Water to air intercooler ideas

[Simon]

Also here. These guys have some spectacular kit for not bad prices.

http://www.frozenboost.com/

[Yowzer]

I'm modifying the old AC radiator in my car for use on the w2a system.

I think it's large enough, and it currently serves no other purpose.

[Hemi]

the condenser .

always been keen to try out a w2a system . just seems a bit more complicated and a few more parts and thought has to go into it .

[coldturkey]

sweet excuse my ignorance, wasn't trying to be a dick or anything but just didn't quite understand.

So effectively you are going air > water > air. I would have thought cutting out one step and going just air to air (i.e standard) would be more effecient but I guess there must be a reason for the water step, im no process engineer

Yeah water has a much higher thermal conductivity, and thus much better for heat transfer but surely you are cancelling this out if you are just going back to cooling air?

Anyway sorry for hi-jacking thread

[Roman]

Think of it this way... Why are most engines water cooled, and not air cooled?

[Yowzer]

Saves on trying to run 3" piping all around the front of your car. 1" heater hose is a shitload easier to work with.

[Yowzer]

Think of it this way... Why are most engines water cooled, and not air cooled?

For more even cooling of the internals. It is hard to get even airflow over a weird shaped object.

Radiators don't have this problem.

[Simon]

Haha.

Sorry for sounding abrasive. My "essay style" of writing can come off as me ripping into people. I need to think about rainbow pony before I write replies and add extra lols, hahas and :P's.

It's very efficient. Water has 4 times the specific heat capacity of air (even though the air isn't recycled) and like 25 times the thermal conductivity.

Especially efficient on road cars where you are not boosting much as the water has time to cool and doesn't really heat up but also a blat from an intersection / start line has full cooling where as an external IC needs lots of airflow under boost.

= Statement, explanation, expand/explore.

*facepalm*

[coldturkey]

Think of it this way... Why are most engines water cooled, and not air cooled?

Like yowser said, cause you are trying to cool a big thing and its easier to transfer it around, rather than air through a 3 inch cicle. I kinda get where you are coming from though.

Little bit different though, cause water to metal heat transfer is a lot easier than water to air, like I said, it would make more sense to me if the reason was to cool the turbo directly

[Simon]

Think of it this way... Why are most engines water cooled, and not air cooled?

Like yowser said, cause you are trying to cool a big thing and its easier to transfer it around, rather than air through a 3 inch cicle. I kinda get where you are coming from though.

Little bit different though, cause water to metal heat transfer is a lot easier than water to air, like I said, it would make more sense to me if the reason was to cool the turbo directly

Cooling the turbo is trying to cool the process. You're not interested in the process (compression) but the reaction (air).

The turbo doesn't go into the motor. The air does. That's why you have to cool the air - it's a system input.

I guess that's what you mean by "cool the turbo directly"?

It's all about heat transfer. Getting heat energy away from the air as quickly as possible. So with W2A you have hot air>alloy>water instead of hot air>alloy>air. I could show with heat transfer coefficients but not sure I need to / it's bed time.

Pretty much it's easier to get heat away with water than air.

Assuming of course that your heat exchanger in the front of the car is big enough to return the water at a temp close to ambient although IRL they do get a bit hotter.

Compressed air from the turbo can be up to 100 degrees in some cars, so if the returning water is like 10 degrees above ambient temp then you will still get a great heat exchange.

[Testament]

The reasons for water to air are application specific when compared to air to air

In a steady state air-air has the posibility to be more effective (to use correct HX terminology) as you are only going through one heat exchange

BUT

as said water has a hugely higher heat capacity - which means in transient conditions it has the possibility of being more effective than air to air .

you have this volume of water which you can conduct heat to better and it can absorb a significant amount of heat before reducing too much in effectiveness.

so in short burst of boost type applications such as normal road driving for drag racing a w2a setup has the possibility of being more effective.

also in drag racing you can use an icebox to make the water extra cold and improve things further.

it can aslo be good for low speed high load applications like offroading where an air to air intercooler does get much airflow and making it larger enough for natrual convection to be sufficient is not practical (you can get a better/more compact radiator/fan setup than air-air intercooler setup generally speaking)

Finally the other benefit is packaging - if you cant fit in a nice front mounted air-air setup it is often easier to mount a small radiator and then route the comparatively small and flexible water lines than large diameter intercooler piping with large radius bends. the w2a core can be more compact with lower pressure drop than an equivalent air-air core also.

the cons are the complexity and weight, in a race car on a circut or rally stage there is alot more sustained boost and repeated boost situations giving little time for a w2a system to reject the heat unless you put in a really large radiator - which only increases weight, the enemy of racing cars. also its one more thing to go wrong (pump, morelines etc. etc.) another thing you dont really want in a race car. I have first hand heard/ felt the effects of air locks causing poor pumping in a w2a system leading to limited heat transfer and very quickly to detonation - eventually leading to ruining a motor.

so to sum up if you can fit air-air in a position with decent airflow I would generally go with it unless you want an icebox setup for drag racing or its a 4x4.

[anglia4]

Thanks for that testament.

I'm building the car as a race car these days so that was great info. I had hoped to set it up with a W2A setup to save space coz the engine bay in the anglia is tiny!

Do you think you could keep the water temp under control with a fan on the radiator?

[Testament]

if its a race car I would really go air to air. ok an anglia doesn't have the most front end space, but Im sure you can find some way/where to fit one, even if you have to go with a custom core so get creative with sizes end tank designs if necessary.

[JoKer]

water to air is good for drags : except for added weight

race yea air to air

or none!

skids at tui on sunday so I prepared something spechil

[efp0wa]

Saves on trying to run 3" piping all around the front of your car. 1" heater hose is a shitload easier to work with.

So you would run 1" hose off the turb and into the throttle??

[Yowzer]

Shit yeah. All this large diameter piping is just a marketing scam.

[Llama]

Use Stirling engine in reverse powered by the exhaust gasses to do both the intercooling and compression.

Epic win.

[Sisu]

I have seen a couple of custom water to air intercoolers. This normally consists of an inline radiator in between the turbo and the manifold. The fluid is pumped around by an electrical waterpump to a radiator somewhere else more convienent with space which was sometimes underneath or even at the back of the car in the difuser.

With an Anglia you have that big guppy mouth behind the grill for the radiator and nothing else. You could run a pair of side mounted intercoolers, only consideration is that you would need to cut holes in the radiator duct in front and perpendicular to the radiator with the hot air exit into the front wheel well. As long as the radiator for the engine and the intercoolers are sealed(placed against the duct) then the air will be forced into the radiators evenly, air like water takes the path of least resistance. With the front grill/trim on it wouldn't be visable from the outside of the car.

This example is off an Audi. They need to reduce the front overhang, but have a similar problem with space.

[Mr Revhead]

Heating up the cooling water would say to me your system is too small or inefficient.

Different applications will differ but they don't need a lot of water to stay cool.

I used a Subaru rad and exchanger on my AW11. Granted not super power and the lines front to back gave it a bit more capacity but even on a 30+ deg day and a back road thrash the intake was still cold to the touch and the exchanger the same.

However I too would go for a A2A in a race car if allowed as the main benefit I feel in W2A is a more stable intake temp in vaired driving conditions. Whereas a race car only needs to work flat out with lots of air flow.

[H05TYL]

This example is off an Audi. They need to reduce the front overhang, but have a similar problem with space.

Intercoolers plumbed in series... interesting, I'd have thought they'd be plumbed in parallel.

It's not quite clear in that diagram, but all the properly ducted intercoolers (and radiators, oil coolers, etc) I've seen in production Audi's, Porsche's, etc have the inlet to the duct only 1/3rd to 1/2 the size of the core itself so the airflow slows through the core (more time for heat transfer to occur? lower pressure/temperature?) then the exit duct rapidly narrows to 1/3rd or 1/2 the size of the core to speed airflow before it exits the vehicle.