Emergency Duty: Gasoline and Diesel Mixture

[WarthogARJ]

Hi all,
I'm a new fellow: nice forum

I'm interested to see how one could mix diesel into a gasoline motorbike engine in order to ride to the next place where you can get gasoline. In some 3rd world countries the gasoline distribution breaks down (no deliveries for a while), and you can get stuck on some long sections if you have a gasoline engine. But you can almost always find diesel, most long distance transport is by diesel: buses and trucks.

My bike can run on about 85-90 octane (antiknock sensor, fuel injected etc). I am estimating that I could add a small amount of diesel (up to 5-10%) to my gasoline before the low effective-octane of diesel (about 20) starts causing a problem.

I was thinking that maybe I could carry a small amount of octane booster (high concentration tetra-ethyl lead (TEL) etc) in order to add more diesel. It would be worth it to carry up to say 1 litre of octane booster as a sort of emergency reservoir (it's a tradeoff of weight/volume versus risk of actually ever needing it).

Some people in the UK (TetraBoost) sell TEL in an alcohol base. I'd like to get a higher concentration of TEL if I could. Or something even more powerful.

Any ideas?

Thanks.
Alan Jarvis

 

[901Memphis]

No, diesel won't run in a gas engine. Your going to end up damaging the pump or lines. Even a small amount of diesel will smoke like crazy, there's no vapors to ignite in diesel.


Can you get magic tank there? It's a gasoline substitute for temporary driving on warm engines

 

[Chris142]

Carry spare gas instead of additives to try to make diesel burn in a gas engine

 

[Ducked]

Kerosene (which is similar to diesel but a bit lighter) has been used as an octane-reducer for oldtech engines in the past, though there's some doubt as to whether it was actually effective.

http://www.mg-tabc.org/library/leadfree.htm

(Goes on a bit. Perobably unsuitable for modern engines and attention spans)

Desperate improvisation-wise, you could perhaps run a bottled-gas (I mean gas as in actual gas, as in propane/butane) into your air intake. Bottled gas is fairly widely available in North Africa, though small bottles less so). The gas has a high octane number and should improve ignitability, so it MIGHT give your liquid hydrocarbon cocktail a better chance of burning.

Improvised water injection might reduce knock but it might also interfere with ignitability.

On the whole improvised fuels seem likely to be create more problems than they solve. Octane boosters OK, and maybe a filter sock for the tank. Maybe also consider taking a lower-tech, less fragile machine on your trip.

 

[eljefino]

Until the 1940s they had low-compression tractors that would start on gasoline but then run on kerosene, still with spark ignition. They had horrible (4:1) compression ratios.

I've also heard of Briggs small engines running on kerosene with two head gaskets.

I personally have run a Briggs engine on white camp gas, it's unleaded gasoline without the additives (antiknock etc). It ran great, smelled good, but the gas is so volatile it all evaporates from the tank in the week after use.

These guys crossed the Congo in a diesel Land Cruiser and had trouble finding good diesel.

 

[fdcg27]

5-10% diesel will allow the engine to run just fine, although diesel does kill octane, as you already know.
I'd avoid carrying TEL, since it's quite toxic and your options for changes of clothing and a shower in the event of a leak will be limited touring a third world country on a bike.
One option might be to search online for airports near your planned route of travel.
Most third world countries have a lot of light aircraft use due to poor transport infrastructure and most of the aircraft used will be piston, since small turbine planes are too expensive.
Any airport should have a supply of avgas on which your bike would run happily.
The operator would surely part with some fuel for the right price, and British pounds, US dollars or Euro would be good to use anywhere and probably better than the local currency.
The avgas will be leaded, so you should probably avoid using it unless really necessary.
In the third world, your options will be limited.
If you leave the bike to hike for fuel, it won't be there upon your return, so running it on something not entirely suitable is probably your best option.

 

[WarthogARJ]

Hi,
Thanks for these.

Maybe I wasn't clear enough. This is not a permanent issue, I mean I did a trip thru Africa on the East side (4 months/25,000km) and I only ran out twice. But was able to get enough to carry on.
But it was a big hassle both times.

Lower-tech, less fragile? Dang. It's an HP2 Enduro: can do the Paris-Dakar on the beast. I don't think "fragile" applies to it..:-}. It's the same for just about any reasonably sized bike: they are all limited to a lower limit of about 85 octane. Even a little 125 won't run on 65 octane.

Diesel and gasoline are both blends of various hydrocarbons, and there's a fairly big overlap between them. I really think the main issue to a higher diesel/gas ratio is pre-ignition. I'm not talking 80% diesel. Even 40% would be a big help. But even at 40% diesel the octane equivalent would be pretty low: about 67 octane. I'd need about 1.5 liters of TetraBoost to get that back up to 85 octane. And sure, maybe carry some more volatile material to make the mix behave more like gasoline. Ether maybe.

But you cannot solve this by camping gas bottles, or more fuel. I'm already maxed out there. I increased my range to 30 litters, with an extra 4 liters on top.

I'm looking for a clever way here: using a bit of science/engineering know-how. Be very nice to be able to extend my range by an extra few 100 km with some sort of secret Colonel Sander's mix....:-} Being stuck several hundred km short of the next petrol depot can mean a day to get there and back. And it's not usually a great idea to leave your bike on its own. This is not Kansas, Toto.

Alan

 

[eljefino]

Are you going to be on paved roads? Can you hypermile coasting down to 20 mph then kicking it on and accellerating to 50 and repeating?

The Army has a Kawasaki motorcycle modified to run diesel...

 

[WarthogARJ]

Originally Posted By: fdcg27
5-10% diesel will allow the engine to run just fine, although diesel does kill octane, as you already know.
I'd avoid carrying TEL, since it's quite toxic and your options for changes of clothing and a shower in the event of a leak will be limited touring a third world country on a bike.
One option might be to search online for airports near your planned route of travel.
Most third world countries have a lot of light aircraft use due to poor transport infrastructure and most of the aircraft used will be piston, since small turbine planes are too expensive.
Any airport should have a supply of avgas on which your bike would run happily.
The operator would surely part with some fuel for the right price, and British pounds, US dollars or Euro would be good to use anywhere and probably better than the local currency.
The avgas will be leaded, so you should probably avoid using it unless really necessary.
In the third world, your options will be limited.
If you leave the bike to hike for fuel, it won't be there upon your return, so running it on something not entirely suitable is probably your best option.


Heh heh.
Full points for being creative.

The problem is when you run out, it's in the middle of nowhere. No airports, no nothing. But there ARE buses and trucks. Is pretty frustrating to see them, and not be able to use their fuel at all. Is a bit like dying of thirst in the ocean.

Having a spill of TEL is not really a big issue: I can put it in something that won't break.

I'm thinking I might just do a comparison of a typical diesel to petrol by component. And see where I need to beef up the mix a bit. The overall calorific value is OK. Volatility (by vapour pressure) on the low side. Pre-ignition is the worst factor.

So far nobody I've asked has looked at this very analytically. I know I can boost the octane by adding enough TEL. But I wonder if that's enough, or if another issue will crop up.

Blocked fuel lines is not it: diesel and petrol are going to be the same. Injector issue? Well why? Diesel engines use injectors.

Volatility? I don't think so: I mean that's what pre-ignition is to some extent. The diesel WILL ignite, but too quickly. It will knock.

You can run a diesel on pure veggie oil: that's REALLY different from diesel. So how far from petrol can you go in a petrol engine? What factor determines how far?

I know the octane rating of a diesel/petrol mix is really bad. So what ELSE is critical?

Anyone have factual values?

Alan

 

[Cujet]

In the 1980's, I rode a Yamaha 250 "exciter" motorcycle on a mix of diesel and gas. Had to, as I was out-o-gas in rural Florida, in the middle of the night, and fuel stations were closed. (not poor planning, a good girlfriend occupied my time ,,, ) I was able to get a bit of diesel from a truck driver and add it to a bit of gas. It ran, but smoked and knocked like crazy. I made it home without trouble. I added gas the next day, and went on my way. The bike continued to run just fine for the remainder of the time I owned it.

 

[Oldtom]

Hi Warthog - Welcome to the forum. My dad used to tell me about running cars on kerosene during the Great Depression. This may be some help to you. Dad was born in 1911 and turned 18 when the Depression really hit. He and a carload of friends would drive from Pennsylvania to Daytona Beach Florida to watch the races. This was a 1200 mile trip over some dicey roads. They were often broke on the return trip, so, they fueled the car with cheaper kerosene. Dad said the important thing was to keep the motor running while refueling, as the hot manifold helped vaporize the kerosene. They took turns driving and never shut the engine off, as it would not restart when cold. Bear in mind that cars in the 1920's were low compression, which probably helped reduce detonation. I think your idea of mixing diesel and gas is a good one. Maybe try the mixture at home to see how it works before traveling to the boondocks?

 

[expat]

I'm thi king you might want to experiment a little while you are in the UK.
I guess the worst that would happen is some pre-ignition. If you were around in the UK, during the time of pool petrol in 1950's
You would know how long an engine can survive while pinking like crazy. Back then, many hundreds of miles.

I assume your bike would do the same on a diesel mix. Not ideal, but better than walking.

 

[Ducked]

Originally Posted By: expat
I'm thi king you might want to experiment a little while you are in the UK.
I guess the worst that would happen is some pre-ignition. If you were around in the UK, during the time of pool petrol in 1950's
You would know how long an engine can survive while pinking like crazy. Back then, many hundreds of miles.

I assume your bike would do the same on a diesel mix. Not ideal, but better than walking.


Water would reduce pre-ignition. It'd reduce pinking as well. (I think pinking is detonation, not pre-ignition, though it sounds as if it should be. Engines generally survive detonation for a lot longer than they survive pre-ignition.)

You'll be able to get water anywhere there are people, even in the desert, otherwise there wouldn't be.

Ideally you'd want distilled, but in a real bind I suppose bottled water would do. Artesian water is often salty so often wouldn't be suitable even for emergency use, unless you were boiling it on the machine and using the vapour.

If using water you'd certainly have to experiment beforehand. Your options would be getting some of it into the fuel (perhaps with alcohol as a bridging solvent), or getting it into the air as droplets or vapour. If the inlet manifold is hot enough, drops in there might produce vapour.

You could perhaps use one of those (ultrasonic?) mister gizmo's that people use in water features/essential oil dispersers. IIRC some of them take 12V.

Steam generated from exhaust heat could also be used to pressurise a sprayer, or maybe you could have a manual (tyre?) pump, but that's more engineering.

As I understand it the Paris-Dakar is a race with big-money sponsorship and support teams, so not very relevant to your real-world scenario.

 

[expat]

"You could perhaps use one of those (ultrasonic?) mister gizmo's that people use in water features/essential oil dispersers. IIRC some of them take 12V."

I did once experiment with those. But found the water quantity generated was no where near the amount required to effect octane deficiency.

However I do remember my father telling me, when he served in the desert of North Africa during WWII, vehicles would have a water trickle into the carbuertor to prevent ?? whatever. When driving in the heat and sand.

 

[Ducked]

Originally Posted By: expat
"You could perhaps use one of those (ultrasonic?) mister gizmo's that people use in water features/essential oil dispersers. IIRC some of them take 12V."

I did once experiment with those. But found the water quantity generated was no where near the amount required to effect octane deficiency.

However I do remember my father telling me, when he served in the desert of North Africa during WWII, vehicles would have a water trickle into the carbuertor to prevent ?? whatever. When driving in the heat and sand.


Hmm..maybe the water idea isn't practical, though the WW2 story is interesting. Hadn't heard that before.

My impression is that the OP is going to be lucky to get the analytical/theoretical response he's asking for, since octane / knock control is a pretty empirical business.

Octane number is defined operationally by performance in a test engine, and I'm not sure anyone would be able to confidently predict the performance of diesel/petrol mixtures if they hadn't tested them.

I did once meet someone widely believed to be rather clever who was planning to use such a mix in a racing rotary engine application, but I never heard how (or if) it turned out.

 

[Jetronic]

Originally Posted By: WarthogARJ
Originally Posted By: fdcg27
5-10% diesel will allow the engine to run just fine, although diesel does kill octane, as you already know.
I'd avoid carrying TEL, since it's quite toxic and your options for changes of clothing and a shower in the event of a leak will be limited touring a third world country on a bike.
One option might be to search online for airports near your planned route of travel.
Most third world countries have a lot of light aircraft use due to poor transport infrastructure and most of the aircraft used will be piston, since small turbine planes are too expensive.
Any airport should have a supply of avgas on which your bike would run happily.
The operator would surely part with some fuel for the right price, and British pounds, US dollars or Euro would be good to use anywhere and probably better than the local currency.
The avgas will be leaded, so you should probably avoid using it unless really necessary.
In the third world, your options will be limited.
If you leave the bike to hike for fuel, it won't be there upon your return, so running it on something not entirely suitable is probably your best option.


Heh heh.
Full points for being creative.

The problem is when you run out, it's in the middle of nowhere. No airports, no nothing. But there ARE buses and trucks. Is pretty frustrating to see them, and not be able to use their fuel at all. Is a bit like dying of thirst in the ocean.

Having a spill of TEL is not really a big issue: I can put it in something that won't break.

I'm thinking I might just do a comparison of a typical diesel to petrol by component. And see where I need to beef up the mix a bit. The overall calorific value is OK. Volatility (by vapour pressure) on the low side. Pre-ignition is the worst factor.

So far nobody I've asked has looked at this very analytically. I know I can boost the octane by adding enough TEL. But I wonder if that's enough, or if another issue will crop up.

Blocked fuel lines is not it: diesel and petrol are going to be the same. Injector issue? Well why? Diesel engines use injectors.

Volatility? I don't think so: I mean that's what pre-ignition is to some extent. The diesel WILL ignite, but too quickly. It will knock.

You can run a diesel on pure veggie oil: that's REALLY different from diesel. So how far from petrol can you go in a petrol engine? What factor determines how far?

I know the octane rating of a diesel/petrol mix is really bad. So what ELSE is critical?

Anyone have factual values?

Alan


Get the bus or truck to pull you... or bring you to a gas station...

 

[Shannow]

I honestly don't think that it can be done reasonably with a modern engine management system.

Back in the day, when Sir Harry Ricardo built his 200hp tank engine (6 cylinder, 186 c.i. per cylinder) that ran on kerosene, he was limited to 4:1 compression, but still made an amazing 0.45lb/hphr.

Key was to get vaporisation of the fuel...then you can run lean to reduce the autoignition potential.

Your ECM won't let you run lean, and you won't get the heat to vaporise, and a modern 95RON compression ratio won't help.

Personally, I think older technology might be what you need for this adventure.

Napthalene is a relatively low spill octane enhancer, not sure that a backpack full of it would solve in diesel really quick. Acetone and MEK would help, but not really that useful in the heat.

 

[fdcg27]

It's very common for Cubans to run old American iron on diesel.
The engine is started on gasoline and then switched over to the diesel tank after it warms up a bit.
These are old, low compression engines, though and obviously have no engine management system of any kind beyond a distributor and a carb.
I have run OPEs on a blend of about 50% diesel just to use up what I had to drain out of the tank of a 123 that I had to change the fuel line on. The mowers ran fine, although they did experience pre-ignition, as evidenced by their willingness to continue running as diesels when switched off. These were also low compression side valve engines, nothing like your bike.
Experimenting with diesel while still in the UK is probably good advice.
Try various blends and see what happens.
I would also think that tires would be of significant concern in rural Africa, but that's another matter.

 

[Pontual]

I was reading this yesterday and did 5% in my Ninja ZX9R, with 12 to 1 CR. Run 150 miles without any difference. Tip of exhaust got a litler darker and thats it. 10% maybe feseable, but thats with you. I believe that at 5% it would burn lubricant 2 or even 4 stroke, imagine fuel (diesel)...

 

[A_Harman]

Originally Posted By: Pontual
I was reading this yesterday and did 5% in my Ninja ZX9R, with 12 to 1 CR. Run 150 miles without any difference. Tip of exhaust got a litler darker and thats it. 10% maybe feseable, but thats with you. I believe that at 5% it would burn lubricant 2 or even 4 stroke, imagine fuel (diesel)...


I really appreciate this effort: "One test is worth a thousand expert opinions."