Water to air IC's

[JNR]

I've seen a few guys (mostly southern hemisphere) running the water to air intercoolers, but don't recall reading much about them. What I am mostly interested in is their effeciency and cost and is it worthwhile to consider changing the air to air for one.

Seems one of the biggest advantages is less pressure drop and would think quicker spooling/better response, but how well do they cool and how much liquid (liters or gallons) does a good system use and what sort of transfer fluid? Does it use an electric pump, or do people add an engine driven pump? How about the cost and what options are available?

Reason I bring this is up is putting my IC piping back on, I noticed how much room is there to put a nice IC there next to the engine in between the turbo and TB...Also, plenty of room to put the heat exchanger up front where the air IC is now. However, is it really even worth considering (down the road)...Figure I could get a decent amount for the system I have now and it works good and all and has a huge IC, nice piping, etc., but with all the tubing, there must be a good 2-3 psig drop.

 

[cheekychimp]

Think about it this way, why do you think very few engines in the world are air-cooled anymore? I am not saying that to be a smart arse, I am just pointing it out because you asked about cooling efficiency. There are better people on here to explain thermodynamics (Barnes/Curtis in 3 ... 2 ... 1) but basically there is no more efficient medium for removing latent heat than water and no more consistent method for doing it.

A water to air setup is more complex and can be more expensive to do properly (it also arguably has more potential points of failure) but you will find very few scenarios where an air to air intercooler will outperform a water to air. One possible scenario might be a circuit car which spends a considerable amount of time at very high speeds and with ducting to give consistently good airflow over a prominently positioned large air to air front mount. In almost every other scenario a well built water to air should out perform a similarly "sized" air to air mount.

To answer a few other questions, most water to air systems use an electric water pump but I suppose there is no reason why you couldn't use a mechanical one. One quoted advantage of the electric pump is that when stationary the coolant is still circulating and being cooled through the radiator/heat exchanger ready for the next session of boost. The amount of liquid you use is largely dependent upon whether you are using a heat exchanger and the size of that heat exchanger. The more liquid you have the more heat it can potentially dissipate but given the fact that water weighs a lot you will reach a point of diminishing returns. I'll let some of the guys running these give some indications on system sizing. There was a very good Australian site with some great information on water to air systems and their advantages/disadvantages. I'll see if I can find it for you.

 

[cheekychimp]

Here you ARE!

 

[ktmrider]

I did a bit of poking around couple years back when I was having engine cooling issues with a Trailblazer. Fix was re-installing the plastic undertray I removed to ease oil filter R&R and had been too lazy to put back. Tray helped force air thru the radiator, not around.

Back to the original question, the guys in the southern hemispere like A2W because they have better thermal exchange properties than A2A. Why? Ambient air humidity or in this case a lack of it. High(er) humidity levels take advantage of Evaporative Cooling effects in addition to the thermal exchange between the IC composite.

So back to A2W systems, they are only as efficient as their heat exchanger and IC temperature. Putting the IC inside the engine bay does exactly what you'd think unless you use thermal barriers/coatings. They also allow for alternate cooling methods like ice or, becoming more popular, routing the IC coolant thru an AC/refrigerant system. A2A guys are mounting N2O loops on the front/air facing surface to accomplish a similar effect or use water/meth sprayers into the IC again to utilize evaporative cooling.

Plumbing is your enemy with A2W and you still have to mount the heat exchanger in the frontal area of the vehicle. Complicated with more moving parts that can fail vs A2A.

 

[rdomeck]

click

A great company with great tech support. I am in the process of taking out my side/top mounted air to air. Spool up time was good, but couldn't get enough air behind it. That would be different for a water to air. Lot's of parts and plumbing to go with it. Also once the water is hot it takes a longer time for it to cool down....

Call the guys at Bell and get there .02 worth. I have been using them for years on custom projects. Not cheap, but they know their stuff!

 

[JNR]

Thanks for the quick responses and will look into those links a little later. I have a pretty good understanding and practical application of thermodynamics with regard to cooling and all, although it has been a few years since I worked in that field. We used to do cold plates and heat exchangers and it was quite interesting and a lot to it, as far as details and how to apply the various paths, fins/density and so on.

So, I guess my question was for more what is out there "off the shelf" that is superior and worth the expense/"labor" of changing it over from an efficient air-to-air. Meaning, say you are comparing a so-so design of a W-to-A to an outstanding design of an A-to-A, would you still expect benefits and that much. Hope that makes sense. I'm sure like anything else, there are crappy (design) units, 'decent' units and awesome units and of course a good price spectrum.

I do recall there being some really good transfer mediums (ammonia is one of them, but not such a good idea, lol) and fluids, but the pump(s) play a role and of course the air heat exchanger design. A lot to consider, although I'm sure many of these companies have done their homework.

I just remember the oem water to air IC I had on my Syclone was not that great, although that would like comparing an oem air to air that came on the galant to a monster aftermarket high effeciency unit with pertaining tubing and so on. Guess that is where I never got into water to air designs and thought of them as inferior; although that is not true once you open up the variables (aftermarket).

Hmmm, well this is something I'm going to pursue and if it makes sense financially I should go for it.

 

[curtis]

PWR barrel intercoolers are really nice and the laminova units as well. I was going to post links but the first two I thought of were already posted.


I just always remember 4 times better, as in water has 4 times the latent heat of evaporation. Then there's pressure. If you could find a pump or set of pumps that could run a huge mount of pressure it would remove even more heat. But the amp draw would be crazy.


Lightnings and cobras come with a bosch pump from the factory and do alright but when pulleys are added IAT go up. Just had a friend melt a piston in a 04 cobra but hot as hell that day and with a heat soaked system fell in to the "are ya chicken" Micheal J Fox roll race and sh*t went bad fast.

Yes he has a upgraded front heat exchanger and a larger tank but not large enough. When the new motor goes back in I'll probably be building an aluminum front bumper that holds an extra 15 gallons or so.

As for exchangers larger frontal areas over weigh the thickness, find the biggest most efficient radiator core and build one to fit. I noticed a VW or Audi radiator yesterday at a friends shop and it had a ton of fins compared to most radiators out there. Also make sure the core your going to use is a water to air core......... air to air has different fin counts and turbulators.


Something else ot address is sealing the sides of the heat exchanger, I'm actually cutting some 1/8 inch thick aluminum pieces today for a friends car before he goes to the dyno on friday. Car has had air pockets in the coolant and after getting those fixed finally went out for a ride and I monitored the laptop for about 30 minutes. Got a few WFO pulls mixed in with cruising, redlights and creeping into and out of boost. I watched the IAT's and saw an increase in cruising and idling more than boost. At speed or acceleration its passing enough air but at cruising speeds to idle back to cruising it inches up a few degrees each time. Plan is to run a flat plate across the top and seal to the bumper cover at about 3 degrees down angle then the sides will come out about 2 to 4 inches in an arch to match the cover and be welded on at 3 degrees towards the core. Everything I've read says the plates will be more efficient if mounted this way. Makes the air flow through better than being angled out like a funnel. Have to remember the IC might be 3 sq feet total frontal area but only about 30% is open for air to flow. After about 10 miles for driving in 35mph traffic we were seeing 108 to 118 averages but after a short burst then a hard pull was seeing 90 to 95 but then would go up after slowing down again. Car is only on 14psi for now. Boost by gear is going in and after the car gets ramped up to 40 to 45psi the temps will be insane. If I can get 20 degrees out will help tremendously.

Would like to add a fan to the system on the back of the IC core but he's going to be doing a different radiator later on so we'll seal it to the radiator and go that way then.

 

[alansupra94]

Always thought about this but weighed in the cost/dangers of it versus a simple CO2 intercooler spray setup and went against it.

 

[JNR]

This one is still pretty cheap!, of course he doesn't give much info on it and I have 0 dollars right now to spend /ubbthreads/images/graemlins/mad.gif