Thinking about water to air intercooler

[thiazole]

If I decide to do this, it is probably a year away (I have more pressing issues right now), but I was wondering if anyone has any experience with water to air intercoolers. The idea of one is attractive to me because they have so little pressure drop and are presumably more efficient than an air to air intercooler. I'm just not sure how "streetable" they are. The kits I've seen use a thin radiator to cool the water that you mount in front of the regular radiator like you would a front mount intercooler and the intercooler itself is much smaller and could be mounted in the side mount location. You then have a water pump somewhere else that circulates the water. I'm assuming this setup would have no trouble keeping up with the cooling demands and because water has such a large heat capacity, heat soaking would seem very unlikely under any circumstance. I'm not so sure how it fairs in the winter. I'd assume you would use some kind of winter blend (methanol mixture or maybe ethylene glycol) to keep if from freezing. Does anyone here use a water to air intercooler and if so, what are your impressions?

[D Walker]

I have used them a lot, and they work perfectly if set up properly. the biggest issue is coolant capacity, but that can be easily sorted out with good planning.

[Cloud]

I have used them a lot, and they work perfectly if set up properly. the biggest issue is coolant capacity, but that can be easily sorted out with good planning.

How do you mean? Meaning it heat soaks easily or what?

[ricehunter]

Well, from what I learned about them is that they do heat soak quickly, so not the best thing for the street. They're great for the 1/4, especially because you can ice the watter to keep it super cool.

As far as the routing, you could reroute the battery to the rear and place the LAIC in the place of the battery with an extreme sort rout system. I was thinking about doing a LAIC but I'm trying for track, but I've decided to go with the SSAC FMIC until I need a massive front mount.

[D Walker]

Im not going to write a primer on water/air intercooling, but honestly water to air is vastly superior to air/air in virtually any situations IF you can deal with the added weight and complexity over an air/air. Back in the day many people THOUGHT water/air was inferior to air/air, but those people were wrong and perhaps did not have a clear understanding of intercooling, or were basing thier opinions on flawed data. A few years ago I improved a water/air setup for a supercharged NSX and even turning the NOVI s/c at near explosion RPM, at Laguna Seca he could do a 25min session and the air temps were nice and low, and I PROMISE you he was in boost much more than your average street car.

[XakEp]

Well, from what I learned about them is that they do heat soak quickly, so not the best thing for the street. They're great for the 1/4, especially because you can ice the watter to keep it super cool.

As far as the routing, you could reroute the battery to the rear and place the LAIC in the place of the battery with an extreme sort rout system. I was thinking about doing a LAIC but I'm trying for track, but I've decided to go with the SSAC FMIC until I need a massive front mount.

Get a decent sized resevoir.

[thiazole]

I think as long as you have a big enough water tank and a decent radiator to cool the water that it would work fine. When I have time, I'll sit down and do the thermodynamics math, but I think a gallon of water could probably handle the 1/4 mile without a radiator - with a very efficient radiator, you could go indefinitely. The question is which is faster at heat transfer, air or water and I think the answer is water. The rest is just about getting the right parts.

[Cloud]

I think the biggest issue with heat soak is people don't run a large enough radiator for them. It's a large thermal mass compared to an air/air. The amplitude in heat soak is much lower but lasts a lot longer than an air/air setup. You might only heat soak maybe 15 degrees but it will last for a good long while compared to heat soaking an air setup to 40+ degrees at the end of each pass.

[D Walker]

I have posted this before, but here it is again:

http://autospeed.drive.com.au/cms/A_107796/article.html

Heat soak is the least of your issues with LAIC,the larger issue is the weight, the hoses and pump, etc.

[thiazole]

Yeah, that is a good point. No one ever mentions the efficiency of a water to air intercooler and that is probably a tricky thing to measure. You really couldn't say how efficient it is relative to the air temp, but only relative to the water temp. If the efficiency is significantly superior to an air to air intercooler, then a small amount of water heatsoak might not matter. If an air to air intercooler when the outside air is 70*F cools the boost charge to 130*F and a water to air intercooler when the water is 70*F cools the same boost charge to 100*, then you could afford a fair amount of heat soaking of the water before it gets worse than an air to air.

[D Walker]

Just as a sidenote- most Pro drift guys are going to LAIC because it is much more consistent and efficient than thier old A/A IC's.

Also, it needs to be noted that several drag racers have noted that a LIAC can reach 115% efficiency- ie: dropping intake air significantly below ambient, say IAT's of 75deg on a 90deg day. Even when the water is "heat soaked" with a proper heat exchanger setup the LAIC will STILL cool the intake charge as well as a A/A IC.

[Cloud]

It's the best setup for consistency. Once you get the initial heat interaction to bring the water up to a high enough temp to start rejecting your continuous thermal load to the ambient with whatever radiator you have it will pretty much stay rock solid no matter how hard you beat on it unless you sized some part of it completely wrong. Air water will ALWAYS have the better temperature damping, you just cant stuff enough aluminum into an a/a to make it compete with a reasonably sized a/w as far as thermal inertia.

[dsm_gsx97]

Dave Landry is the only local guy I know that runs a LAIC. I have vids of him running low 11s last year on my site and here is some pics of his setup...You'll have to go on RMDSM to talk with him about it though. Everything except the core is custom on his setup.

http://dlandry.rmdsm.org/index.php?set_albumName=album07&option=com_gallery&Itemid=&include=view_album.php

I almost went to a setup like this but the money for it all and the work involved was more than I wanted to deal with at the time. To me it's a little pricey still while I'm working out my other kinks.

[D Walker]

Jacks brother Kevin has run LAIC for years now in his galant, Scott Seevers also ran a a LAIC in his GSX, and there are others.

[dsm_gsx97]

Jacks brother Kevin has run LAIC for years now in his galant, Scott Seevers also ran a a LAIC in his GSX, and there are others.

Well I was mainly speaking of someone who had pics available and could actually answer some questions of others since it was a question. Not that those guys couldn't, but when is the last time you've seen either of them on a forum?

Seevers switched that out 2 years ago to a FMIC since it was outlawed in the heads-up classes by the NHRA at the time. Is he even running anymore? He's been out as long as I have I think.

[thiazole]

So here are some calculations to digest:

If you had 1 gallon of water that was circulated through the intercooler without a radiator to cool the water back down, how much 300*F air could it cool to 100*F before the water's temperature increased 20*F?
300*F = 422K
100*F = 311K
20absolute*F = 11K
Cp Air = 1.0 J/(gK)
Cp water = 4.18 J/(gK)

So, it is easy to conclude that 1g water will rise 1K when cooling 1g air 4.18k.

1 gallon of water = 3785g water
3785g water could then cool 3785x4.18 = 15821g air 1K when rising 1K, or could cool 15821x11 = 174031g air 1K by rising 11K. To cool air 422K-311K = 111K, 1 gallon of water could handle 174031/111 = 1568g of air if allowed to rise 11F itself.

1568g = 4.2lbs of air. Therefore, if an engine is flowing 40lbs/min air, it would take 10 seconds and 300*F air to warm the water 20*F if the water was also cooling the air from 300*F to 100*F. Without back calcuting it, running the 1/4 mile on a system with 1 gallon of water and a 40lbs/min turbo pumping out 300*F air would only raise the temp of the water about 25*F. Now, assuming you have a radiator for the water and a 3 gallon tank, it is hard to imagine conditions that would overheat the water even if the radiator was inadequate to keep up. If the radiator pulled out only 50% of the heat created (I know it would become more efficient as the water got hotter, but for the sake of this example, we will assume the worst), a 3 gallon system would take 150 seconds of nonstop 40lbs/min 300*F air to warm the water by 50*F.