 5000rpm on charcoal. It was an updraft charcoal gasifier though so it basically has no turn-down ratio. 6000 rpm was end of the world redline for that little 2 liter OHC engine.
The Wayne Keith gasifiers are very generous for RPM if you’re looking for a raw wood setup.
Back in 2011 I participated in some speed trials out on the Salt Flat . I did some experimenting before going out there to try to get the truck to the fastest speed from dead still start to a measured mile . The truck would keep gaining speed way past 4000 rpm but I found that if I would shift into a higher gear at 3900 rpm I could get to the fastest speed for this truck. If I remember correctly I was using pine chunks for fuel.
I’m wondering why you are looking for the higher RPM range Thomas. Beyond mid-range rpm may deliver more power but torque will fall off rapidly. With a truck I would always be looking for more torque. I would be inclined to find more gears so I could stay in that torque sweet spot and still get more MPH.
My thoughts exactly with my motorbike build. Just because the flywheel in my 196cc LETS me rev 9 grand doesn’t mean I’m making my best torque anywhere near that. I’m thinking of either making an automatic centrifugal 2 speed jackshaft or a Comet style CVT. Either way would let me stay in the mid range.
Woodgas burns more slowly than petrol. At high RPM that becomes a limiting factor. Basically at high RPMs the fuel isn’t in the cylinder long enough to fully combust and deliver that energy to the engine.
On the positive side…. Woodgas can run with higher compression vs petrol without knocking, but the RPM limitations still stand.
I posted elsewhere but the best “tune” for woodgas, at least in theory, is to increase compression (more power) and advance the spark timing (burn starts sooner so RPM can be a little higher). That kind of tuning prevents dual fueling with regular gas but more power on woodgas from a given engine.
This little honda clone will be dual fuel with alcohol as my starter and emergency backup fuel. Engine already has a 20 degree spark advance built into the flywheel, I could advance it further with a new flywheel key. I want to say it has a higher compression cylinder head as well but I can’t confirm that, my wrist dyno is my judgement aka harder to pull start it.
Thomas, from what I understand a higher compression ratio can squeeze more power outof the same amount of woodgas. All good, minus the effort.
However, more power via rpm will require more woodgas and the gasifier has to be able to deliver without overheating. The problem in a vehicle application is you need a small enough gasifier to make clean gas at low demand (idle).
You asked two category of questions. Everyone so far is responding to your first Gas questions.
On the done-it with a GM 4.3L (V-6) there had been three fellows I recall here on the DOW.
Mike LaRosa; Tom Collins and Jan Axelsson.
MikeL is deceased. He did like his gasified S10 a lot. His topics and results are still retrievable here by the Search stacked-paper top tool.
Tom Collins works can be search up too. I figure if he wants, he will chime in here too with his gasified 4.3L pickup experiences.
Here Is Jan Axelsson project topic:
The current 801 posts on this topic can be intimidating.
Easy. Bottom of his first introduction topic is a blue block tool: “Summarize This Topic”. Then only 100 posts to view and read. And the pictures posts get priority.
Now do some reading. Many will not comment until you’ve done some filling in work. The same caves explored for the tenth-hundredth time get mighty wearisome.
Air mixed fuel gas energy release (burn) rate is affected by at least 10 factors only in-engine, loaded, duplicatable. Forget open air burn results. And flares staring. Throw out octane musings. Use it. Track results.
Burn, hole-a-piston; and you went you far. Ha! I learned to stop pushing-it seeing aluminum spatter on the sparks plugs. Saab V-4 street racing. Cast iron heads and block - so had to be the pistons.
Cody - yea alcohol has a very high octane rating and would avoid pre-ignition or knock that would make regular 87 octane petrol a problem in a high compression engine.
I debated mentioning alcohol as a dual fuel or starting fuel in my reply above. I wasn’t 100% sure about alcohol’s flame speed and how it would handle the early spark that woodgas likes. Based on your experience it works well, so I’m filing that away.
Alcohol will want to absorb moisture from the air but otherwise stores indefinitely in a sealed container, ideal for a fuel you use sparingly. E10 (90% dino petrol, 10% alcohol) does seem to want to eat aluminum carbs. I’m not sure if E100 (pure alcohol) does the same but thats something to watch out for. And in a pinch there is a pretty well known “recipe” for making your own alcohol, for those that want to maximize their independence.
I can still start the engine on high test pump gas so it isn’t too hot of an engine. I just consider alcohol as the main fuel because of the air intake control. Im hoping to get a dyno hub to charge a 12v battery so I can also hard start the reactor without liquid assistance on top of powering my lights.
Also I think if you added a smidge of 2 cycle oil or some Marvel Mystery Oil it could prevent eating up an aluminum carb? Not sure about that just an educated guess.
The guy that does various reviews on his Project Farm -Youtube channel has a see through cylinder head that he uses to show flame spread on various fuels. Pretty interesting. I’m blaming you SteveU for the many hours I have now spent watching these videos. Not really wasted time though so no hexes or curses will be cast.