Alcohol Fuel Questions

[jarrodeu]

I have several questions on alcohol fuel I was hoping some of you guys could explain.

1. I think I read that running on alcohol fuel requires more of it to get the same power as regular fuel.

2. If this it true, how many gallons per minute would a race engine running alcohol fuel burn?

3. If running on alcohol fuel does that eliminate the need for ADI?

4. Could Nitrous Oxide still be used? Would it have the same effect?

5. Would running on alcohol fuel affect the cooling of the engine (lower operating temperature?)

6. Racers that used or that were going to use alcohol fuel that come to mind are Cobra III (?) Blind Mans Bluff, and thanks to Brad’s article Bardhal Special. Are there any more and why has it not been tried recently?

Thanks in advance,

Jarrod

[speeddemon]

Re: Alcohol Fuel Questions

Pond Racer.

[jarrodeu]

Re: Alcohol Fuel Questions

Pond Racer.

You know how much I feel like an Idiot right now. Reading an article on the Pond Racer is what spawned some of the questions. wake up Jarrod

Jarrod

[speeddemon]

Re: Alcohol Fuel Questions

You know how much I feel like an Idiot right now. Reading an article on the Pond Racer is what spawned some of the questions. wake up Jarrod

Jarrod

Its all that thin air up there in Colorado, dude..... :-)

[wyhdah]

Re: Alcohol Fuel Questions

Jarrod,

Some say it is twice as much but I know with turbo combinations that some motors are running almost three times as much. For instance our turbo motor on gas runs well (lean) at around 10.8 to 11.4 depending on length of the run. An alcohol combo a friend is running, and we will use for another car, runs lean at 4.1:1. as you can see this is almost three times as much.

This is a twin turbo combo as opposed to the single with the 11.4:1 but you can eliminate water (radiator), intercooler and what ever apparatus you have to support these systems (pumps, hoses etc.). I don't know the advantage of running ADI since you are practacally running a similar mix for fire. At that Air fuel mixture the exhaust will sometimes "slobber" alcohol.

It is strange to see a motor with the freeze plugs out of the heads where you can see right into the head where the water is supposed to be .

N20 would have the same effect but is pretty tricky to work out.

As for pound per minute, we run around 1100 pounds per hour on a 2500 hp turbo motor. This motor has eight injectors the alcohol motor has 27 injectors, three per cyl. and three directly in the intake tube. Do the math, it is a lot.

Later

[Ron101502]

Re: Alcohol Fuel Questions

Glad we had an expert to answer the question, you can see you'd have to carry 3 times as much weight/volume in fuel, need much higher flow fuel pumps, I expect you'd need a lot more boost or compression ratio, and probably stronger spark. I suspect, at least in carbureted engines, carb ice would be a huge problem. I've seen frost form an the injector "hat" of an alcohol dragster in 70 degree weather (I'm just a fan, I don't work on them). Remember the Pond was converted to gasoline before the accident. I believe methanol is pretty corrosive as well and didn't work well with composite construction, or so I've been told.

Ron Henning

[440_Magnum]

Re: Alcohol Fuel Questions

I have several questions on alcohol fuel I was hoping some of you guys could explain.

1. I think I read that running on alcohol fuel requires more of it to get the same power as regular fuel.

I'll take a crack at the ones I can:

Correct. The ratio (by volume) is just chemistry. It takes X many molecules of oxygen to burn a molecule of gasoline, and Y many molecules of oxygen to burn a molecule of alchohol. Y is about 1/2 X, so it takes about twice as much alcohol (by volume) to get a correct mixture with the same volume of air.

3. If running on alcohol fuel does that eliminate the need for ADI?

Alcohol is an inherently higher "octane" fuel than gasoline. That's not saying you CANNOT make it detonate, but it isn't as prone to detonation. If you did have an engine that had so much boost that it would detonate on alcohol fuel, what would you use for ADI? Probably straight water.

4. Could Nitrous Oxide still be used? Would it have the same effect?

Yes, and yes. What nitrous oxide brings to the table is a very dense oxidizer. Its like having liquid air you can feed the engine instead of having to compress the ambient air. When you start spraying nitrous in an engine, you MUST also spray the correct amount of additional fuel to mix with the nitrous and be burned BY the oxygen that the nitrous releases, otherwise the engine will go disastrously lean and the free oxygen from the nitrous will oxidize the red-hot metal in the engine very nicely. The "Mad Max" movies where they just crack open a bottle of nitrous with a rubber tube running to the engine is 100% complete and total fiction- it does NOT work that way! When using alky with nitrous, you have to inject over twice as much as you would if you were using gasoline, and for the same reason- it takes more alky molecules to react with the free oxygen released by the nitrous.

5. Would running on alcohol fuel affect the cooling of the engine (lower operating temperature?)

Jarrod

Heat load on an engine's cooling system is more nearly related to power output than fuel type. If an engine is producing 3000 horsepower, it needs to shed about the same amount of heat whether its running on gasoline, diesel, or alcohol. Yes, alcohol burns "cooler" than gasoline at any given pressure, but to really extract the power available, you need to raise the compression (or boost) for alcohol, and that commensurately raises the combustion temperature. Yes, there might still be a net reduction in cooling load, but its not like a 2:1 change or something really dramatic. Just my humble opinion, but usually the "cooling system load reduction" that people report when converting to alcohol is probably a sign they aren't really getting all the power they should on alcohol.

[jarrodeu]

Re: Alcohol Fuel Questions

Another question, say a 2800 HP merlin burns a combined 6.4 gallons per minute of ADI in a boiler for cooling oil and coolant. That's quite a bit. Is there anything else that would be better to boil other than ADI? If so, how much would it reduce the consumption?
Also could you cool both oil and coolant in the same boiler?

Jarrod

[Pick]

Re: Alcohol Fuel Questions

I believe methanol is pretty corrosive as well and didn't work well with composite construction, or so I've been told.

Ron Henning

With the IRL engines, we'd have to "pickle" the engine after we ran that day by running gasoline through the pump and injectors to help slow down the corosive effects of the methanol......otherwise the injectors turn to junk quite rapidly. (yes, as you can imagine, they ran slobbery rich as the gasoline replaced the methanol in the lines)

I'm not sure about the problems with composites.........just about everything on the top end of our engines was composite construction. (but the composite parts primarily saw dry air flow, not wet flow)

[Jim58]

Re: Alcohol Fuel Questions

If my memory serves me right ,

alcohol = about 77,000 BTU. per gallon.

gasoline = about 115,000 per gallon.

My question would be ...WHY alcohol ?
wouldnt you have to carry more for the same result.

***Ive got the answer***
(flashback to a previous life on the NHRA circuit)
just add some NITRO to boost the oxygen...VOILA.. top fuel AIRCRAFT
= ENGINE LIFE OF ABOUT 7 MINUTES.
OK sorry Ive gone too far

just my .02.....I love these threads

NO... Im not an engineer.... and I didnt stay at a Holiday Inn....

[georgelakesiii]

Re: Alcohol Fuel Questions

Once alcohol is mixed with water it will stay mixed and is hard to freeze at altitude. It will flow better than water by itself. In a dragster, you would typically run water or gas through to get rid of the corrosive effects of the alcohol that can damage the engine in as little as a day by eating up the babbit on the bearings which is a very soft metal.

Alcohol by itself is a little over 160 octane and burns in atmospheirc conditions, which helps stop detonation. The higher the compression, the more octane you need to stop or resist detonation. The benefit to the water is aside from not freezing easily when mixed with alcohol, is that water when turned to vapor as in a cylinder increases in volume by 1857 times which helps push the piston down. It also cools the charge down so that you can put a denser charge in each cylinder.

To see some of how this works, put an ounce of isopropol alcohol that is a 70/30 to 50/50 mix or so in a sparklets bottle and coat the whole inside of the bottle with it. Do this at night so that you can see the blue/white flame go slowly up and down inside the bottle. You will see it burn and not explode Do this with ONLY with isopropol. I know that you NEVER want to put isopropol in an engine, it is just readily available. You would only want to use ethanol or methanol in an engine. BTW do NOT use gasoline in the bottle or you will likely kill yourself with the resultant explosion. This is because gasoliine has a low octane rating meaning it is more likely to detonate. BTW you should change the oil in any engine after running alcohol in it as it will corrode.