No intercooler...pure chemical intercooling?

[AnArKey]

Go here (neat page BTW):

http://www.aquamist.co.uk/rescr/faq/airmass/airmass.html

There is a section entitled: "CALCULATING THE EFFECT OF WATER INJECTION"

From my calculations, it seems doable to use no intercooler at all, and alot of 50/50 water/methanol to reduce charge air temperatures a huge margin, almost up to ambient. Hypothetically you should be able to (with enough flow) reduce air charge temperatures below ambient, but I'm not counting on it.

Using some rough figures of a turbo outlet temperature of 120C and a airflow in the 500-600HP range, it looks like only 15-25GPH of water would be needed to bring the temperature down around 20C-30C.

I'm gonna run twin stockers on Project-X, and as a result am not going to use very high boost, and not have turbo outlet temperatures much past 120C.

Also the fact that the water/alky mix will be meeting (initally) a MUCH hotter air charge than the traditional post-IC injection, the vaporization limit and rate should be much higher. This should naturally increase the "flow stall point" (point where engine bogs from too much water/alky).

Normally with this much flow, flooding becomes a problem. But since I have a FAST system with WB02, I can actually use and burn the methanol in the mixture (the system will reduce the amount of fuel as methanol comes in). I think this will also contribute to raising my "flow stall point."

Am I nuts or can this work?

 

[Steve Hill]

it should work and work well. Because the only reason for an IC is to remove unwanted heat from the compressed air. Otherwise an IC is just an unnecessary restriction in the air circuit.
I did some testing which also correlated with this presumption.

 

[AnArKey]

Some further study I have done. Water, although capable of removing more heat per volume than methanol, has the a couple disadvantages:

1. In high humidity (like Oregon, where I live) the amount of water that can be absorbed is limited. I don't expect to hit this limit, but it's there.

2. The water takes up some room in the air charge, reducing horsepower.

BUT, here's the good news. As far as I can tell, in my application (twin stock turbos, low boost, 14-19psi) where the heat level out of the turbo is pretty low (compared to say, 28psi), I can use pure or close to pure methanol in about a 50% HP fueling. Meaning that if the car gets 50% of it's power from methanol, the inlet temp should be close or even lower than ambient. I figure this to be in the ballpark of 0.75gal/hr-0.8gal/hour (for my combination). The advantage is that the methanol is a fuel, and will be used, rather than water which "just takes up space." Another benefit is a little extra horsepower from the fact that methanol is partially oxygenated, so my max HP from a given air volume is a bit higher with so much methanol.

I'm getting excited. I can't imagine the spool up with twin stockers pushing right into the throttle body with my new ATI 8" 3500 converter. Ohhhhh weee!

 

[bruce]

Originally posted by AnArKey
2. The water takes up some room in the air charge, reducing horsepower.

Amazes me you can say that.

What is one of the greatest rocket propellants?.
Hydrogen and oxygen.
What is water made up of?.
Hydrogen, and oxygen.

There a MANY REACTIONS that take place in a combustion chamber. Pre and post ignition, you might look a little further about what's actually going on.

There are classes of pulling tractor that have outlawed Intercooling so they have to do it all on the Water Injection. Might take a look at what they're doing for some clues.

 

[Steve Y]

The Buick powered Indy cars did not use an intercooler and were the fastest things around for a while.
Running on straight methanol is the reason an intercooler was not needed.
Steve

 

[AnArKey]

Bruce....I'm just going on some statements made at a few water injection places. The loss of horsepower through water "taking up space" I have not calculated, as I have no idea where to look. The suggesting is that any gains made through temperature drop (and density increase) will be offset by the water itself. This is purely a suggestion, and if anyone knows the clear answer, I'd love to hear it.

I never took thermodynamics in college, too busy learning useless computer code. Wish I had now.

In any case, it seems to me like this will work. The exact ratio of water:methanol and flow rate is going to have to be a ongoing experiment for ahwile. It will be heavy on the methanol, 66%-100%. At least using the math I have so far I am able to get a ballpark to shoot for. If on 80% methanol and .75gal/hr I hit 18psi and see my intake temperatures near ambient on the first try, I will hail the mighty math gods. But I know it's gonna be a bit trickier than that.

 

[bruce]

If you go over to the DIY-EFI site, and hunt around in the archives Robert Harris did a wonderful posting in layman terms about some of the reactions, that go on (some how Jun 11 00, rings a bell)

You have two very different things to consider,
vaporization,
and
atomization

vaporization gets you charge cooling
atomization gets you detonation supression.

Sounds like mumblelygook till ya stare at things for a few hours, and like I said looking at some pulling tractors will help ya.

Also, reading some of Sir Harry Ricardo will help.

FWIW youu can figure on running 1/4-1/3 of the fuel weight in water when done right.

 

[PRSRIZD_V6]

2 things I'm wondering here:

Don't pulling tractors run straight methanol anyhow?

Hydrogen and oxygen would be way more powerful than water due to a double bond in the molecule wouldn't it?

 

[Alky V6]

Run 100% Methanol. Don't waste the space with water. You'll love it! Why not back off the gas and increase the alcohol injection. Just make sure you can feed it fast enough and the nozzles you use are very precision in size. You'll need a lot of it. I know using nothing but methanol you would not need the intercooler. Using it just as a coolant over the gas, you might want to keep the intercooler until testing shows you no longer need it. I'm excited for you. Go for it. Join the revolution. Alcohol forever! Ahhhhh!!!

 

[AnArKey]

Well I don't have a intercooler. The car has been stripped of several parts in the last few weeks, intercooler included. So when Project-X goes back on, I have to commit to intercooler or no-intercooler.

Now the method is what drives me crazy the most. Two stage with solenoids, and hope the FAST can be programmed to drop out fuel as the methanol comes on? Maybe go so far as to run fuel injectors in the turbo pipe?

Does the FAST system pulse the two extra injector drivers? I use 6 for the fuel injectors, maybe I can use the other two to drive injectors on the methanol? Gonna pose this question elsewhere.

 

[Alky V6]

I don't know what the FAST is. Been away from the board awhile. If you run an engine management system that runs in closed loop and you can program in the A/F ratio you want, the system will back out the gas as the alcohol comes in. Hopefully the system would allow you to back off quite a bit if you decided to use a lot of alcohol. I'm using Electromotive with nothing but alcohol and in closed loop it adjusts to the desired A/F perfectly. This is using a regular O2 sensor, not a wide band.

 

[AnArKey]

FAST is what they call Speed-Pro now. Ok so I can count on the FAST with WB02 backing off the fuel as the methanol comes on...good. Since the on point of each stage will be at the exact some point everytime, I can program it proactive rather than wait for the WB02 to pull back the fuel (reactive). I will just have everything set and then tune the tables watching the level of 02 correction. You will probably see two distinct steps down in the fuel map as each stage is hit, once the fuel map is set.

Now here's a good question. Does mixing fuels cause a problem? If there is half the power coming from gas, and half from methanol, each mixture (looked at by itself) is dangerously lean. Will it behave like two seperate lean mixtures (going BOOM) or a semi-rich combined mixture? What should my target A/F ratio be (as measured in gasoline terms by the WB02)?

 

[Alky V6]

You won't notice any difference. The important thing is that if your going to use a lot of the alcohol, I would port inject it with one nozzle per cylinder to assure even distribution. Just 2 injectors at the throttle body may present problems. My motor liked an A/F of between 12.8 to 13.3. You can go as lean as 14.3 if you want, but I'd play it safe. As you add more methanol anyway the POWER increases. Treat the O2 sensor ouput just as you would with 100% gas.

 

[Alky V6]

Oh and mixing will present no problem at all.

 

[AnArKey]

Originally posted by DonWG
You won't notice any difference. The important thing is that if your going to use a lot of the alcohol, I would port inject it with one nozzle per cylinder to assure even distribution. Just 2 injectors at the throttle body may present problems.

Port injected it presents a problem. Done that way, the temperature drop doesn't occur until the methanol mixes with the air, it's already halfway in the cylinder. The intake manifold is still full of super hot 250F+ air. The charge density that the cylinders are sucking on, isn't as dense as if I injected the methanol right in front of the turbo outlet. That way, the methanol has a chance to vaporize completely, absorbing heat from the air, thereby the intake manifold will now see ~100F air. Remember cylinder heads flow in CFM (a measurement of volume), not air mass. You want the air in the intake manifold to be a dense (cold) as possible.

My thoughts go like this:

Remember this is a twin turbo, with the pipes from the individual turbos meeting in front of the throttle body.
Shurflo Pump
Methanol tolerant fuel pressure regulator
Fuel cooler using ice (Get that methanol nice and chilly)
2 large injectors spaced aprox 8" apart right after EACH turbo. For a total of 4 injectors

This should give in the area of aprox 24" of tube to flow through for vaporization. In that distance I would expect 100% vaporization. Since the air is so hot to begin with, it will vaporize VERY quickly. Compared to ICed cars, my initial vaporization rate will be several times faster. It will absoluetly drink the stuff up.

Pump would come on at 1psi. First pair of injectors on at 5psi, the second set at 10psi. The fuel pressure regulator will keep the system at a boost adjusted 45-50psi.

Hey Don, can you recommend a good FPR and injector source for methanol?

I may change this to a spray nozzle and solenoid arrangement if the cost of the FPR and injectors are cost prohibitive. I have heard that stock Bosch injectors from donor cars handle methanol well? Heard anything about that? "We found that the Bosch fuel pumps, fuel pressure regulators, and injectors will tolerate methanol." I got that quote from here:

http://www.dune-buggy.com/turbo/methanol.htm

The air temp probe will be in the very back of my PTE Plenum. I also plan to run the new RJC Power Plate.

I'll know the injector sizing and fuel pressure to shoot for once I grind some numbers.

 

[Alky V6]

I use a set of stock 84 GN injectors to flush the system with gas after testing, and alcohol has been run through them with no problem. The thimble filters plug quickly when using Alc and some will just leave them out. I prefer to change them on a regular basis (After a weekend of racing). I would be very careful injecting the alcohol before your throttle bodies. I understand that the charge temp will be up there and it will be hard for the alcohol to get the charge too cool, but keep in mind that throttle blades have frozen open before. Just watch your temps very carefully. As a personal general safety rule, I would never put 100% alcohol injection in front of my throttle blades no matter what the temps are. Ever see ice form on the manifold of a Methanol burner? What about injecting from the roof of the plenum. Let some of that alc get into the cylinder in liquid form to cool the chamber. The Indy guys that aren't running intercoolers. Look and see where they're injecting their alcohol. If your planning on the meth being a large percentage of the fuel on the top end, distribution is going to be very important. Alc likes to fall out of suspension a lot easier than gas.

 

[AnArKey]

Wait you are saying I might have a problem with FREEZING? That given enough flow the temperature is gonna go from ~120C to 0C by the time it hits the throttle blade?

Is there something wrong with my theory of maximum atomization time? If the methanol doesn't have a chance to fully atomize, won't the change air density in the intake manifold be less than if the methanol was 100% vaporized?

Why would methanol fall out of suspension, especially in a very rapid air mixing enviornment, at about half of it's stoich fuel ratio?

 

[Alky V6]

I agree with everything your saying. My guess is you'll be OK. But when experimenting like this, sometimes you'll come across circumstances that weren't counted on and I would opt to use a design with safety thought of up front. If your going to be injecting alcohol at 50% stoich, you'll need 6 80 lb injectors at 45 psi just for the alcohol. Assuming your targeting a HP level of over 600 HP. That's going to be a lot of alcohol going across those throttle blades. I'm not trying to bag your ideas, just presenting some food for thought. I'm looking forward in seeing how it turns out. I'm presenting calculations off the top of my head to get you thinking. I'll leave the hard math to you. I do know that with 6 160 lb injectors at 45 psi and an HP level of maybe 650, I needed about 30 lbs more per cylinder to get my target A/F. Which I never did achieve. Make sure you have a big pump.

 

[AnArKey]

I shouldn't stay I was shooting for a 50% HP rating of methanol. What in fact I did to come up with my flow figure to shoot for was to use some theromodynamic equations to determine the level of methanol flow at max HP to cool the air from the maximum forseeable intake temp to near ambient.

I came up with 270lb/hr

I am leaning towards running 12 (yes 12) stock GN injectors to serve this purpose. A little fuel rail of 6 injectors placed near the outlet of each turbo, running on a regulated system. The injectors will open static in stages. Probably 3 stage (4 injectors, 2 on each side at a time). This will provide 360lb/hr (figuring the stock GN injector flow rate of 30lb/hr) of flow at 45psi boost adjusted fuel pressure. If my calculations are right I should end up running more like 38psi of fuel pressure. Taking into account your comments on here as well as on your project page of how your car just never seemed to get enough methanol, I would be providing the potential to go about 50% past my calculated figure just by turning up the methanol pressure.

I'm gonna use a 1.4gpm pump (504 lb/hr), so that should be more than sufficient.

Yeah I'm moving 270 lb/hr of methanol, but the tubos are nice enough to offer ~4000lb/hr of super heated air at the same time. Mixing shouldn't present a problem.

 

[Alky V6]

Look for an unsteady O2 reading. That will tell you if the distribution is not up to snuff. That was one way I used to signal when the thimble filters in the injectors were starting to plug.