FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: plovett on November 22, 2019, 08:52:57 AM
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When you inject a methanol/water mixture into an intake tract, as in a supercharged application, does the methanol add a combustible component? Or is it just for cooling?
thanks,
paulie
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Methanol in itself is a fuel. So yes to your question.
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Methanol carries oxygen with it also.
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So does it affect the air/fuel ratio then? Or is the amount injected primarily for a cooling effect insignificant in that respect?
thanks,
paulie
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Yes it does. It really depends on what meth/water ratio your running and how much total injected. A good reason to use Lambda in tuning as 1 is stoich no matter the fuel or combination of fuels.
But with it comes cooler (more) air due to latency of evaporation (of which methanol is more so than water) so it might not need much of a change from where your at now, as said depending on mix and quantity.
I'm currently setting up a twin stage system for my LPG turbo project. Can't wait to try it but its winter now so I have stopped fiddling with it :-\
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If I was going to mess with that, I'd make sure I had a Oxygen sensor to make sure it doesn't run to lean when under power.
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Running my ECTA car, (E/F CC) I have a 'spray' system that uses methanol as the fuel along with the nitrous oxide. It's literally impossible to add too much methanol. unless you go so far that there's enough methanol in the cylinder to cause a hydraulic lock when the piston comes up to top dead center on the compression stroke. In that case you'll bend a rod or crack a piston or some such. But even a mix so rich that it approaches 4:1 is not unheard of.
I set the 'E' fuel competition coupe/sedan record, and then re-set it twice more the same day, and the only change I made each time was to go up a couple of numbers between runs on the methanol jet. Then I ran out of jets, so, who knows? Maybe I could have gone faster yet! :)
KS
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Does anyone remember Edelbrocks "vari-jection" from the past? I ran one on a 66 428 engine and never heard a knock. They recommended using windshield washer fluid in the reservoir.It was on that truck for over 2 years then sold the truck, Simple and effective.
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There were systems long before Edelbrock's -and yes, I do remember it. The Olds Jetfire turbo from I think around 1962 used what they called Rocket Fluid, which was, for the most part, windshield washer fluid to quell detonation.
Snow is probably one of the industry leaders in water/methanol injection for both carbureted naturally aspirated to injected boosted applications.
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I have a Snow Performance kit on a supercharged 302 mustang. Best money I ever spent. It makes the overall fuel curve rich, and you lean out the Gasoline. I can run 15 PSI boost and still 38 degrees ignition advance. Actual power gain over race fuel just using pump 93.
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I have been wondering about this for a few years so now I will ask the experts.
I was wondering what effect good or bad it would have on a higher compression non boosted street engine.
I would like to run 91 octane as that is all I can get around here without going to race gas.
If it would run good and not hurt my engine I would run the Snow unit.
Thanks
Greg
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I was wondering what effect good or bad it would have on a higher compression non boosted street engine.
I have heard of people running methanol/water in non-boosted applications with good results. The engine doesn't know if it is boosted or not. It just knows if the cylinder pressure and temperature are too high for the fuel's octane. That could be because of boost or mechanical compression ratio, or other things.
JMO,
paulie
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Water injection systems were VERY common in the '60s and '70s on naturally aspirated engines. You wouldn't believe how common it was for guys to be running 12:1 pistons on the street. And, yes, 3/4 race cams, dual quads, tunnel rams, Thrush mufflers (or Purple Hornies) and chrome everywhere.
It helps to understand how a water/methanol (or just plain old denatured alcohol) works. The one obvious side is where the mix is injected into the intake manifold. We know this helps to cool the intake air through both the latent heat of evaporation, which means that heat in the system is being removed just through the chemical process of evaporation of the liquid, and the presence of a cooler liquid medium that helps to absorb heat even though it has not evaporated. The other way the mixture helps is in the combustion chamber. Here, the same evaporation process is taking place but the affect is more dramatic. As the piston is rising, whatever is in the combusion chamber is being squeezed. As you know, when you compress gasses, it raises the temperature. This heat vaporizes the liquids in the combustion chamber and in that process, latent heat is being removed making the fuel/air mixture less susceptible to abnormal combustion.
Water injection has never gone away. It's just that the circumstances that brought them to prominence kind of passed by when we knuckleheads quit building 12:1 street engines. The systems out there, like the Snow system, got new life with the advent to boosted systems. But they do make systems for naturally aspirated carbureted engines and they work just the same today as they did 70 years ago.
Here's a useless fact: B-52 bombers use water injection to increase engine thrust. Those eight turbofans hanging off the wings are what are called volume engines, meaning the thrust is based upon the volume of air going through the engine. And just if you were interested, a Turbojet is a pressure engine, meaning thrust is a consequence of gas pressure. One way to increase volume for the Turbofan is to use a liquid that vaporizes. In this case, the B-52 uses distilled water. It's injected into the engine and the volume difference between an atomized liquid and a vapor is roughtly 600 times. So you get more thrust in the process of the rapidly expanding vapor.
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Water injection systems were VERY common in the '60s and '70s on naturally aspirated engines. You wouldn't believe how common it was for guys to be running 12:1 pistons on the street. And, yes, 3/4 race cams, dual quads, tunnel rams, Thrush mufflers (or Purple Hornies) and chrome everywhere.
It helps to understand how a water/methanol (or just plain old denatured alcohol) works. The one obvious side is where the mix is injected into the intake manifold. We know this helps to cool the intake air through both the latent heat of evaporation, which means that heat in the system is being removed just through the chemical process of evaporation of the liquid, and the presence of a cooler liquid medium that helps to absorb heat even though it has not evaporated. The other way the mixture helps is in the combustion chamber. Here, the same evaporation process is taking place but the affect is more dramatic. As the piston is rising, whatever is in the combusion chamber is being squeezed. As you know, when you compress gasses, it raises the temperature. This heat vaporizes the liquids in the combustion chamber and in that process, latent heat is being removed making the fuel/air mixture less susceptible to abnormal combustion.
Water injection has never gone away. It's just that the circumstances that brought them to prominence kind of passed by when we knuckleheads quit building 12:1 street engines. The systems out there, like the Snow system, got new life with the advent to boosted systems. But they do make systems for naturally aspirated carbureted engines and they work just the same today as they did 70 years ago.
Here's a useless fact: B-52 bombers use water injection to increase engine thrust. Those eight turbofans hanging off the wings are what are called volume engines, meaning the thrust is based upon the volume of air going through the engine. And just if you were interested, a Turbojet is a pressure engine, meaning thrust is a consequence of gas pressure. One way to increase volume for the Turbofan is to use a liquid that vaporizes. In this case, the B-52 uses distilled water. It's injected into the engine and the volume difference between an atomized liquid and a vapor is roughtly 600 times. So you get more thrust in the process of the rapidly expanding vapor.
Wasn't the B-52 engine's water injection used only on takeoff? I thought it was after watching long ago a whole squadron of BUFF's taking off from a North Dakota AF base.
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Yes, just for takeoff. Loaded with weapons and fuel, it was on the porky side.
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The Germans were using methanol injection in their airplane engines back in the 30's. It was controlled by the pilot, and could only be used for a short period of time, but it provided a definite power boost. As others have noted, I remember back in the 70's, when water/alcohol injection kits came out, to compensate for lower octane gasoline.
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By the end of WWII the Germans had M/W systems that could be used continuously for around 30 minutes. Of course that dictates a fairly big tank for the M/W. They needed it because their gas had much lower octane than ours. It is hard to make high quality fuel when your refineries are getting bombed pretty much weekly.
There was a period mid-war, maybe 1943 and 1944 when their planes (engines) were getting their ass kicked because they couldn't run as much boost and they hadn't implemented a way to compensate yet. By wars end, there was parity again, but of course too late. Of course there are lots of other factors, too. The guy who designed the two stage supercharger for the Merlin was knighted, with good reason. The Merlin engine itself wasn't overly impressive in my opinion, but the two stage blower was a work of art. Combine that with good fuel and you can do amazing things.
I don't know if the numbers translate directly, but they had two main grades of fuel, something like 87 and 100 octane. By the end of the war we had something like 120 and even 150 octane, allowing more manifold pressure.
An on top of that we could inject M/W, too. I don't think we used nitrous oxide? But the Germans did.
Aero piston engines are very interesting.
paulie
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I am installing a Snow Performance system on my newest 671 Blown 390 Combo ( higher compression than the norm rule for street pump gas combo , as its 10.25-1 ) hope to be running at the 2020 FE Race and reunion this year , also going back to my C-6 combo for now will let you all know how it works , The new Meth systems are a quantum leap in technology compared to the water injection systems that were previously available , they are a far cry from a windshield washer pump and a nozzle :-)
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I ran a Snow water injection set-up on my blown 454 FE for quite a long time. It worked fine and the results were exactly as advertised. I bought the Snow "Boost Juice" but you could buy methanol and demineralized water and mix your own for cheaper. The only gripe I had about the Snow system is that the controller is quite small and getting my fat fingers to work it was difficult. You can ramp in the amount and boost level that the water/meth comes in with the Snow system.
In my research on the water/meth systems I came across some interesting data. It seems the 50/50 mixture was decided upon by current kit manufacturers not because it gives the best results. At 50/50 the the mixture is supposedly not flammable and reduces liability of selling the kits. Alcohols burn with an invisible flame and fires are highly discouraged. Many use straight methanol, but most serious users reportedly are using a 70/30 meth/water mix.
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I am installing a Snow Performance system on my newest 671 Blown 390 Combo ( higher compression than the norm rule for street pump gas combo , as its 10.25-1 ) hope to be running at the 2020 FE Race and reunion this year , also going back to my C-6 combo for now will let you all know how it works , The new Meth systems are a quantum leap in technology compared to the water injection systems that were previously available , they are a far cry from a windshield washer pump and a nozzle :-)
Where do you inject the M/W in a roots blower application? Sounds like it is going to run hard.
paulie
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I am looking to buy a system for My supercharged Cammer , I think I will inject in just under the Enderly hat, so it good to read about it hear wit someone that have done it, I drilled the intake for injectors so I can use the Hilborn plate for the meth system I think any way ?. Leny Mason
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Excess is just right for the cammer, Leny.
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I would think you would want the M/W injected after the blower. But I don't know. I certainly don't water going through my blower. I think it eventually causes pitting on the rotors and case? Plus, it seems like adding the "coolant" after the charge is heated would be more beneficial than before? Again, I don't know for sure.
paulie
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On my Snow kit the water/meth was injected in plates, similar to nitrous plates, under the carbs. I ran it for 3-4 years with no harmful effects to my blower and the fellow who has the Mustang now has run it for a couple more years. The way I had mine set up was that the system started injecting a small amount at 5 lbs. of boost and was "all in" at 8 lbs. so it's not as though the blower is seeing the Boost Juice except when your leaning on it.
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On my Snow kit the water/meth was injected in plates, similar to nitrous plates, under the carbs. I ran it for 3-4 years with no harmful effects to my blower and the fellow who has the Mustang now has run it for a couple more years. The way I had mine set up was that the system started injecting a small amount at 5 lbs. of boost and was "all in" at 8 lbs. so it's not as though the blower is seeing the Boost Juice except when your leaning on it.
Good to know. Thanks. Maybe I was thinking of injecting M/W into the inlet of a centrifugal blower causing issues? Or maybe it is not an issue at all.
paulie
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It can potentially cause an issue (erosion of blade tips) in a turbo if injected pre compressor wheel, but is still done quite a bit. I don't think there is any issue on a blower.
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Faron have you had that bad boy at the track before. With the blower.
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I put the Blower on in 1987 rather than try and find a 427 block , it was raced from then till 2010 best time of 10.56@133.56 in full pa street trim 10.33@134.87 in race trim .this is a new combo , more cam better heads ( Blair Patrick Prepped ) 10.25-1 compression oh and the car weighs 3675 with me in it
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Thats sweet and impressive
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It can potentially cause an issue (erosion of blade tips) in a turbo if injected pre compressor wheel, but is still done quite a bit. I don't think there is any issue on a blower.
With the turbos, I've witnessed failures of the impeller from shedding vanes to complete loss experienced when injecting chilling fluids into the compressors. :o
In the case of GMC blowers, the concern would be if the cooling effect to the rotors caused enough distortion to effect the available clearances in either the rotor to rotor, or the rotor to case. This would only be ascertained upon inspection, as the sum of clearances and fluid varies in each instance.
Scott.
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A Roots Blower has no problem with water Meth injected from above , a centrifugal or turbo needs to have the nozzle After the impellers
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Doesn't the 71 series superchargers, push the fuel to the rear of the manifold?