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  #11  
Old 24-06-2004, 01:05 AM
cheekychimp cheekychimp is offline
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Richard,
Take a look at these :-

http://rallynuts.com/motorsport/DEI_Components_1724/ scroll down to Intercooler Sprayer

http://www.machevo.com/ninch.html

These systems are available

Paul.
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  #12  
Old 24-06-2004, 11:20 PM
Richard L Richard L is offline
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Quote:
Originally Posted by cheekychimp
Richard,
Take a look at these :-

http://rallynuts.com/motorsport/DEI_Components_1724/ scroll down to Intercooler Sprayer

http://www.machevo.com/ninch.html

These systems are available

Paul.

I visited the links, it looks wonderful and the claimed power increase and temperature drop was amazing.

I did some search on the net on "user report" of the product and found nothing so far. It would be great to hear from the user's side to support the claims of the manufacturer.

What do you think? it looked to me it is a win/win product !
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  #13  
Old 25-06-2004, 04:23 AM
hotrod hotrod is offline
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Default Super coolers

The DEI system makes me nervous for a couple of reasons. I called the company to get clarification (they claim a percentage cooling in their ads)
It wasn't clear if that was absolute temp or normal thermometer temperature, so I called for clarification. I was not impressed with the person I talked to. It would be better if they claimed a delta T of x deg F from ambient.

The second issue that came to mind is the potential of ice shedding off the cryobulb in humid conditions. That could pose problems with a combined WI system, depending on where the bulb was located. I'd hate to have a big chunk of ice come off and block the throttle plate open.

The N-tercooler system could potentially ice as well but it would be more likely in my mind to simply choke the system down as it strangled the intercooler. That would be a much safer failure mode for iceing when talking about brutally powerful cars.

The N-tercoolers definitely work, several folks have documented power increases from about 15 - 40 hp. My guess is it would be better if they claimed a percentage of normal hp increase. Obviously cooling the intake charge on a 600 hp engine will do more than on a 150 hp engine.

The down side of the N-tercooler system as I see it are:

Its very wasteful of Nitrous, and only CO2 makes much financial sense.

They can cause problems when used on cars that have limited head room on the fuel system as they push the fuel system into static flow if it is already working at high duty cycles. This form of lean out has been documented with engine logs.

On Dynos, they can cause tuning problems. On the CO2 systems if the air circulation and intake system work to pull CO2 into the air filter, they can cause significant power drop. If the same situation occurs with Nitrous the system can go dangerously lean on a chassis dyno.

I do like the concept of the N-tercooler, but think it needs to be re-engineered, and that is one of the ideas I'm looking at on my hybrid system. I have the CO2 bottle and am working on a new approach to how the intercooler is chilled. I have a design in mind, but am not at a point where I am ready to discuss the details of it. I hope to have a working prototype here in a couple months if not sooner.

They are also over priced in my view, as a simple aluminum tube loop with 30 odd holes in it and a solenoid plus tank is not worth nearly $600 in my view.

Larry
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  #14  
Old 25-06-2004, 09:05 AM
Richard L Richard L is offline
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hot rod,

If you are looking into making a product of chilling the charge air, why not use a water/methanol droplet as a media, imagine thousands of water/methanol droplets each with its own surface area, making contact with the charge air within the entire inlet tract rather through laminate-flow cooling via surface conduction.

All you need is an efficient heat exchanger - since the heat transfer is in liquid form (water/CO2-expander), it can be quite small.

I have seen this done sometime ago but never looked too closely into it.

You also have thousands of ready-make customers out there!
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  #15  
Old 25-06-2004, 04:10 PM
cheekychimp cheekychimp is offline
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Richard,
Could you explain, that last post more? I find it very interesting but I don't understand exactly how it works. Why do you need a heat exchanger?

Paul.
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  #16  
Old 25-06-2004, 04:39 PM
cheekychimp cheekychimp is offline
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Larry,
How cold would air in the intake tract need to get before ice formed on that bulb? I mean could it form on impact? I guess it's hard to force air to chill without offering it a surface to freeze on.

Could we chill ... PRIOR ... to the air filter? In the fender and out of the engine bay

The DEi system has a intercooler 'chiller' as well if you scroll down, that runs off Co2 (obviously much cheaper).

I wish you'd tell me more about YOUR designs ... 8)

If you are interested ... this is one of mine.

http://www.opconab.com/laminova/page...&x=lay2&y=img2

I want to run one of these with Evans NPG+ coolant in

http://www.evanscooling.com/main21.htm

The coolant reservoir will be in the trunk in a double skinned tank, the outer part of which will contain ice, to cool the coolant.

I may run hoses from a/c system to further cool this chiller.

Finally, as the ice melts it will drain off into a water reservoir to be utilised in the Water Injection system.

Comments ... please !!!
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  #17  
Old 25-06-2004, 07:08 PM
Richard L Richard L is offline
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Quote:
Originally Posted by cheekychimp
Richard,
Could you explain, that last post more? I find it very interesting but I don't understand exactly how it works. Why do you need a heat exchanger?

Paul.
All I am trying to say is to "super-chill" the water/methanol mix before injecting it into the air stream, this way you are getting a more direct cooling.

You need some sort of heat-exchanger to cooling the water/methanol down first.
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  #18  
Old 25-06-2004, 08:03 PM
cheekychimp cheekychimp is offline
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Larry,
Could we do that with the DEi cryo intake system? If we used a 50/50 methanol/water mix (which doesn't freeze) and pump it past the cryo bulb, immediately before we inject it into the intake tract, wouldn't that work?

Paul.
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  #19  
Old 27-06-2004, 06:51 PM
JSMC JSMC is offline
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Default Re: Some observations on compound systems

Quote:
Originally Posted by hotrod
Pure water injection -- Has some charge cooling effect and modifies the effective octane of the fuel air charge. In large quantities it needs leaner mixtures and more ignition advance to produce max power. It has no significant effect on the effective fuel air mixture (ie does not increase or decrease available fuel oxygen ratio). It is less effective when air charge is cold and at high relative humidities. Can freeze out of the air charge if intake temps go too low, liberating significant latent heat of evaporation and solidification back to the mixture, in effect fighting other super cooling systems as temps go significantly below both the dew point of the mixture and the freezing point of water. There is potential for ice build up due to super cooled water dropplets freezing on contact with surfaces at very low temps.
I'm sorry but I don't understand the part where you can have ice build up in the combustion chamber!! if you can explain this to me that would be nice! since it's hard to believe that near an explosion you can find temps that are that low they can turn the water to ice!!

I too have a question, can their be a point where cooling would make loose power instead of making some??

I got some ideas in progress that would enable me to obtain almost ideal temps for few applications.

what I have in mind is :
-fuel cooling, can bring it to a temp that would be benefical, if that exist?!
-water/air intercooler, the cooling liquid would be able to go very low, but is their a point where I can loose power from too low intake temps?
-water/methanol injection, here also I would have the possibility of bringing the temp pretty low, can their be a point where it won't be benefic?
-propane injection, well I can't really low those temp!!

my goals are HIGH rpm on a 4 cyl built for it, 10:1 CR, and as much power I can squeeze in it, since this would be a multi-stage performance car (eg stage 1 for street uses, with rpm limitation, no injection, low boost,... up to stage 4 which will make huge power for drag racing).

so anyone have an idea if this would be overkilled cooling system for the big power stage??
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  #20  
Old 28-06-2004, 02:15 AM
hotrod hotrod is offline
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Quote:
Could we do that with the DEi cryo intake system? If we used a 50/50 methanol/water mix (which doesn't freeze) and pump it past the cryo bulb, immediately before we inject it into the intake tract, wouldn't that work?
Yes that would work but is not terribly effecient. The cooling capacity of the small amount (mass) of liquid is not all that significant. If your flowing 10 - 15 Kg /min of air and injecting 300 -400 gms of water /methanol its specific heat capacity is only a small fraction of the heat capacity of the air. The evaporation process or a conductive heat exchanger has far more ability to cool the air charge. The basic process has been used for years in specialty racing environments like land speed record runs and drag racing, where they would use acetone chilled by dry ice as the coolant liquid in an air to liquid intercooler. (NHRA now outlaws these systems due to the hazards of the super cold acetone during an accident and fire risk if it gets sprayed around from a leak)


Quote:
I'm sorry but I don't understand the part where you can have ice build up in the combustion chamber!! if you can explain this to me that would be nice!
I was not talking about in the combustion chamber but in the intake tract. As the very small mist dropplets passed through and mix with the CO2 or Nitrous plume they could flash freeze to ice crystals which would liberate a lot of heat from the latent heat of fusion of the water that would be better used to cool the air.

Quote:
I too have a question, can their be a point where cooling would make loose power instead of making some??
Yes there is a point of dimishing returns, as the intake mixture gets colder and colder it becomes more effecient at drawing heat from the intake manifold etc. The result of this is it gets very difficult to get and maintain very cold intake temps.

In theory a drop in absolute temperature should be as effective at increasing power as an equal increase in pressure but that is not the case. Most mathmatical simulations vary the power at the square root of the temperature for a couple of reasons. Critical flow through an orfice is determined by the local speed of sound, hot gasses have higher sonic flow speeds and during the low lift portion of the intake valve where the pressure ratio across the valve exceeds 1.89 ( the pressure ratio required for critical flow) a hot intake charge will flow faster than a cold intake charge.

Also the issue of heat pickup from the intake and manifold and intake valve becomes more important as the intake charge gets colder. For an extreme example -- suppose you had an intake charge that was at 400 deg F, -- your 180 deg F intake manifold would now act as an intercooler and draw heat out of the air charge rather than warm it.

It seems based on those issues that density gained by lower intake charge temperatures is not as useful as the same density change achieved by increased pressure. (ignoring the change in detonation sensitivity)

Your VE will go up due to the cooler denser mixture but at some point you need to modify your ignition timing to compensat for the slower inital period of combustion.

There is a rule of thumb in chemistry that every time you increase the temperature by (IIRC) 10 deg F, the speed of reaction doubles. In the first moments of ignition the spark forms a kernal of flame about the same diameter as the spark plug gap. This small kernal has very little volume and lots of surface area, so it loses heat rapidly. It grows slowly (compared to normal combustion) for the first few milliseconds of the combustion stroke before it warms the surrounding fuel air charge up enough for very rapid combustion to take place. It then grows exponentially until a large fraction of the fuel air charge is burning.

If the fuel air charge is too cold, it is difficult to create and maintain a combustible mixture because the gasoline only burns when it is in vapor phase. The dropplets effectively only burn on their surface as they warm up enough to release combustable vapors. (one of the advantages of the propane is it side steps this issue due to its very low boiling point being essentially 100% vapor when it enters the combustion chamber).

If you cool the mixture too much you need to richen up the fuel air ratio to maintain combustion ( thats why cars run rich mixtures on cold start conditions). You also need to add ignition advance to compensate for the slow combustion process to maintain MBT timing.

Larry
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