[QUOTE]Originally posted by Hybrid
[B]Ultimately in a street app I think the water is going to contribute heat to the charge. Ie: If the car is continually stopping and going the water is going to heat up quite a bit b/c you've got no real flow over the heat exchanger.

 

Terry@spool sorry to hijack your thread!!

 

" After doing some quick thermodynamic calculations of the air/air set-up and the air/liquid set-up the air/liquid would cool better. But, the calculations only prove theortical values, not real world cooling capabilities. The underhood temps of the car would be high, and having the water sit in these conditions it will heat soak the water. Its possible to overcome this by having an extremely large front mounted heat exchanger and resevior, but even then the heat exchange can never by 100% efficient probably 80% at best. Now using these assumptions, redoing the hypothetical situations once again with thermo the air/air intercooler would yield a greater cooling capacity. You cannot argue with thermodynamics. I have found that when doing testing with design work, some design programs like Transcalc produce theortical values that are usually 20% off from the real world values measured. This only leads me to believe that while on paper the air/liquid intercooling seems very good, for real world purposes (i.e street driving) it cannot be as efficient."

"Hey boosted hybrid, when you did the test on paper...did you account the air to air unit to be at 100 percent effic.? cause if the water to air unit was only at 80 percent, would the air to air unit not be at a lower percent as well making the water to air unit more efficient again. It really really does depend on size of the fan and heat excahnger as well and how much water can be filled in the system too I guess."

"Well you are right to a certain extent. In a perfect situation the water would cool the air down to lower than ambient. But, with the water getting heated up by the engine compartment the water now carries more energy. While water does cool superier to air, when the water carries more energy its cooling capability deminishes. If look water carries a higher specific heat at 0 degree celsius (4.23 kJ/kg*celsius), than at 75 degree celsius (4.18). While this doesnt effect the water as the cooling medium, the temperature is effected by the heat. Now water does carry the greatest latent heat of vaporization, but in this situation the heated water will not cool the hot air better than an air/air."

quotes from others.

 

Nice quote hybrid. Can you tell me the source?

Good info.

 

Honda-tech.com

"Intercooler efficiency = compressor outlet temp- intercooler outlet temp
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compressor outlet temp - ambient air temp

Now, with an air to air you only have to figure the ambient air temp. With water to air you have to figure the water temp which needs to be figured again with the heat exchanger efficiency. With air temp and water temp being equal a water to air is obviously better. However, it's very hard to get the water down to ambient temp and keep it there. With the air to air you have an unlimited supply of ambient air to cool the ic. What it really comes down to is what can you get the temp. of the water down to? You figure on a 100deg. day the water starts at 100deg. Now, it's sitting in a hot engine bay and it's going to get to around 130-150deg. Now you have the heat exchanger trying to cool this down to ambient. On top of that you have hot air running through the ic transferring heat to the water. Again, the heat exchanger trying to cool to ambient. Most good air to air ic's are about 83-88% efficient and most water to air are about 93% effiecient. However, the water to air efficiency is relative to the water temp. It is possible to have an air to air more than 100% efficient with ice water as the cooling media.
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Jotech Motorsports
http://www.jotech.com
8.94 @ 172.4
8.59 @ 170"


This one is from chief tech at Jotech, for some reason he hates vortech, especially Trevor.

 

An air to water system will have much more thermal capacity than an air to air, which should help keep the intake charge cooler longer when the car is stopped. However, once the water is heated up, it will take longer for it to dissipate that heat too once the car gets moving again.

 

[QUOTE]Originally posted by gernby
[B]An air to water system will have much more thermal capacity than an air to air, which should help keep the intake charge cooler longer when the car is stopped.

 

Lot of excellent points and I will attempt to sum it up. For drag racing nothing will beat the efficieny of an air/water setup. Especially if the water is iced or dry ice is used to cool the water.

However on the road an air/air by far is the superior setup since the water medium once heated takes longer to cool or dissapate the heat.
Water/Air higher efficiency ratings are excellent for the track

Air/Air is superior to real world conditions.

Also remember the source quoting the superiority of the air/water is vortech, and it just so happens that thats what they utilize. It would be more fair to utilize an independant source like Corkey Bell's Maximum boost for an unbiased reference

 

yeah but Corky Bell is about as flaky as they come!
You ever try to do business w/ that guy?

 

I'm interested in a stage 3 with AEM!! When will that be available?