Been thinking about my intercooler options for my accent... I know the convetional method is to use an FMIC, but there is very very little room in the front bumper of the accent, not to mention where to run the piping. I'm also not looking to cut holes into my hood. So what about a water-to-air intercooler... too expensive, or is it?

I was thinking to find a small air-air intercooler and enclosing it and making it into a water-air intercooler. I could use a tranny cooler for the radiator for it (i can get one for free). For the pump, i could use the stock 1.6L accent fuel pump, and run the pump off of its signal from the ECM that would give it more voltage, increasing flow, as load increases.

As for the heat soak problems i've heard water-air intercoolers have if you park for a few minutes... maybe rig up a fan and the pump on a timer circuit that will keep it running after i turn the car off for a few minutes or something... But i'll cross that bridge when i come to it...

 

There is plenty of room for a front mount air to air intercooler.

Also you are planning on using a smaller air / water radiator for a less efficient air to water intercooler. Air to water intercoolers are only more efficient for drag race conditions where you can temporarily use ice water... to improve the heat exchange.

There is no place for a air to water intercooler in a STREET driven TURBO car.

 

Why not? Water has a higher specific heat than air, so it can therefore draw more heat out of the same sized intercooler as compared with a normal air-air intercooler. With an additional heat exchanger on the front of the car, and the pump running continously, the majority of the water will not heatsoak, especially if I have a remote resevior for the water supply, say in the fenderwell.

Other than heatsoak and the slight difficulties of plumbing the system, what makes water-air worse than air-air? I know jackson racing uses a water-air as an add on to its supercarger kits, so something has to work about it. I've heard some glowing reports about it from people on miata.net who have street driven cars with it...

 

Of course it works. But look at the applications you are talking about.... tight spaced SUPERCHARGED cars.

1. You forget that with a water to air system you have TWO heat exhangers. The intake air to water exhangers and the water to ambient air exhanger. Both ineffeciencies multiply together.
2. Because of lack of room, the intake air to water heat exhanger is usually very small.
3. Usually if you can't mount a proper sized air to air intercooler, the water to ambient air heat exhanger is also too small.

So there you have it, TWO way too small heat exhangers.. with one sitting in the engine bay... with complete heat soak.

 

But with water's higher specific heat, i dont need such a large intake exchanger. Also, i have all the room leftover from the factory airbox and more to mount the water-air intake exchanger, so size there is again not a problem.

Ok, so the tib tranny cooler is a tad small... I can goto autozone and pick up a good sized tranny cooler for a F150 (or hell, hit the junyard), with fan for relatively cheap. The hoses and core of this are a lot thinner (think vacuum hose), which means i can mount this relatively easily up front as compared to a 2.5" intercooler core with its 2"+ hoses. I also think my idea with the water mostly stored in the fenderwell will help combat heat soak.

I think i'll try this way. Its not like i dont have time to think about it. Besides, if it doesnt work well i can always pick up a cheap air-air with some piping off ebay or a local junkyard. smile.gif

 

The cheapest form of a air/water aftercooler is taking a heater core and making a air tight box and flowing air through it and flowing water through the inlet and outlet tubes. It does work, if you want to invest the time to make it.

 

I think Cheuk's point isn't that the water can't hold the heat--it's the air side that is the problem. Although the water side can be much smaller, you still need a large amount of surface area on the air side to achieve the same heat transfer.

Unfortunately, air-to-anything heat exchangers are not very efficient in any case--I'm not saying your idea won't work, I don't have any experience with the setups and haven't taken the time to analyse the energy balances fully. But it seems to me(I haven't quite managed to forget those damn thermodynamics courses yet!) that if you were looking to run a water pump to do this you could also consider a small compressor--a small AC unit could give you similar benefits with better heat transfer properties. Vaporization of the AC fluid through a radiator coil provides much greater heat soak than only liquid phase flow. But that was just another passing thought, again I haven't given it enough time to determine its feasibility smile.gif

 

Just trying to save you some trouble. It is alot of piping and hoses and heat exchangers for something that in the end will be more of a headache, more expensive and less efficient than a air to air unit.

The only turbocharged car that I know of that uses a air to water unit is the older turbo Lotus.

Just find you a cheap air to air intercooler. Like the Isuzu NPR small intercooler. Look at this
web page

 

I didnt know you were on xceedspeed cheuk, then again i havent been back there for a while. Dont know what that link had to do with water-air IC's tho... BTW, the subaru legacy uses a water-air IC, and I think the older supra's might too... There are others too.

Everything i've read so far has indicated that water-air IC are more efficient, even when not packed with ice, esp this article off of autospeed.. The reason is (I know you know this cheuk and HRD, but i wanna rehash it for my and other's benefit) the intercooler acts as a heat sink, which is then cooled by ambient air. With a regular air-air IC, when you stop accelerating the IC throws some heat back into the intake charge, causing dramtic temperature spikes. With water-air, this is avoided as water's higher specific heat makes it more resistant to this temp spiking. The only thing that stops the widespread use of water-air is the higher cost and the plumbing, as well as a FMIC looks nicer, i thought. Maybe i've missed something...

Also, isnt all the plumbing the line from the intake exchanger--->resevior--->ambient exchanger--->pump---->intake exchanger? That doesnt seem to be all that complicated... Only electric wiring would be the pump, but since i'm converting to return fuel system, i'll have the stock fuel pump signal to run the pump off of. Possibly a small fan behind the ambient exchanger too... Again, nothing that seems too complicated. But again i'm probably missing something...

HRD- are you saying use the heat exchanger to carry the water or the air through the airbox?