Howard Coleman

iTrader: (6)

it really is pretty simple.... comparing water to alcohol to a mix. all the work has been done, there really isn't any conjecture except in some people's minds. the physical properties differences dictate what each is going to do and not do for you and your motor.

each injectant based on it's properties has it's place. yes, if you are pursuing a particular objective one might be better than the other.

this thread is NOT a place to argue mine is better than yours. it is a place to get the facts and then move forward.

the primary principle of the AI Section is:

run water

run alcohol

run a mix.

but run something or fry your motor.

that said, i will be posting a physical properties comparison during the next week and hope it clears away lots of part truths that fly around out there in cyberspace.

howard coleman

BDC

Here's some links for reference:

http://www.engineeringtoolbox.com/sp...ids-d_151.html

http://www.engineeringtoolbox.com/me...ter-d_987.html

http://www.geistware.com/rcmodeling/...el_cooling.htm

http://www.distill.com/materialsafety/msds-eu.html

http://www.methanol.org/pdf/MethanolMSDS.pdf

Node

iTrader: (1)

what happened to next week?

ScuttleRX

From what I read on another thread, Howards write up on this is about 25 pages at the moment so hes busy doing some editing

afgmoto1978

iTrader: (6)

So what happened to this??

Barry Bordes

Barry

BDC

Great info. Where's the source documentation?

B

Howard Coleman

iTrader: (6)

apologies to all for the brief delay...

the primary reason i didn't follow thru was about the time i started the thread the AI wars were escalating and i just decided to let things cool a bit rather than stir the injectant pot.

ideally this thread should not be an either or (water or alcohol) but a resource as to what makes each injectant a bit different.

both have a legitimate place in the AI space.

that said, just a couple of comments...

you really see differing numbers on alcohol's octane. one of the problems is that octane is rated at a specific temperature. alcohol cools so much that there is no way it can be rated at that temperature so we get guesses.

i will say this... it has been my experience thru lots of road testing and 3 dyno sessions that the more alcohol the better. i will be shortly moving from 1200 CC/Min to 1600 CC/Min at peak torque/peak boost.

one of the more interesting considerations is the autoignition temperature of alcohol... to be clear, autoignition is simply the temp where a substance starts burning.

this is highly relevant w the rotary relative to preignition/knock.

gasoline, including racegas, auto-ignites at 660 degrees F.

alcohol, (methanol, ethanol and isopropyl) ignite at 858 degrees F!

that's alot of additional protection against bad things...

i'll be back with more.

any people feel free to add here and that includes the waterites.

hc

Howard Coleman

iTrader: (6)

i was checking out Boostcreeps.com and stumbled on a thread talking about the hi value of low IATs (intake air temperatures)...

http://www.boostcreeps.com/phpBB/viewtopic.php?t=501

"I was tuning a car on the dyno that had high IATs. We sprayed the IC with some nitrous to cool it down, and this dropped the temp 10degF, and the car picked up 14whp!! Same timing, same AF, same boost ,etc (replete with AEM logs to substantiate this claim). This was on a car making mid-high 500s. Quite a significant bump! And this car had about another 30degF left to go before the temps were 'ideal' (i.e. 10degF above ambient)... so in theory it could pick up 45whp from just a better FMIC! Quite significant. So IAT reduction might be a worthwhile point on those of us running undersized FMICs. While the race gas can keep the detonation at bay, the gains from increased air density seem quite significant."

of course we know that the primary deal w lower IATs is more oxygen molecules per volume. and when you are talking oxygen nothing beats alcohol, or methanol specifically.

meth is 49% oxygen by weight
ethanol is 34% oxygen by weight.
gasoline is zero% oxygen.

as to cooling:

meth is 1.154 MJ/Kg
eth is .913
gasoline is .297


Meth is the winner.... lots of oxygen and lots of cooling.

hc

DarkKnightFC

Very similar to that^^^, I read an article where someone was using a dual loop intercooler sprayer that looked like a figure 8 on thier drag civic and it picked up 60 horses. Of course they were also spraying nitrous onto the core. I'll see if I can find it.


EDIT- Here it is http://www.hondatuningmagazine.com/t...est/index.html

Barry Bordes

We seem to have missed the comparison to water.
Taken from engineeringtoolbox http://www.engineeringtoolbox.com/

Product Latent Heat of Evaporation
(kJ/kg) (Btu/lb)
Acetone 518 223
Alcohol 896 385
Alcohol, ethyl (ethanol) 846 364
Alcohol, methyl (methanol) 1100 473
Alcohol, propyl 779 340
Benzene 390 168
Heptane 318 137
Hexane 365 157
Kerosene 251 108
Propane 428 184
Toluene 351 151
Water 2257 970

Barry

sonick117x

i hate to bring this thread back from a few months but it seems that barry is showing the latent heat for vaporization of water is twice that of methanol and second highest enthalpy to ammonia.. which is due to hydrogen bonding.. and i understand that the more oxygen the better for keeping autoignition down but im just wondering the results of water compared to alcohol numbers-wise.. if anyone can show some quantifiable data that would be much appreciated thank you

edit: i realize the ammonia thing isnt in barrys post i was just throwing it out there

ericgrau

iTrader: (1)

I think we're missing the numbers for the specific heat of each fuel in both liquid and air form. I believe latent heat of vaporization numbers are measured at the boiling point, which can skew things if you're spraying a liquid below the boiling point. Then you need to figure out how much energy it takes to heat it up to boiling first, based on the specific heat of the liquid and the change in temperature. And this all might vary with pressure too, I don't remember.

So what we really need is to calculate in then is X kJ of heat absorbed per kg of fuel when the air temperature right outside the intake is 70F, 80F, 90F, 100F, 110F and 120F. That would help provide the most direct comparison between the cooling properties of each. And it would be useful if you're looking to replace x grams of gasoline with y grams of water or with z grams of alcohol and need to get an estimate of what y or z should be. There may be other factors to consider as well, but this should be what matters in terms of preventing detonation.

ReZ311

iTrader: (4)

I always wanted to do a 50/50 mix of water and Methanol, but it's too time consuming for me to play chemist and get the mix right every time I fill up. Especially when you drive alot. Rather not worry about it and just use 100% Meth. It smells good too when you smoke the car behind you. *Burning Eyes!*

clint999

Very similar to that^^^, I read an article where someone was using a dual loop intercooler sprayer that looked like a figure 8 on thier drag civic and it picked up 60 horses. Of course they were also spraying nitrous onto the core. I'll see if I can find it.


EDIT- Here it is http://www.hondatuningmagazine.com/t...est/index.html

bumpstart

OK, my little contribution of what i have managed to glean elsewhere


i fill my rx7 with straight propane
despite the slight BTU losses in volume to blended LPG and petrol
its octane is almost unbeatable, its pound for pound, kilo for kilo comparable in energy to petrol
- and its pump quality/purity assured


-this is an amalgam from my other posts elsewhere-


footnote --

RON or MON or AKI?

in the US ( AKI ) and aus/Europe ( RON ) , different methods are used

what is US 87 octane ( AKI ) is European 91 ( RON )
or aussie normal unleaded
is actually RON 91, 86.75 AKI and 82.5 MON

and conversely ,,
what we in australia call PULP
RON 95 , AKI 91 , MON 85

and PULP 98
RON 98 , AKI 94, MON 88

and blended LPG is
RON 100 , AKI around 97, MON 92
MINIMUM
STILL SLIGHTLY BETTER THAN THE BEST PULP
even at 50% butane blended into 50% propane

and propane is
RON 115 , AKI 110, MON 103
and 91,547 BTUs versus 116,000 BTUs per gallon for gasoline/petroleum
-Methanol contains only 57,000 BTUs per gallon, which is half that of gasoline
( volume comparison)

But on a pound per pound basis, propane delivers almost the same energy as gasoline (21,591 BTUs)
( mass basis )




AKI - numbers ( averaged RON and MON )

hexadecane < -30
n-octane -10
n-heptane 0
diesel fuel 15–25
2-methylheptane 23
n-hexane 25
2-methylhexane 44
hydrogen* RON > 130; MON very low[5]
1-heptene 60
n-pentane 62
1-pentene 84
n-butanol 87
E10 gasoline 87–93
n-butane 91
t-butanol 97
cyclohexane 97
iso-octane 100
benzene 101
E85 gasoline 105
methane 107
ethane 108
propane 110
methanol 113
toluene 114
ethanol 116
xylene 117


here are all the fuel additive octanes -
where-
RON is the knock test at 600 rpm and 40 celcius air temps
MON is a test on same engine at 900 rpm and 150 celsius air temps
BP is the boiling point in celsius
AIT is auto ignition temperature
d is fuel density compared to 1 L/ 1 KG of pure water


--- you can see why in the past i was keen to use toluene and xylene and even acetone as minor fuel additives on drag day

bumpstart

these are the ricardo scale results
( anti pre-ignition index, as different from anti knock index )
where iso octane = 100, cyclo hexane = 0

-There is no direct correlation between antiknock ability and preignition
tendency

paraffins 50-100
benzene 26
toluene 93
xylene >100
cyclopentane 70
di-isobutylene 64
hexene-2 -26

Slides

Just have to reinforce a point I hate seeing.

With the alcohol fuels, "more oxygen means more power". No

Assuming after all fuel/AI injection the chamber fills with the same temperature and pressure charge, giving you the same mass of air (and free oxygen), the oxygen in the fuel doesn't add anything as it has already bonded and found a lower energy state, to fee it again to re-combust would require an energy input, and thanks to entropy, we go in ever decreasing circles there, any loss or gain going from a H-O-C bond in the fuel to a H-O-H or C-O-C will be very marginal so far as to be negligible as compared to all the free oxygen bonding with the hydrogen and carbon in the fuel.

So far as knock suppression/chamber temp control

All of the laws and relations are there for calculation of temp drop and heat absorption with different injectants you just have to take the time to do it (and to do it by hand with your thermo book from eng degree takes a while as you have to iterate and if it crosses those lovely vapour trasitions it is very hard to do with a basic spreadsheet or calculator as you can see with the humourous negative vaporisation temps you can get with 100% water using that not2fast calculator).

It does get complex with mixes crossing liquid/vapour temps and pressure changes, but to say simply that "all of the water turns to steam" in pre turbo so it can't act as knock suppressant is foolish, you have all the evidenced otherwise with your IAT's anyway, they are usually well below 100C, or realistially 107+C at 1bar+pressure so it is only ever in a very low portion vapour state, heaps of latent heat of vapourisation energy left to go, even if it did (if you were running staged series compressors at diesel tractor pull boost), once it has transitioned to steam it still has by far the best weight for weight thermal capacity (remembering that the fuels will all be in gaseous state at those temps too, with less thermal capacity) and when a charge is then compressed nearly 10 times in the engine (more in a diseasel [intentional misspelling]) there is plenty of capacity to absorb heat left there, if you work out the temp the air would "like" to reach under compression alone without injectants, let alone once combustion starts, you see that the potential (and real) temp reduction is massive as the thermal energy is balanced to the water.

I see water as by far the best solution in terms of acting as chamber cooling/knock suppressant for street cars no matter where it is injected pre or post turbo, I hope thinking about the vapor state portions is enough to make it very clear that heat absorbed on initial compression is still really SFA in terms of the complete vapourisation capacity of the water, let alone its specific heat past vapourisation, perhaps it is more obvious to people who grew up with the metric system thinking in the 0-100C range and the portion of energy to vapour state at you move through it.

What alcohol is far better at is bringing the temperature of the mix as it gets to the port to a lower temp, thanks to its much lower vapourisation temps and hence capacity to keep cooling charges near and below ambient temperatures (provided it has time before it gets there), to get that last 2-20% density increase (dependent on your setup, more for straight meth fuelled non intercooled setups), whereas water at those temps will just sit as fine droplets and relax happily some 15~20 degrees(c)+ above ambient from what people seem to be finding, I'm too lazy to have pulled my texts out as of yet and run hard numbers.

As i see it you really need a bit of both to absolutely optimise (i use real english spelling too) a setup (in terms of minimising absolute fluid use volumes for power produced, and other factors such as required compressor size/efficency as well), but depending on the compromises you are willing to make either can work very well on its own, as most of you have shown.

As I will be setting up a pump fueled car, and using it in areas where temp can go below freezing i am going to try a modest ethanol water mix, perhaps 15-20% ethanol by volume acting as much as antifreeze (in winter at least) for the reserve fluid as for what i hope will be some marginal pre compressor temp reduction of the intake air (so perhaps a % or two extra power at choke flow?? after ensuring ambient air to that point and minimum pressure drop across filters), if i am conscientious i will run a temp probe pre compressor to determine if a can see any difference between that and straight water at varying ambient temps. I hope to run several atomizers staged and run leaner than many people seem to advocate (pehaps .85 to .9 as opposed to "conventional" .7 lambda range), especially seeing as some of them have evidence of their own setups running close to stoic unaffected by mistake. :P

Slides

Has anyone considered the use of acetone as a full or parital component? It mixes with water & has a significantly lower flash point than methanol.

465 degree C auto ignition temp, similar to alcohols, heaps higher than straight hydrocarbon fuels.


Flash points

Methanol ~ +11 degrees celcius

Acetone ~ -18 degrees celcius

Tem120

iTrader: (5)

I know I read someone before about adding rubbing alchohol and it working ... but I cant find the thread now .. I'm using windshield wiper fluid and I was wondering if there was something I could use to add more alch then water . for better atomization doing the calculations isnt an issue for me .

and hah no I dont really plan to use rubbing alchohol .. unless it works doesi t really work? LOL

Just wanted to find out what kind of alch I can find and maybe locate a local place to find some pure alch to add to my windshield wiper fluid .

Islander

iTrader: (6)

I run the Boost Juice stuff.. Its pre-mixed meth/water. I think its 51/49%.

Tem120

iTrader: (5)

where do you find that?

and I already looked into the nearest place here that sells meth its not that far but closes when I get out of work , and to far for me to drive during my lunch break . so I'm just looking for alternatives LOL

Tem120

iTrader: (5)

Wiki being the awesome and reliable source of information that it is says that rubbing alchahol is 70-99 % ethonal or Isopropyl alcohol and its rated at 101 octane same as meth , so could I really using the right ratios add a mixture of rubbing alch , and windshield wiper fluid ? LOL

just discovered " denatured alcohol " ... sounds like fun... how is denatured alcohol , chemically different from meth. how does it affect the car in an adverse way ? why is it better to go out of your way and find meth from a racing shop compared to using the stuff you can buy from home depot?

Slides

Meth - single carbon atom
Eth - two carbon atoms (drinking alcohol, "denatured" alcohol)
Prop - three carbon atoms - Often used for sterilisation in medical applications

Don't discount acetone if you are looking for intake temp drops.