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wut
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Over the last couple of days I have been looking all over the net for info in this. It sounds very interesting. Has anyone tried this on their Supra. I know there has been discussion on this in the past on the board but I'm interested in some results and the techniques that were used.
 
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I have read up a little on this because I have the Aqua-Mist unit going in as we speak. From what I have gathered from the Buick G.N. guys, some Mustang guys and assorted other racers, run as much as much water/alcohol injection as you can (right before it so much the car bogs down like it is flooding). Lots of people are using methanol (the major ingrediant in products that remove water from the fuel lines). The are some other things you can add to cool the charge and give octane but you have to be careful because some are corrosive to the the pump, fittings, line, etc. I think most of them only inject when boost is substantial or near max. If you search on google for it you should bring up the same sites I read over.
 

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wut
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Discussion Starter #3
Hmmmm, this is what I am hearing too. Let me know what the results are when you car is done. The kit I was thinking about getting was the one made by SMC.

Anyone else out there with experience?
 

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wut
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Discussion Starter #4
ttt
 

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I may be the exception, but I am removing the Aquamist system from my car. I believe it works and is useful, but not on a Supra. If I had a normally aspirated car that I had added a turbo to I would definitely use it (because of the higher compression). If I had an RX7 that is prone to damaging apex seals when they detonate I would use it (just for safety margin), but on the Supra it doesn't fix our problem. Our cars are very good at avoiding detonation. On the street in anything but 80+ degree days people can consistantly run 18-20 psi without detonation. The problem is our turbos aren't very reliable/capable of maintaining anything higher. This means the Aquamist system isn't really going to allow you to run more boost on pump gas (basically it won't allow you to make more power). Since the Supra engine seems to handle minor detonation without a problem, the system isn't really adding a safety factor either. It may allow you to run a little more timing, but not really worth the trouble to me. It is probably useful on a single turbo Supra allowing them to run more boost on pump gas than they typically could. I did consider using it in the summer heat to help resist timing retard and reduced power, but in N.C. it's only in the 90's for 7 or 8 weeks out of the year. The system is useful on the dyno because it can help avoid detonation so you don't need race gas when you dyno.

Later, Steve
Just my 2 cents. :)
 
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I am a huge alcohol injection advocate. Kind of a hypocrite because I still haven't got around to installing one on my Supra, which needs it badly. Now that I am set on getting the AEM unit, and it is gonna have it's own control for alcohol, I am waiting till then to install mine.

But I agree with Steve that you don't need it if you are still using stock turbos. Alcohol injection serves two purposes:

1. Detonation suppression
2. Enrichment

It also is a awesome cleaner. Your intake manifold and valves will be sparkling after using alcohol for a month.

Considering BPU MKIVs need neither of the two main reasons, there is no point. Now if you have a single, I'm of the opinion that you can continue to use the stock fuel system up to 700RWHP so long as you get a big alcohol injection system that can flow 250RWHP worth of alcohol.

The problem (up until now) is that alcohol in large amounts (like 250RWHP worth) has been difficult to tune. This is because most systems basically are on or off. They go from no spray to full spray, at a user set boost point. This causes the car to bog, basically being flooded with alcohol when it starts spraying. Turn down the spray, and the bog goes away, then you don't have the flow you need at 6000RPM and 25psi. Dual stage systems help a bit (half flow at 10psi and full flow at 20psi), but still not what is ideal.

With the AEM unit, it sounds like you can use a fuel injector(s) (alcohol compatible ones of course) to have it come on gradually. Ideally you would want a duty cycle identical to your regular fuel injectors, that starts at say 10psi. You would have maybe 20% flow at turn on, and it would match your air flow as boost and RPM rise. No bog, and plently of flow.
 

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I agree with the previous two posters. Without the ability to run more boost, a properly tuned BPU car really won't benifit from it. People that have tried haven't gone any faster. HOWEVER, this is on WI alone. Alchy might negate the energy lost to vaporizing the water, I really have no idea. But if you don't think BPU cars benifit from detonation surpression try putting in race gas and running the 1/4 mi...

With a single however, you should be able to run 22 to 24 psi safely, or maybe more. I'm a hiprocrit too, I don't use it on my BPU car, but I love the idea. Seen gains of 30 hp from that extra 4 psi, and that was on a 2L DSM engine.

AnArKey, alchy kind of scares me. Most people run methanol correct? Which is corrosive to aluminum? I just don't like the idea of throwing something that is corrosive to my head and pistons into the motor. Probably a silly thing, I know. I'm guessing its alky's ability to add energy back to the WI process that makes it favorable?

Oh and I talked to a guy who used ordinary fue linjectors for WI, they rusted :( Aquamist makes a stainless steel low-impedence injector, but its $$$
 
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You need special methanol injectors. I'm trying to locate a source for 160lb/hr methanol injectors. Two will be enough for me, and one should be good for milder setups that don't need the extra enrichment I am shooting for. Or you could use nozzles and a methanol compatable solenoid (NOS part #16060). I suppose if the AEM can control the duty cycle of a NOS solenoid (I don't see why it would be any different than a injector), that would be the best way to go.

Don't worry about the methanol and the motor parts. It vaporizes and is gone. It's only if it sits inside aluminum parts or lines that you get problems. Trust me on this point. I have spoken with several people using aluminum heads and intake manifolds that have used alcohol for over 40,000 miles. When they opened their motors they said there was NO corrosion, just sparkling clean metal "you could eat off of."

Methanol actually adds power by itself, as it is a slightly oxygenated fuel. It actually brings some extra oxygen into the combustion.
 

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Ah thats good to hear! Especially that last part, didn't know it was oxygenated at all.

I wouldn't use NOS injectors, I've heard of them failing. I'm not going to put something in my car that my motor relies on if its not as reliable as EFI. Plus aren't they designed for much higher pressures? I know they certainly aren't designed for extended operation like on a road course. Solenoids can overheat.

Do you think these injectors will be able to pulse quickly enough for our engines? At 6800 rms we have 340 intake strokes per second, I know aquamist's injector can only go like 240 / second, so some of the alky might 'miss' a cylinder. I guess the best solution would be an alky injector on every intake runner :)

Do you think these injectors would be compatible with straight distilled water? You run a 50/50 mix right?
 
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