S/C Intercooler ?: Air-air vs. Water-air

[FordNut]

Another ?, Why do the MM centrifugal blower systems use Water-air intercoolers? All the ricers seem to be using use air-air, and I believe the Mach1 ProCharger system uses air-air.

[TAF]

What...you lose big at the craps table tonight...get sent to your room...and now, you've got all these questions?:baaa: :D

OR...while you and your lovely wife were driving around for hours the past few days...and she was saying "Oh, look honey...isn't that beautiful over there?" You were daydreaming about further mods to your car.....:shake: :( ;)

[FordNut]

What...you lose big at the craps table tonight...get sent to your room...and now, you've got all these questions?:baaa: :D

OR...while you and your lovely wife were driving around for hours the past few days...and she was saying "Oh, look honey...isn't that beautiful over there?" You were daydreaming about further mods to your car.....:shake: :( ;)
Naw, man it's just research that's all.

Shhh!, wouldn't want a spy sneaking around with a miniature digital camera now, would we?

[TripleTransAm]

I imagine air-to-air would require the intercooler to be situated right in the path of cool(er) air, whereas I suppose a water-to-air unit could be mounted anywhere? Small FWD cars typically have minuscule radiators so they might have enough room for an air-to-air unit up front. Just my wild a$$ guess...

[David Morton]

When I worked for Chevrolet in 1991 they had a one year option for the Caterpillar intercooled turbocharged 6.6L diesel in medium/heavy duty trucks. It was an air-to-air unit and it was bigger than the radiator, a good 2-1/2' X 3' X 4"! Redline was about 3600 rpm. Do the math, a 4.6L engine doing 6100 rpm would need something at least as big and need very exotic plumbing.

Besides, water does a better job in the thermodynamic heat transfer business. It's why the engines aren't air-cooled.

[Constable]

^^ Not true with modern coolers ^^ Although you will see that high performance intercoolers for modern turbo-diesel trucks are huge. Most of todays intercoolers and aftercoolers are very efficient and rather small.

Air to Air coolers are similar in design to trans coolers or oil coolers... the difference is that they cool the intake air charge instead of cooling fluids. When the car is at rest, there is no air flowing through the intercooler (or aftercooler). The air charge is then just normal engine-bay temp air.

Water to Air coolers use a resevoir with a coolant type liquid that chills the air charge flowing through it. Now, after a while, this fluid may warm up too. That is why you see these systems using "heat exchangers" as well. The heat exchanger mounts in a direct path of air. It cools the water temp, which eventually will be used to cool the intake air charge.

I'm not an authority on this stuff, but I hope that helps. I really think that air to air and water to air offer about the same results. The reason ricers use air to air is because they don't have enough room in their engine compartments for a resevoir, heat exchanger, the water-to-air cooler, and all the piping.

[BillyGman]

according to my studies, air-to-air intercoolers DO require more room because of their size. And it's been my understanding that this is the reason why we need water-to-air intercoolers for our Marauders. But I cannot say that I'm familair w/all of the foreign S/Ced vehicles, nor w/the intercooler systems that they use.
So for all I know, Constable might have a point. I really cannot say for certain.

[sailsmen]

In theory Air to Air is more efficient because the water in an Air to water is always above ambient temp.

Air to Air does require good flow and are bulky due to the need for a large internal flow area.

Water has a greater heat-transfer coefficent then air. The Air to water takes up more room due to the plumbing, reservoir and the need for 2 heat exchangers,but it does not all have to be mounted under hood.

[BillyGman]

The total amont of space required for the water-to-air system might be greater, however that doesn't present any problem (atleast w/the Marauder) since much of that extra space required is for the plumbing, and the plumbing hoses can fit in tight areas.

Because an air-to-air system requires a large heat exchanger to be efficient, that can present a problem since it's challenging to find a space big enough for such a large heat exchange unit, that is uncluttered to allow the airflow that would be required for it. So even if the overall space needed for an air-to-air intercooler system might be less than that of the total overall space required for a water-to-air system, the main bulk of that required space needed for the air-to-air is needed all in one area for the large heat exchanger that would have to be used. And it has to be somewhat free of clutter to allow enough air/flow to get at it. Whereas the plumbing and other various components of a water-to-air system obviously doesn't need air flow since it relies on water for cooling. And that to my knowledge would make the chances of having an efficient air-to-air under the hood of a Marauder very slim.

[427435]

First, let's get the terminology straigtened out. If we're talking about cooling inlet air, than the coolers are either air to air or air to water----not water to air. Water to air is what the car's radiator is. Although water is more efficient at transfering heat, the only good source is the car's cooling water---which will likely be 180 degrees or warmer. However, that can be a lot cooler than compressed air from a supercharger. I've never seen a system that cools the engine inlet air with an air to water cooler that includes a separate water to air cooler (other than the vehicle's regular radiator) to cool the water. If you stop to think about it, in the end, you're still moving heat from the inlet air to ambient air----you're just moving the heat to some water first and then to ambient air anyway----so why not just do an air to air and be done with it.

I suspect the systems that are using radiator water to cool engine inlet air are systems with a lot of boost (thus air temperatures at 250 degrees and up) or systems that just didn't want to (or couldn't) find room for an air to air cooler.

The reason HD diesel engines use air to air coolers is that it is the best way to go and they make sure they have room for them.

[sailsmen]

I beleive both the Tirlogy and Reinhart kits use a system separate from the engine cooling system with their own separate heat exchanger.

[jfclancy]

I beleive both the Tirlogy and Reinhart kits use a system separate from the engine cooling system with their own separate heat exchanger.

Well far from an expert I am , BUT seems to me when I looked at Logan's system there was a seperate container he said was the resovoir for the S/C
cooling system.

Joe Clancy

[FordNut]

I beleive both the Tirlogy and Reinhart kits use a system separate from the engine cooling system with their own separate heat exchanger.


Well far from an expert I am , BUT seems to me when I looked at Logan's system there was a seperate container he said was the resovoir for the S/C cooling system.

True, both systems have a reservoir and pump, I believe they both have two heat exchangers also. One air-water one to cool the water with ambient air, another water-air one to cool the compressed air between the supercharger and intake.

But unless I am mistaken the ProCharger kit for the Mach1 has an air-air exchanger without the pumps, plumbing, etc. The pics I have seen on the Pande's setup look like their ProCharger kit has a water reservoir, so it has been setup the same as the others. Maybe the Mach1 exchanger won't fit in fromt of our radiators? Or the plumbing is so much different that it is easier to convert to water? I better ask Bbockstanz I guess.

Edit: correction, since the "standard convention" is from higher temp to lower temp, the supercharged air goes thru an air-water heat exchanger, transferring heat to the water, which is then routed to the water-air heat exchanger in front of the radiator.

[the fat bastid]

Best analogy I've heard was take a hot frying pan and stick it in a sink of water and the water temp will rise.. take that same hot pan and wave it through the air and the air temp will barely budge. At the track the Aftercooler will have an advantage when used with ice. 0 boost loss and denser air. But just driving around the Air to air would definately be the better choice, water injection's an even cheaper alternative if you dont mind filling it every 500 or so miles.

donno if that helps

[MikesMerc]

Let's lay this to rest.

Most current intercoolers are now water-to-air designs. This means the hot compressed air coming from the SC or Turbo is run through the intercooler before it enters the cylinders. Heat passes from the very hot intake charge into the intercooler and into the fluid circulating through the intercooler loop. Heat is released by that loop into the air via the heat exchanger which is typically mounted on the front of the car.

The best intercooler designs use a seperate intercooler loop that never see engine coolant type temperatures. Good intercoolers set up with thier own reservoir and a decent heat exchanger rarely see water temps much above ambient.

Air to air intercoolers allow for the hot compressed charge from the turbo of SC to enter a large heat exchanger before entering the intake. Air to air heat exchangers are almost always large (certainly larger than the heat exchanger on a air to water intercooler). This is for several reasons.

Most importantly, in an air to air set up, all the heat gets passed into the atmosphere through one heat exchanger. Although water is a much better way to conduct heat, the air to air coolers are effective because of the temperature delta between the charged air and ambient air. The most important rule to remember is the higher the temp delta, the more efficient heat transference takes place.

Another very important reason that air to air coolers are large is due to the need to not bottle neck the boost. You cannot plum super high CFM through a tiny heat exchanger without huge boost pressure penalties. If you make the fin design within the air to air heat exchanger less restrictive, you give up cooling do to less surface (fin) area.

Air to water is almost always more efficient than air to air unless it is poorly designed. With the air to water intercooler, you have water (with much better temperature conductivity) transferring the heat from the intercooler into the fluid, and again from the fluid into the heat exchanger. Even though the temperature deltas between the compressed charge and the intercooler temp, and the fluid temps versus ambient air, are smaller than in an air to air set up (so you loose efficiency with the smaller deltas), the benefit of the thermal tranference properties of the fluid far outwiegh the loss of efficiency.

Bottom line, on street cars, air to water is the way to go. They can remove far more heat from the boost temps with space limitations. The only way you'll get an air to air to compete is with a much larger system which inlcudes large plumbing and heat exchanger so as not to kill the boost and provide for more surface area for thermal tranference without the aid of fluids.

[BillyGman]

Well far from an expert I am , BUT seems to me when I looked at Logan's system there was a seperate container he said was the resovoir for the S/C
cooling system.

Joe Clancy
Exactly. The Trilogy sytem does NOT use the engine coolant. It has it's own radiator, resovior, and electric waterpump that are ALL separate AND independent form everything in the engine's coolant sytem. So I'm glad that we got THAT straight.

[Jerry Barnes]

Mike and BillyG are correct. We looked at several alternatives and the most effective and efficiat is the water-to-air intercooler. Studies at Ford and other OEM indicate that air-to-water is the best. Air-to-air is O.K. but brings many limitations that would make tolerances, performance, climate changes and other factors become issues. That is why we selected the solution we did for our kit.

Thanks guys for the very good explanation. And yes our system uses seperate intercooler, radiator and water pump, not tied to the engine cooling system.

Nice job Mike and BillyG!

[Dennis Reinhart]

OK here is my opinion about water to air/air to air after coolers both have there plus and minus, first of all with an air to air you must have a larger heat exchanger to transfer heat quickly or the engine will run a higher ACT air charge temp or IAT intake air temp. The air to air heat exchanger is just like the cars AC condenser, the supercharger or turbo charger compresses air which in turn cause the air temp to rise as much as 150 degrees or more over out side air, this hot air will cause spark knock and detonation, hopefully the knock sensors will pull enough timing to prevent damage, and with the increase in IAT the engine will make less power.

Now with the air to air heat exchanger if its not located right, it will effect the efficiency of the cars AC condenser and radiator if its placed to close to the AC condenser all the heat coming off the S/C heat exchanger is passed on to the AC condenser and Radiator which is directly in front of it. Also with an air to air if the car is in traffic the IAT will rise rapidly, it has to have air passing over its coils.

Now with a good water to air setup the cars IAT should be close to about 15 degrees over out side air, my kit runs 10. I use a large 2.5 gallon reservoir
http://web.iwebcenters.com/reinhartautomotive/images/Mvc-048s.jpg

Some companies use transmission coolers and the put electric fans on them, I use a large condenser that was designed to flow water
http://web.iwebcenters.com/reinhartautomotive/images/heatexch.jpg.jpg

The after cooler replaces the stock air box this car made 585 with 18 PSI to the tires and the IAT runs 13 degrees over out side air
http://web.iwebcenters.com/reinhartautomotive/images/STUENG1.jpg


I put the tank in the fender well out of the heat build up that can come if its under the hood, if you use to small of a reservoir the water can be heated up and will take a lot longer to cool down. With my setup I can even add ice, what I have done is take the cars OAT = out side air temp sensor and place that sensor in the discharge or inlet to the TB with the press of your AC button out side air temp, you can read the actual air temp entering the intake my system runs about 10 degrees over out side air, this is as good as you can get, and with in ten minutes of driving the car will stabilize at this temp, and if you are setting at the track or in traffic the water pump is constantly circulating water. So its what ever floats your boat some like air to air and others like water to air for a daily driver I think water to air is better.

http://www.mercurymarauder.net/banners/adimage.php?filename=rbanner.g if&contenttype=gif

[sailsmen]

Awesome set up! :up: