I was reading the end of Forced Induction Performance Tuning (I like this book more than Maximum Boost, BTW) and the author used a water-to-air intercooler in a project Subaru towards the end. He cited the many benefits of this design for this particular engine layout, all of which made good sense.
Subaru itself used to use a water-to-air intercoolers in the 90's. I realize their water-to-air intercoolers were not that great (small core, 15l/m pump), but with larger cores, they could have been vastly improved designs. Instead, Subaru took a step backwards with their current top-mount "interwarmer" design.
So why hasn't the aftermarket picked up the slack?
It seems STI owners consider front-mount intercoolers the holy grail of intercooling, but with all the six or more feet of additional (hot, engine bay) plumbing it requires on this car, I don't see it that way. Too many compromises are made that simply aren't there with a water-to-air design. I think front-mounts make perfect sense on the Evo, but unless you're relocating the turbo and rotating the intake manifold, a water-to-air intercooler makes more sense for the STI.
A water-to-air intercooler combines the cooling capacity and resistance to heat soak of a front-mount with the small volume and quick spool of a top-mount. It truly is the best of both worlds (and then some), with the drawback being expense. However, front-mount kits are already expensive (due to the required piping?), and I suspect a water-to-air unit would not be much more.
The benefits are both direct and indirect: for example, a compact WTA unit would not necessitate the use of a warm air (short ram) intake the way many front-mount kits do, so the intercooler would have a cooler charge to start with. Running a front-mount intercooler with a warm-air intake is rather silly, IMO, as you end up getting drastic heat soak anyway. Furthermore, because water-to-air intercoolers are more compact, it would not require the cutting or removal of front fender pieces (as most front-mounts do). The installation should therefore be much simpler and more easily reversable.
Furthermore, I think the STI already has one of the components of a water-to-air unit installed. Because a water-to-air intercooler would render the intercooler water spray tank somewhat useless (it wouldn't heat soak), that tank could be reused as a large intercooler reservoir. Because it is mounted away from the heat of the engine bay, it could work great. If filled with ice, it may be large enough to keep one's intercooler efficiency above 100% for most of a 20 minute track session. Drag racers would certainly love this too.
A few attempts have been made before, but none have succeeded. Here's a thread I found on Nasioc. People got really, really excited but this kit (developed by some guy in Pennsylvania) never came out:
http://forums.nasioc.com/forums/showthread.php?t=796049
Here's a thread on another waiter to air intercooler from a different company. It's very expensive and the company is not in the USA:
http://forums.nasioc.com/forums/showthread.php?t=776570
And, for those thinking, "WTF is a WTAIC?" here is some good reading on water-to-air intercoolers:
http://www.mr2supercharger.com/IntercoolingPage5.html
And, for fun, here's a water/air intercooler on a Subaru:
![Image]()
![Image]()
Two more pictures of different, custom designs:
http://www.we-todd-did-racing.com/wetoddimage.wtdr/wOTAwNTk4NnM0MTNkZmQzMXk1NDE=.jpg
http://img.photobucket.com/albums/v204/cbrd/newturbo007.jpg
Unfortunately, I don't know much about the kits pictured above. Hell, try searching for a water-to-air intercooler here and the results will be surprisingly short. I'd like to get people talking about them again.
With a plethora of front-mounts to chose from, why aren't there any serious water-to-air intercoolers on the market? I've already approached a company with the idea, and while we were both excited about it, we were left wondering why water-to-air intercoolers aren't popular already. Is it from lack of demand or lack of supply? Because Subaru used to use the water-to-air intercooler in the 90's, this is not at all a new concept!
Subaru itself used to use a water-to-air intercoolers in the 90's. I realize their water-to-air intercoolers were not that great (small core, 15l/m pump), but with larger cores, they could have been vastly improved designs. Instead, Subaru took a step backwards with their current top-mount "interwarmer" design.
So why hasn't the aftermarket picked up the slack?
It seems STI owners consider front-mount intercoolers the holy grail of intercooling, but with all the six or more feet of additional (hot, engine bay) plumbing it requires on this car, I don't see it that way. Too many compromises are made that simply aren't there with a water-to-air design. I think front-mounts make perfect sense on the Evo, but unless you're relocating the turbo and rotating the intake manifold, a water-to-air intercooler makes more sense for the STI.
A water-to-air intercooler combines the cooling capacity and resistance to heat soak of a front-mount with the small volume and quick spool of a top-mount. It truly is the best of both worlds (and then some), with the drawback being expense. However, front-mount kits are already expensive (due to the required piping?), and I suspect a water-to-air unit would not be much more.
The benefits are both direct and indirect: for example, a compact WTA unit would not necessitate the use of a warm air (short ram) intake the way many front-mount kits do, so the intercooler would have a cooler charge to start with. Running a front-mount intercooler with a warm-air intake is rather silly, IMO, as you end up getting drastic heat soak anyway. Furthermore, because water-to-air intercoolers are more compact, it would not require the cutting or removal of front fender pieces (as most front-mounts do). The installation should therefore be much simpler and more easily reversable.
Furthermore, I think the STI already has one of the components of a water-to-air unit installed. Because a water-to-air intercooler would render the intercooler water spray tank somewhat useless (it wouldn't heat soak), that tank could be reused as a large intercooler reservoir. Because it is mounted away from the heat of the engine bay, it could work great. If filled with ice, it may be large enough to keep one's intercooler efficiency above 100% for most of a 20 minute track session. Drag racers would certainly love this too.
A few attempts have been made before, but none have succeeded. Here's a thread I found on Nasioc. People got really, really excited but this kit (developed by some guy in Pennsylvania) never came out:
http://forums.nasioc.com/forums/showthread.php?t=796049
Here's a thread on another waiter to air intercooler from a different company. It's very expensive and the company is not in the USA:
http://forums.nasioc.com/forums/showthread.php?t=776570
And, for those thinking, "WTF is a WTAIC?" here is some good reading on water-to-air intercoolers:
http://www.mr2supercharger.com/IntercoolingPage5.html
And, for fun, here's a water/air intercooler on a Subaru:
Two more pictures of different, custom designs:
http://www.we-todd-did-racing.com/wetoddimage.wtdr/wOTAwNTk4NnM0MTNkZmQzMXk1NDE=.jpg
http://img.photobucket.com/albums/v204/cbrd/newturbo007.jpg
Unfortunately, I don't know much about the kits pictured above. Hell, try searching for a water-to-air intercooler here and the results will be surprisingly short. I'd like to get people talking about them again.
With a plethora of front-mounts to chose from, why aren't there any serious water-to-air intercoolers on the market? I've already approached a company with the idea, and while we were both excited about it, we were left wondering why water-to-air intercoolers aren't popular already. Is it from lack of demand or lack of supply? Because Subaru used to use the water-to-air intercooler in the 90's, this is not at all a new concept!
