LS6427

iTrader: (2)

YES.....I'm new to all of this boost stuff. As soon as my *** gets back from the damn Middle East in 3-4 months......my Huron Speed A/C single turbo kit is going in.....
All I have to order is the S485 with 96 mm turbine, Bell 4.5" FMIC and Fuel system.......I have everything else needed for the complete install. It will be on my 390ci at 10.8:1 compression and full time E85 through a 4L80E. With everything else you see in my sig as supporting components.

-----I am told that Meth is sprayed after the MAF.

QUESTION:
If Meth is sprayed AFTER the MAF, why does it not mess up the air/fuel data that the MAF has figured out and sent to the PCM for the amount of fuel to spray?

The meth makes the air cooler after the MAF, which means its more dense.......but the data sent to the PCM by the MAF has read a different air density.

SO....wouldn't the best place to spray Meth at a position immediately after the air charge leaves the FMIC on the way to the MAF......?

Thanks......

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svslow

The stock ECU has no way of knowing what meth is. In most turbo application the MAF is eliminated and the PCM is tuned using a speed density algorithm. Spraying meth on a MAF would not work out very well I'm sure. So, if you are set on running a MAF and meth, do it after the MAF. And yes, adding meth will cause a richer A/F reading.

LS6427

iTrader: (2)

I plan on SD tune with my boosted set up.

BUT, the stock PCM reads air density via the MAF reading.

If meth is sprayed after the MAF then isn't the air density (((Because its cooler))) that is entering each cylinder MORE DENSE than what the PCM thinks it is, since that air never passed through the MAF?

Won't that change how the PCM treats the fuel delivery?

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ScottyBG

If you do a speed density tune the MAF is removed and the parameters in the ECM are set to fail it, set it to 0Hz. That way the computer calculates the airflow based upon engine RPM, MAP and IAT. The MAF numbers are no longer used to determine fueling. You will however need to modify your VE table to account for the additional fueling provided by your methanol injected. If your having your car tuned by a tuner they should have no trouble figuring this out for you. If they do get another tuner.

JakeFusion

iTrader: (7)

You can't run a MAF with that big of a turbo. It'll be done by 4psi on being able to read.

The better question is do you spray meth (and it has a shitload of octane in it since it's alcohol) before or after the IAT so you know the temp of the charge going into the motor... But with E85 you don't need meth. You already are using alcohol.

SethU

If you're planning to be E85 100% of the time you won't need meth or an intercooler.

However, to answer your question, even though you'll likely not be using a MAF anyway... As the air charge cools, it shrinks slightly. As you said, it's more dense. Being an open circuit system, this causes more air to be pulled in and metered by a MAF. So, without meth it may meter... let's say 800 cfm. But now the meth is on and every cubic foot is cooled and becomes 0.95 cubic foot... well, in a closed loop system that would cause a pressure drop. However, we're talking open loop, it just draws more air to compensate while maintaining the same pressure.

Thank you for being the man I didn't know I should have been. If I could go back in time I'd have joined and stayed in for 20 plus.

LS6427

iTrader: (2)

So you're saying anyone spraying more than 4psi needs to remove the MAF because its hurting performance?

Also....just curious.....doesww anyone spray meth right before the IC and then spray again right before the air enters the intake? Just curious.....would
there be a benefit in cooling the hot charge air two times?

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LS6427

iTrader: (2)

No FMIC......really? But it can only help right? Because my kit includes the pipes for a FMIC. Going to use the Bell 4.5".

Yes, I am removing my MAF and doing a SD tune for sure.

I'm over here in Dubai, private pilot for a billioniare. Not military. I was in the AFROTC in college at Embry-Riddle Aeronautical Univ, had a pilot slot, flew fighter jets while in ROTC and then BAMMO.....Bill Clinton slams us with massive military budget cuts in 1992. They took 50 out of 52 of our pilot slots at my college alone. So I just graduated and started my career as a corporate jet pilot. But my goal in life was to kill bad guys by the thousands........

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svslow

I would certainly keep the intercooler.

JoeNova

No. Density won't matter. The MAF will read the volume of air flow, and fuel will be adjusted accordingly. You're not suddenly creating more air inside the intake by increasing density. If you increase the density, then more air will have to flow through the MAF to compensate.

kingtal0n

iTrader: (1)

The difference in air temp is generally negligible when using methanol or water injection, unless the setup is somehow inherently inefficient or deficient in some way (too small of a turbo, no intercooler, too short or wrong type of plumbing i.e. poor planning, etc)

The main benefit of water/meth is the transitional change from liquid to gas state, which mostly occurs in the cylinder in traditional setups, after the intake valve is shut, thus no change in air density is perceived due to any cooling (since the valve is already shut, air molecules can no longer pack into the cylinder). Water carries a lot of energy (reduces temp) away with it (like pouring water on a fire) in the cylinder during combustion (as liquid molecules "get away" from each other and go off on their own as gas state molecules) thus holding down EGT (combustion chamber temp) and reducing output. Consider that combustion may hit 1500*F+ whereas water evaporates around 212*F. The phase change of water, although it occurs even at freezing temperatures (which is why food will "freeze dry" in the freezer, and why ice cubes shrink, as liquid water molecules turn to gas and escape the surface of the ice) will not completely occur to the injected liquid in an engine prior to ~212*F (so called atmospheric boiling point), so if the air in the intercooler is below 212*F at atmospheric pressure for example, There will be no phase change there, and thus no reduction to IAT below that temp, whereas in the combustion chamber temps are much higher than 212*F, thus all of the water is guaranteed to change phase to a gas while in the cylinder during combustion.


To elaborate, Some will inject meth/water prior to the turbo in order to facilitate IAT benefits, thus causing more liquid->gas phase changes in the plumbing prior to the cylinder, however, there is a maximum return on phase change temperature drop depending on the heat capacity and phase change temperature of the liquid(s) being injected. In other words, if the air is already at a low enough air temp(like mentioned above) due to intercooling or efficient turbocharging, there will be very little IAT drop due to meth/water injection, because it is not effective below a certain temp. In such setups, 100% meth is often used because it will cool the air to a lower temp than water, giving more of an IAT drop, although this is still considered a band-aid for inefficient systems in my opinion, and having 100% meth in the air supply pipe for the engine could be dangerous.

In any case, the person tuning the setup needs to be aware of how these systems work, and there may be a slight difference in procedure, but overall it is depending on the type of setup (racing or daily driver) with how much head room and safety is built into such a system. On most daily driver setups, reliability is a main concern, and as the boost pressure is typically reasonable on such setups (12~psi on 93 octane for example) there is not much needed to change in the tuning of the engine when adding methanol to such a setup (the meth will only make the system richer, and more safe) which will reduce power if the boost is left at the same pressure. If the quantity of injected meth is too high, some slight changes can be made to the tune to reduce the fueling from the injectors, or else more water can be mixed into the meth. On the other hand, if you are adding meth while seeking improved power output, you will wish to increase boost pressure along with the additional methanol injection; this is the opposite of conservative and reliability, since anytime the meth runs out or the pump fails, the engine will be at risk, although such systems are typically fairly reliable (I hear more failures due to "I forgot to check and the bottle was empty" than "the pump failed"). Generally in such a situation the meth is acting as a fuel source to cover the additional air from boost pressure, and traditionally this setup is preferable to adding fuel from the injector (at 93 octane) when raising boost pressure, although several fail-safes should be in place to ensure the meth is actually going into the engine. Since the meth is acting as the fuel source, the ECU doesn't need to be changed for the additional boost pressure (if you wish), since you can simply increase meth injection and concentration (less and less water) as you see fit to gain the desired A/F ratio.

SethU

Damn!!! Dubai is another one of my things. Fortunately I'm not past any age windows to prevent me from that experience. At 42, I'm not old, just too old to recruit.

A FMIC will increase charge density. However, so will more boost. And running E85, detonation won't be an issue until possibly into the 40psi range.

Spend the money on an intercooler if you like. However, the option does exist to not run one and just turn up the boost. Then you'll save the money and also however much the intercooler and related plumbing weighs... let alone the headache of mounting and plumbing it.

I'd personally not run one and see if I feel like adding one afterward. There is some possible benefit to having one, but will you need it?

What's the intended use of the car?

SethU

A couple nitpicky things...
Water doesn't carry away anything. It absorbs thermal energy and expands. Just as the other gasses do. Something I'm in the middle of determining is, how much does it expand for how much thermal energy it absorbs? There may be a finite balance of how much you can introduce into a combustion event that may actually produce a gain in cylinder pressure, where too much would in fact result in a net loss of cylinder pressure and reduce power output.

Also, water BOILS at 212ºF at atmospheric pressure. Care to guess what it might be under cylinder pressure? I haven't calc'd it out yet, but I'm curious if it reaches it's boiling point somewhere in the compression stroke prior to ignition, or if it does in fact need the heat of combustion to push it past that point, which also comes with elevated pressure, pushing the boiling point even further up. At what point do the conditions exist to boil?


Mostly true, however not entirely true. The fine misting nozzles do help air droplets evaporate at temperatures below the boiling point for the liquid at a given pressure and there is absolutely temperature drop directly associated to the latent heat of evaporation of the liquid that occurs at temps notably less than the boiling point.

kingtal0n

iTrader: (1)

I use simple words, easy to understand conceptualization, and then elaborate when necessary. When a water molecule "evaporates" it "leaves" its group of others- it becomes a solo molecule in a gas state, thus, it "carries away" its chunk of energy as it leaves the group behind. You could say "absorbs" but even I can nitpick this and say that the energy is invested into translational, transitional and similar (twisting, jostling, etc) movements of the molecular bond energy, and so on and so forth until we are discussion electronic configuration and cloud orientations.

I mention several times atmospheric pressure and use the term "generally" to indicate there are loose conditions. Both of us know that water is a byproduct of combustion- yet many readers will not have this in forefront of their thinking when discussing water injection, nor do many readers (including myself) understand completely how HOOH and similar molecules play a role in the act of combustion. There has been a fair amount of research done on the subject of using water to replace up to 50% of fuel, for example, where water is assumed to play an active role in the process.

This misting nozzle and high pressure may play a role- but then so does the whipping, flurry action of moving air through the plumbing, and the whirlwind of activity in the intake manifold and around the valve, and so forth. This is why I clearly made a point to mention that even at freezing temperature there is some evaporation occurring; I have explicitly implied that yes, evaporation occurs below the boiling point, whether we are whipping it up in the intake or letting it freeze into a cube in the freezer, some water is able to escape. These molecules are generally considered negligible in the scope of water injection tuning, however, for the majority of applications it will not significantly reduce IAT. Notice the use of my word, "completely". It was 100% accurate to say that the water injected, although some portion would evaporate, it would not completely evaporate.

stevieturbo

In simple terms, spraying liquid of any kind, nevermind methanol onto the MAF will kill it very quickly.

kingtal0n

iTrader: (1)

good MEthanol thread with some calcs
https://ls1tech.com/forums/forced-in...or-outlet.html

ddnspider

iTrader: (26)

That's completely false unless the tuner sucks.

ScottyBG

One thing I disagree with is the phase change of both water and methanol injected into the intake tract happens long before the intake valve. Water and methanol exist in both the vapor and liquid phases well below the boiling point. That's why we can smell fumes from the methanol. That's why we have relative humidity. There is plenty of water in vapor state even at 100f. Even more with methanol. The nozzle sprays the liquid into a fine mist to maximize the surface area so more heat can be absorbed, like fins on the radiator increase surface area. It is possible to show IATs below outside temperatures with an efficient nozzle. 50F IAT can be achieved of a 90f day. Ever stand in front of a fan soaking wet, there is a lot of heat being absorbed and you are far below 212 degrees. If the nozzle and such is set correctly the entire phase change occurs before the intake valve. None of it should be in the cylinder. This latent heat of vaporization significantly reduces inlet charge. Aircraft engines often form frost on the intake manifold and carburetor on hot summer days from fuel evaporation in the intake tract, even at low altitude. Almost all piston engines are capable of routing warm air from the exhaust into the intake to melt out this frost. None of the phase change should be occurring in the cylinder or you are not set up correctly.

kingtal0n

iTrader: (1)

It sounds good in theory, but consider this. If all the liquid, or the majority of the liquid evaporated prior to being ingested by the cylinder, then there would be no phase change in the cylinder, and there would not be as much of significant EGT reduction or cylinder pressure safety feature.

Fuel is injected in a puddle to the intake valve. It sits there, liquid state, waiting for the valve to open. The methanol and or water would generally do the same thing; there isn't any way I could comment or see for a large quantity of liquid to evaporate, whether gas, water, methanol, prior to entering the cylinder and being whipped around I would have to surmise. I would be interested in some hard data, though.

And before anyone says anything about EGT I am using this term synonymous with combustion chamber temperature, which is where the exhaust gas was a split second before it became exhaust gas (I draw no distinction).
random searchs:
http://www.dieselarmy.com/engine-tec...nol-injection/
http://www.turbomirage.com/water.html
http://www.superstreetonline.com/how...nol-injection/
I am not saying all of the injected liquid waits to be in the cylinder, obviously some of it evaporates prior. But I am saying that there is a good chance that the majority of the detonation resistance action comes from the phase change occurring in the cylinder, as it participates in the combustion reaction.

ScottyBG

In dealing with a corporation who designed methanol injection for piston engines, one of the key factors in the design was to be completely in the gas state before reaching the intake runners. I am a Chem Eng by education with specialization in combustion engineering. However I readily admit I no longer work in that field now, I moved into chemical coatings. If there is material in the liquid state, you get uneven distribution to the cylinders, so you may be fine in one cylinder, and have knock in another. This is why multi port fuel injection exists, it removes this requirement. It is fine to have main fuel from the injectors in mist like liquid state, because you have 1 per cylinder and that keeps it even. If you have liquid from an individual injector in the intake tract prior to the throttle body, if it is not in the gas phase it doesn't get to the rear cylinders in nearly the quantity it gets to the front cylinders. That is why methanol pumps work as high as 250 psi, to enhance atomization, which increases the rate of the phase change to gas, I would contend that the water lowers the combustion temperature, and thus EGT, just like taking timing out does, or using higher octane fuel does, it slows down the reaction, and reduces maximum cylinder pressure. The reaction kinetics calculations support this, the presence of a non reacting material like water, reduces the concentration of the reaction components. Reaction rates are always a function of the concentration of the reacting components.

There may be systems out there that are not fully vaporizing it, but they are operating at less than optimal performance if they are. I would deem them broken, or not properly installed. However this is really getting off topic, the Op really just needs to know that he doesn't need his MAF, toss it, and put a SD tune on the car, and life will be good for him.

One thing that may help the original poster though is, I would recommend using pure methanol. It makes it almost idiot proof, and you don't have the loss of energy that you get from using water in the mix. It is easier to tune, I think it just works better. Cheap methanol inj kits don't like this because the pump gets tore up buy the pure methanol. Buying a good kit solves this problem, like Alky Control.