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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 12:22 pm 
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Joined: June 5, 2016, 7:03 am
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Location: ontario
banzairx7 wrote:
phil wrote:
Thanks for the idea.
However the main ingredient in my mixture is H2O, not ethanol or methanol although the latter have often been used in the 50-50 water mix. Ethanol is there to keep the water from freezing. Yes it burns too and contributes to prevent detonation. Water is the main thing in head temperature reduction. All this dates back to WWII. In my system I have made a 6 gal aluminium tank. I still have to figure out metering. nozzles , a pump, etc. I expect a fair bit of trial and error too. My engine is a 6 cyl air cooled engine with a 10-1 compression ratio. Adding supercharged boost would place the heads (valve seats) in great danger of overheating . My hope is that water droplets will prevent that and even add a few horses.


I don't think you've got that correct. The methanol is what is giving you the cooling and the anti-knock. It's definitely not for an anti-freeze. The only reason most people run water is because it makes the methanol non-flammable for shipping purposes. Boost juice, Snow Performances meth mix, is 51% water for that reason. The more alcohol you run the higher your octane and cooling effect will be. Drag cars running alcohol don't need cooling systems because of the cooling effect of the fuel. That's not to say water isn't helping but it's help is during the combustion process. It keeps combustion temps down. The phase change from liquid to gas sucks up a lot of energy and hence the flame temp is kept down. It's effect is not nearly as pronounced as the alcohol though.


Hi, I won't pretend to be an expert on this. All I know is based on what I picked on Wikipedia :

...."Water has a very high heat of vaporization. As the ambient temperature water is injected into the engine, heat transfers from the hot cylinder head and intake air into the water. This makes it evaporate, cooling the intake charge. A cooler intake charge means it is more dense (higher volumetric efficiency) and also has a lower tendency to knock. However, the water vapor displaces some air, negating some of the denser intake charge benefit. Knocking is generally more of a problem in forced induction engines rather than naturally aspirated, so this can help prevent it. On electronic ignition systems the ignition timing is generally retarded to prevent knock from occurring but with water injection it can be advanced closer to maximum brake torque (MBT) timing for additional power.
Composition of fluid.
Many water injection systems use a mixture of water and alcohol (often close to 50/50), with trace amounts of water-soluble oil.

The water provides the primary cooling effect due to its great density and high heat absorption properties. The alcohol is combustible, and also serves as an antifreeze for the water. The main purpose of the oil is to prevent corrosion of water injection and fuel system components;

 it may also assist in engine lubrication when running in a high power state. Because the alcohol mixed into the injection solution is often methanol (CH3OH), the system is known as methanol-water injection, or MW50. In high performance automotive applications some tuners use 100% methanol as opposed to a water-methanol mixture and then referred to simply as "methanol injection". Safety concerns and part longevity concerns keep this as a controversial option. In the United States, the system is also commonly referred to as anti-detonant injection, or ADI..." :)


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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 2:12 pm 
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Mid-Engined Maniac

Joined: April 23, 2006, 8:26 pm
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Regardless of its cooling abilities, you're going to find the system a pain. I had a water/methanol injection setup and it's another thing that takes up space, including controller, pump, and where's the 2-5 gallon reservoir going? Then there's dealing with the jet(s) plugging up, which can lead to to engine failure if the engine tune counts on it functioning. Lastly, there's always being aware of how much coolant remains and whether you have enough to get home. Real systems have all sorts of safety features to ensure that coolant flows when needed, but they cost $$$. Yes they work but for me it just wasn't worth it and I ended up going with a big air/air intercooler.

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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 3:56 pm 
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KB58 wrote:
Regardless of its cooling abilities, you're going to find the system a pain. I had a water/methanol injection setup and it's another thing that takes up space, including controller, pump, and where's the 2-5 gallon reservoir going? Then there's dealing with the jet(s) plugging up, which can lead to to engine failure if the engine tune counts on it functioning. Lastly, there's always being aware of how much coolant remains and whether you have enough to get home. Real systems have all sorts of safety features to ensure that coolant flows when needed, but they cost $$$. Yes they work but for me it just wasn't worth it and I ended up going with a big air/air intercooler.



Thanks for the warning. Yes I don't expect this water system to be a cake walk.
In my case the water reservoir was planned from the beginning, that is from designing the tube chassis. On my build the space under the front hood is roomy enough to receive the fuel tank, the water tank and a full size spare wheel.
To me a water cooling system is a must. The corvair engine is an air cooled engine and in 1965 my model was designed to run a 9.25 to 1 CR without forced induction. On the turbocharged models GM reduced the CR to about 8 to 1. Since I am not doing this I need something to protect the heads from overheating. I have consulted Corvair owners on the Corvair forum and was advised that water had been used successfully by racers for years. My engine will be equipped with a small supercharger run from the crank pulley and a waste gate set at 6 psi max. I plan to set my system so that on demand the boost will be disabled. When the boost is disabled the engine will operate under its stock design conditions and will not need water injection. If I run out of water a sensor will automatically turn off the boost. I already made my water tank out of 1/8" alu. It features a level gauge and I will add a low level red light as well as a sensor that will automatically turn off the boost. As I have indicated I am at the learning stage and I welcome advices and opinions. I have thought of intercoolers, yes a big intercooler would help, but on my car it may not be enough. Maybe I should have both.
To me the water injection system seems a good deal simpler than ECU ignition/injection.

You are right to say that these systems when bought as kits are not cheap. I do not plan to buy one of these on ebay or anywhere else but make my own . I understand that a workable water injection system (and in my case it is only water) needs to be designed for a specific car. I take that these off the shelf kits can be overpriced and in some case not be up to the task. Some sites are advocating do it yourself strategies as a means to keep the cost down and to make something that could work on a specific car
.
Turbomirage is one. I tried to link this to it and it did not work.

I have also read Autospeed- Water injection issue 419. Section: technical features. An eye opener. :)


Last edited by phil on January 6, 2018, 6:13 am, edited 1 time in total.

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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 4:45 pm 
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Boosting a high compression air cooled motor is like trying to tap dance on a razor edge. There will be bleeding.

You can easily do a turbo'd 4 banger and make twice the power for less money and better reliability.
There are so many better choices...

Using a Corvair power plant for the novelty is cool, adding boost boarders on self flagellation with barbed wire.

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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 5:52 pm 
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Bent Wrench wrote:
Boosting a high compression air cooled motor is like trying to tap dance on a razor edge. There will be bleeding.

You can easily do a turbo'd 4 banger and make twice the power for less money and better reliability.
There are so many better choices...

Using a Corvair power plant for the novelty is cool, adding boost boarders on self flagellation with barbed wire.




Thanks for your points.
Albeit rather somewhat theatrical, I found your warning useful and interesting. Corvair engine writers too have indeed warned against forced induction in this air cooled GM mill. On paper they were right and you are right. The flip side however is that given the right approach boosting air cooled engine with a CR up to 9.5/1 has been done by engineers who apparently knew what they were doing.

A quick flight over the web produced this link:

http://www.t-t-p.de/english/yt_964_993.php


I would not of course compare myself to this German firm. But the fact that they turbocharged air cooled 911s and lowered the CR from only 10 to 9.5/1 indicated that the whole idea is not as insane as you seem to believe. In my project the "fine print" is that the boost will never be allowed to exceed 6 psi and that an extensive cooling system will be present (water injection and possibly water cooled intercooler).


Last edited by phil on January 6, 2018, 6:17 am, edited 2 times in total.

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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 9:15 pm 
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Phil, if you're on the Corvair forums you may have already heard this, but here goes! Back in the day (60s-early 70s) I recall some of the Corvair racers using a sort of water injection to the cooling system. When running boost, they would pump water through nozzles that would spray a fine mist into the cooling fan to provide an evaporative cooling for the cylinders and heads. Might be worth looking into.

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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 9:23 pm 
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Joined: April 23, 2006, 8:26 pm
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My comments above weren't intended to imply that water/meth injection doesn't work - it most certainly does. My point is that it's a bunch of extra stuff that can fail, and if the drivetrain is designed such that it's counting on the water/meth injection to be there, what happens when it isn't? You comments about adding a float switch are good, but it's just the start. What about the nozzles plugging up, or the pump failing, or failing partially?

I'm all for quirky - I did my own one-off - but agree with the comment above about if you want a turbo engine, start with a modern 4-cylinder. I also agree with the comment that if you want to use that engine, okay, but leave it alone - adding forced induction is really inviting problems, as nothing about that engine was designed to handle it.

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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 11:16 pm 
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ngpmike wrote:
Phil, if you're on the Corvair forums you may have already heard this, but here goes! Back in the day (60s-early 70s) I recall some of the Corvair racers using a sort of water injection to the cooling system. When running boost, they would pump water through nozzles that would spray a fine mist into the cooling fan to provide an evaporative cooling for the cylinders and heads. Might be worth looking into.


Yes I heard that too and I asked on the Corvair forum about it. They said that unless I raced, injecting water into the carbs was all I would need. To this day I am following their hint.


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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 11:24 pm 
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I'm all for quirky - I did my own one-off - but agree with the comment above about if you want a turbo engine, start with a modern 4-cylinder. I also agree with the comment that if you want to use that engine, okay, but leave it alone - adding forced induction is really inviting problems, as nothing about that engine was designed to handle it.[/quote]


I think we have beaten this subject long enough. For the record the Stock Corvair featured a successful turbocharged model and later non turbocharged units have been converted successfully :)


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 Post subject: Re: EFI orientation help
PostPosted: January 5, 2018, 11:44 pm 
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Okay.

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