straight water vs Methanol or a Methanol mixture

[boostm3]

Its been awhile since Ive posted, but Im still curious about whether its better to use straight water, a mixture, or straight methanol.

The engineers over at Aquamist push very strongly the idea that water is a much better antidetonant in the chamber than is alcohol. There belief in alcohol only goes so far as that it prevents freezing in winter! They firmly believe that water by itself is the best agent to use to prevent knock.

Who am I to argue with the experts over there. Yet it seems to me that there are more components to the efficay of water injeciton than just suppressing knock in the chamber. For instance, in my setup, I run 11 psi boost on a vortech blower, with no intercooler, on an engine with a SR of 10.5:1. I believe that alcohol in the spray will cool the intake charge before it ever gets to the chamber better than straight water. But my overall goal is to prevent detonation. Yes, its nice to cool the charge too. And my 50/50 mixture was able to produce IAT sensor results on the dyno within 15 degrees of the INtercooled boys with a similar setup. matter of fact, whereas I was runnint 11 psi, they were running but 8 psi. So, its very possible were they making as much boost as I, that our intake air temp readings would be the same. Kudos to water/methanol injection, with the Aquamist 1s system. By going to straight water, perhaps I loose 5 to 10 degrees at the IAT sensor. But if doing so can deliver the ultimate in knock suppression, than going to straight water is the smart thing to do. Right now, Im in between, running about 18% alcohol.

But nowhere, but here, have I heard that straight alcohol is as effective as water at preventing detonation. What do guys over here know that Aquamist doesnt?

 

[Razor]

I guess there are a couple other factors. On is that methanol burns..and burns clean. It has a high octane number.
Also spraying methanol helps clean out oil contamination of your intake..those that use a PCV. Water and oil dont mix.

Personally I have been able to run more boost on staright methanol than on straight water, My car will run 20 PSI on straight water..and 26 PSI on methanol same knock retard readings. And run in between those numbers. Never got into mixing since methanol at 2.50 a gallon..pretty cheap as is.

The only real way is using a detonation detector(knock guage) and start your own experimenting. You should have results pretty fast..every car and combo is different. I do understand aquamists feelings and opinions, just straight has worked better/more consistent with me.

 

[boostm3]

All I can add is that the engineers at Aquamist persist in maintaining strongly that Water is a far better anti detonant than is alcohol. Something about heat latency, etc, etc... If anybody would know about this, its them. On their site, they say:

"10. What is the maximum alcohol/ water ratio I should use?
No more than 50%, otherwise you will increase the cylinder temperature rather than reducing it. Beyond that ratio, onset of detonation is more likely. Methanol freezes at -96 deg. C, 50% mixture will stop the mixture from freezing at around -40 deg.C. "

But theyve given many other reasons in different locations why they dont like a predominant alky mixture.

 

[Razor]

You asked and got my response..play with water..maybe on the Beemer its better..dunno.. I havent seen a car run into the 11's on water alone.

Plenty of TR's running 11's on methanol.

But why would aquamist recommend a liquid that theyre systems are incompatible with

Its not alkymist but aquamist

 

[boostm3]

>>You asked and got my response<<

Thats fine...what I was hoping for is some reasoning as to why you buick guys are seeing better results with alky, when the scientific theorizing regarding heat latency, etc, all points to water as being the superior fluid to use for knock prevention.

>>But why would aquamist recommend a liquid that theyre systems are incompatible with <<

Why would Aquamist design equipment to be used with anything less than the best detonant

 

[Freedster]

They're probably right to a certain extent

If you think about it, water probably has a damn near infinite octane rating. It also has a very high specific heat, so it does probably cool combustion chambers about as well as anything. The government also did some extensive research on this during WWII for supercharged piston aircraft:

http://naca.larc.nasa.gov/reports/1943/naca-report-756/

That having been said, I wouldn't run straight water myself. I'm no expert at all, I don't have a system installed, and I'm no engineer either, but I think the anecdotal evidence really points to adding alky to the mix.

- Freed

 

[boostm3]

>>If you think about it, water probably has a damn near infinite octane rating<<

Youre making many of the points those who feel water is the superior product to use are making.

>>That having been said, I wouldn't run straight water myself<<

So, after having made the case for water, how do you arrive at this?!! Those who wind up going with a mixture usually use the alky to help the water evaporate at a lower temperature. But if water takes more heat with it when it evaporates either in the intake tubing or in the chamber, then why use the alky at all.

Even Im not running straight water..Matter of fact, up to a few days ago, I was running 50% methanol. But Im just far from convinced straight alky is nearly as effective as a mixture is. And Im far from convinced that a mixture is as effective as straight water. We have plenty of evidence as to why water is the more effective anti detonant. But so far, all Ive seen about alky being better is that well, hey, the guys here seem to like it! Sorry, thats not good enough for me, and it shouldnt be good enough for you either.

BTW, that article clearly shows the effectiveness of water as an antidetonant. What we need to see are some technical evidence explaining why straight alcohol can be as effective. If an engine is running on the lean side, then its possible an engine will show a power increase under the influence of straight alky.. But it would be a mistake to conclude it's because of its superior anti detonant properties. All youd be seeing is that in increase in richness if an engine is lean will increase power. I dont think thats news to anybody here.

 

[Freedster]

Originally posted by boostm3
>>If you think about it, water probably has a damn near infinite octane rating<<

Youre making many of the points those who feel water is the superior product to use are making.

>>That having been said, I wouldn't run straight water myself<<

So, after having made the case for water, how do you arrive at this?!! Those who wind up going with a mixture usually use the alky to help the water evaporate at a lower temperature. But if water takes more heat with it when it evaporates either in the intake tubing or in the chamber, then why use the alky at all.

Even Im not running straight water..Matter of fact, up to a few days ago, I was running 50% methanol. But Im just far from convinced straight alky is nearly as effective as a mixture is. And Im far from convinced that a mixture is as effective as straight water. We have plenty of evidence as to why water is the more effective anti detonant. But so far, all Ive seen about alky being better is that well, hey, the guys here seem to like it! Sorry, thats not good enough for me, and it shouldnt be good enough for you either.

BTW, that article clearly shows the effectiveness of water as an antidetonant. What we need to see are some technical evidence explaining why straight alcohol can be as effective. If an engine is running on the lean side, then its possible an engine will show a power increase under the influence of straight alky.. But it would be a mistake to conclude it's because of its superior anti detonant properties. All youd be seeing is that in increase in richness if an engine is lean will increase power. I dont think thats news to anybody here.

I probably wouldn't run straight alcohol either.

I think that the combination of alcohol and water would be the best thing. When you are running more boost, you need more than just a cooled intake charge, you also need more fuel or things will get too hot. I think that the alcohol provides that fuel while cooling the mix some, and additional water cools off the intake charge more.

I've also seen what getting water in the fuel lines on an injected engine will do to it firsthand. (Yes, I know, this system isn't going through the fuel system, yadda, yadda.) The engine bogged down horribly and was undriveable and eventually the plugs became water fouled and the car was undriveable. (Thank god it never hydrolocked!) Shooting straight water into the intake just worries me because of this experience in my past. Maybe it made me superstitious.

Then again, the smart thing for me to do would be to just shut up until I get a system installed and try some different mixes in it, right?

Thanks for the discussion. Nice article, eh?

- Freed

 

[Freedster]

OK, I did a little digging...

Apparently, Aquamist even seems to think a 50/50 mix is great. From their website:

http://www.aquamist.co.uk/dc/coollinks3/index/street/smdex/maserati/maserati.html

from the last paragraph:

"....There was no boost loss, no engine overheat, no loss of oil pressure, just the muted bellowing of a Maser in full cry, gargling down its 50/50 water/alky mix, courtesy of Aquamist!!! I am utterly delighted with it."

- Freed

 

[boostm3]

>>Apparently, Aquamist even seems to think a 50/50 mix is great<<

Trust me, they dont think its 'great'..I have over 300 pieces of correspondence from a chief engineer there, and the ONLY reason they recommend its use at all is to prevent freezing in the winter! As a matter of fact, they quote the engineer I ve done all my corresponding with; Richard Lamb!

Im not such a hard liner in that I experiment variously from about 15% right up to 50% methanol. What Im questioning more than anything else is the use of 100% alky as an effective anti detonant when compared to water or water mixtures up to 50%.

 

[Razor]

Originally posted by boostm3

Why would Aquamist design equipment to be used with anything less than the best detonant

Guess I know why Buick guys dont run aquamist stuff

Try it for yourself and see, that way there will be no bias based on ADVERTISING BS . I dont have to convince you..my runs at 28 PSI on straight 93 octane fuel are proof enough for me.

See my tail lights at the track Water Boy

 

[boostm3]

>>my runs at 28 PSI on straight 93 octane fuel are proof enough for me.<<

Uh, I think we need a little more info. Like, how big is your engine, whats your static compression ratio, how much hp did it make stock, vs how much are you making now, etc, etc...

I think youll find relatively few people who are able to run 11 psi on a 10.5 CR engine

 

[Red Regal T]

I don't care what the "experts" say.......all you have to do is time the car with different mixtures. Proof will be in the pudding. When some mixture goes faster, you'll have more questions for the experts. I don't know what exactly will work for you.

Oh Razor? He's bad. 231 cubic inches of rompin', stompin, stock turbo Buick motor, never opened, injecting some methanol.

 

[Razor]

Stock on my car is 250 HP on a 9 to 1 motor running 16.5 PSI of boost. According to GM lit.

Last Time I dynoed it Nov 2002 it ran 415 RWHP and 608.5 TQ at 23 PSI boost. 1/4 mile trap speed that week was 114. Since then the car has gone under 119 MPH at 26-27 PSI of boost on a completely unopened stock motor..only upgrades to motor are turbo and injectors. 119 on my car translates to over 450 RWHP. Still has the plastic timing chain, intercooler screen, stock unported anything, heads/intake have never been off the car.

I dont play with water..even tho some scientist may say its better..it just hasnt been for me...yet.

tune tune tune..

10.5 cr..ouch..contact Dinan and get some 8:1 pistons..then you can make some real power..but like all beemers with power, half shafts will be your demise.. I know Tommy with the turbo M3 here in Tampa. He ran like 11.8 at 118.7..but was like twice a month at the dealer with suspension carnage. $$$$$

 

[TurboSy]

Originally posted by boostm3
>>You asked and got my response<<

Thats fine...what I was hoping for is some reasoning as to why you buick guys are seeing better results with alky, when the scientific theorizing regarding heat latency, etc, all points to water as being the superior fluid to use for knock prevention.

>>But why would aquamist recommend a liquid that theyre systems are incompatible with <<

Why would Aquamist design equipment to be used with anything less than the best detonant

Water might be a superior fluid for knock prevention, but were missing a few variables.

First how much water can you burn before the ignition starts to break up? I'm positive I can burn at least 2-3 times more methanol without putting out the flame. Even if water twice as effective ounce for ounce, you'll still have better overall knock prevention with straight methanol Vs straight water because you can burn so much more.

Next you need to consider what makes more power, introducing say 20% more fuel and burning it efficiently will increase power, increasing 20% water will most likely decrease power, until you turn up the boost/timing, which can also be done with methanol to make even more power.

I've personally had great success with methanol, and if I could do it with water I'd be the first in line.

 

[boostm3]

>>Next you need to consider what makes more power, introducing say 20% more fuel and burning it efficiently will increase power<<

Unless youre rich already....there IS such a thing as being too rich.....'Lean is Mean'...one of the reasons water injection works well is that it lets you run somewhat leaner; tuners frequently increase enrichment to boggy levels becuase they use fuel as a chamber coolant in the absence of water injection. With water injection, theres no more need to use gasoline for this purpose, so you can scale back to the enrichment level which is optimal, with all cooling duties handed off to the water injection.

Razor, thats one awesome beast you have there...really, quite impressive. The best Ive dynoed on mine with my 11 psi boost is 330 SAE rwhp, which on my car, is around 400 crank hp which on a 10.5 CR engine isnt bad either The car, stock, usually dynoes around 205 rwhp. Problem with reducing the compression ratio on this car is that, being a street car, unboosted performance would really suck if I did that, and as a daily driver, I need to maintain its driveability. If it were a dedicated dragster, well, that would be an entirely different story

>>10.5 cr..ouch..contact Dinan and get some 8:1 pistons<<

Thats one of the issues. Dinan is very hard to deal with. For instance, my Dinan exhaust which I bought with their SC kit, making it a 'stage II', and delivering 16 extra hp according to them, developed a nasty resonance at 4k rpms. It was at the end of the warranty period but still covered, but when I asked for relief, they told me that because I was using water injection, and upped the boost by 3 psi, they would have to deny coverage on the exhaust! I explained to them that the winjection made my car run cooler than their stock setup at 8 psi without winjection, but it made no difference. Point is, they are very stubborn, and very rigid. They do NOT offer any mods to their SC kit by way of compression changing, or anything else. OF course I could go elsewhere for them, but I believe as I indicated, being a daily driver, I didnt want to compromise off boost driveability.

Active Autowerkes (activeautowerke.com) in Miami, makes the best turbo setups for my car, and theyve done some amazingly powerful kits that work on my model. But , back to the issue. I think that because I dont have an intercooler, the duty I need my winjection system to perform is a little different from what you guys are trying to get out of your systems. My prime concern is heat in the chamber, and resulting detonation. I think a water/methanol mixture is the best answer for me, given my setup. I think your goals are a little different, with your vastly different setups. But Ive even spoken to members of your community who believe that a methanol mix gives them the best results. Others swear by 100% methanol. Different goals; different results. Its all good

 

[KillrV6]

pardon me for side busting in on this thread, as i do not have any form of alky or watter injection.

is the watter burned in the combustion chamber?
sinch the anser to that question is no, , that meens it turns into steam right?

im just guessing here, but isnt any thing that goes into the chamber that does not burn before it goes out just wasted space? wouldnt it make more power to burn more fuel? if you wanted to run leaner there are pleanty of ways to do that on a turbo car right?

once again, i dont know for sure, im just throwing stuff out here.

 

[Freedster]

Originally posted by KillrV6


im just guessing here, but isnt any thing that goes into the chamber that does not burn before it goes out just wasted space?

I was kind of thinking this myself, and then I read this page:

http://www.drwtransmission.com/gnpage.htm

The pertinent info is at the bottom. Quoting:

The specific energy of methanol is slightly higher than gasoline. The SE of a fuel is obtained by dividing the fuel's heating value by its stoichiometric air-fuel ratio. This represents the amount of heat energy a fuel can deliver for a given amount of air drawn into the engine. In other words, how much heat energy a given amount of fuel can deliver when it burns in exactly as much air as necessary. SE ratio is a useful measure to compare fuels. It represents the ratio of the SE of a sample fuel to that of a reference fuel, usually iso-octane, which is similar to commercially available gasoline. SE of gasoline is 2.9, methanol is 3.08. The heat of vaporization (cooling effect) of methanol can significantly increase charge density. This means you have a fuel with a higher SE than gasoline and more of it packed into the cylinder. The relationship between the volume of chemical reactants (the charge mixture prior to combustion) and the volume of chemical products of the combustion event (exhaust gases) is known as chemical expansion. The higher the ratio of products to reactants, the higher the combustion pressure and the higher the potential power output. Enriching air-fuel mixtures builds power until the added energy of the additional fuel is offset by the decreasing flammability. This is known as air-fuel flammability limits. Broad rich-flammability limits permit higher potential power. Methanol is typically run at an air-fuel ratio of 4 to 1 in performance applications. I can tell you from experience methanol has a very rich-flammability limit. Liquids consume energy as they boil, providing a cooling effect (Heat of Vaporization). This effect can significantly increase charge density, increasing the mass of air drawn into an engine. Fuels which consume a lot of heat to vaporize provide significant power benefits by effectively increasing engine volumetric efficiency. As stated above, the oxygen requirement of methanol is very low which means more fuel can be delivered to the combustion chamber for burning. With methanol, higher compression ratios can be used because of the octane and heat of vaporization value of the fuel. We all know that high compression engines make more power because they are more efficient at getting energy from the air-fuel charge mixture. Because of methanol's high SE, it's lower heating value is more than offset by the favorable stoichiometric air-fuel ratio. At stoichiometric, methanol makes slightly more power than gasoline. However, methanol makes maximum power at a 4.0:1 air-fuel ratio, some 30 percent richer than the 6.45:1 stoichiometric air-fuel ratio, a condition under which the SE is vastly better than that of gasoline, which makes maximum power at only 20 percent richer than stoichiometric. Methanol's SE advantages as a racing fuel are magnified by the cooling effect of its high heat of vaporization, which significantly chills the inlet charge, providing improved engine VE. The high chemical expansion value of the air-fuel charge means more mass traveling through the exhaust system. This higher exhaust mass will cause a given turbo to spool faster. I'm running a T-70 with a .96 A/R ratio housing and boost starts at 2900 rpm. This is with an exhaust temp of only around 1200 degrees F. For a racing fuel that makes for a more efficient running engine (for racing purpose), pure methanol is the way to go.

Methanol has what's called a polar hydroxyl group in its chemical makeup. In essence methanol is a partially oxidized hydrocarbon. It is for this reason that methanol does not take as much air to burn efficiently, as compared to gasoline. Due to the presence of oxygen in the fuel, less oxygen is required per unit weight of fuel, meaning a given amount of air drawn into an engine can burn more fuel. Nitrous oxide (commonly used as a power adder when burning gasoline) adds oxygen to the charge which allows (demands) more fuel to be added for the following reasons: 1) more power can be produced because of the additional fuel that can now be burned, 2) The cooling effect makes for a denser charge which again demands more fuel to maintain a correct A/F ratio, 3) if you don't add the extra fuel you'll lose a motor (massive lean out). You can start to see a pattern here. The way to make horsepower is not by how much air or oxygen you can stuff into a motor, it's how much fuel you can burn efficiently with a given amount of air or oxygen! If you can displace the air intake that you must take in with gasoline and replace it with fuel and still burn it efficiently, then you start to see the advantage of making methanol that fuel. The turbo does not need to be as big because the demand for air intake was just cut dramatically. Not as much boost needs to be used, so you can run your turbo at a boost level that the turbo is more efficient at, and you make more power because of the SE (specific energy) of methanol.

I'm a believer in shooting straight alky now. What he says makes sense. Sounds like water is a waste of space.

- Freed

 

[boostm3]

>>I'm a believer in shooting straight alky now. What he says makes sense. Sounds like water is a waste of space.<<

Thats only because you guys keep approaching this from a fuel enrichment standpoint. But thats NOT the purpose of water injection. The dual purpose of water injection is to Cool the Intake charge AND to smoothen out the burn in the chamber. Unlike intercoolers, water injection will NOT make power on its own. IF thats your frame of reference, then of course youre not going to understand its purpose. You will get some fuel enrichment value out of straight methanol, or even a mix. But the purpose of the water is to increase the 'effective' octane in the chamber. It behaves very similarly to high octane fuel, in that it prevents uneven combustion, and therefore, makes for an environment very unfriendly to any knock. But, as someone pointed out, it does not burn (has infinite octane if you like), and can be viewed as wasted space from a fuel enrichment standpoint. But...The proper way to use water injection is that in its presence, large amounts of increased boost and increased timing may exist. So, with water injection, you can use timing and increased boost, and thats how to make power with water injection. Im my category, for instance, most supercharger kits dont come with intercoolers and therefore can only make 6 or 7 psi safely. But, under the influence of water injection, ive bumped that to 11 psi, on this 10.5 cr engine, and knock is never an issue. Im also making 30 to 50 extra rwhp as a result Thats how we use water injection. Forget about fueling...Thats not what its all about. There are plenty of places to learn more, but the best place to start is http://www.aquamist.co.uk/

>>The specific energy of methanol is slightly higher than gasoline<<

But the calorific value is half If I use 50% methanol,

For example, 50% methanol from a .7mm jet equates to 140cc of methanol per minute, for 350HP requires approximately 2 litre of fuel, the methanol ratio to fuel is 140cc/1800cc or 8%

Incidentally, heres the size of the enrichment I can get with my current .7 mm nozzle:

If using a .7mm nozzle, we flow 280cc of fluid = 140cc methanol (50/50). At 1/2 calorific value of gas = ~70 cc methanol = ~4% more fuel. With an a/f ratio of 13.2:1, that equals 23040/1875 = 12.29:1 . Thats not a bad increase in enrichment But...by the same token, it can also be shown that while enrichment is being enhanced a little, youre also not getting as much cooling in the chamber.

The Big question is, are you deriving more benefit from the enriched mixture, and slightly hotter chamber, or are you deriving more benefit from the same mixture as before, but a colder chamber. And I suscpect the answer to that one will be different for each application

 

[KillrV6]

i think your right M3 guy, about the fact that it will be diffrent for each aplication. i think that maby the buick guys get more of a benafit out of the straight alky because the combustion chamber design of the LC2 is dated. my friends can run 20 psi on their audi's on striaght 91 octane because of the advanced combustion chambers on those things.

maby the buick's combustion chamber is so dated that even if it was "cooler", it would not efficiently be able to handle as much boost. the best choice in this situation would be to deal with the heat and just enrich the fuel so that more boost could be used.

on a car w/ DOHC aluminum work of art heads where im sure now a days they calculate efficiency when they are designing the heads, and design them so that the only factor that is counterproductive is the heat of combustion, watter injection would work best.

does that sound right??