Dual intercooler system

Hi there,

I am new on here and am looking for some advise.
I am thinking of fitting a charge cooler (water to air front mount system) with the standard stock system (air - air) as well.
Both will be working at the same time.

Is this a good idea ?

I am also running alot more boost.

Thanks for you comments

Game-On

you can count on some major turbo lag thats for sure, but i guess it will work.

On a street system, an air-air and air-water unit will provide about the same cooling capacity. So you probably will gain very little cooling capacity from running both. You may lose some power due to the higher pressure drop and you'll certainly experience more lag. I'd suggest either just replacing the air-air with an air-water, so you can add ice water and run quicker for a short ammount of time(until the ice melts), or just get a larger/more efficient air-air unit.

Operating efficiency of a water-system is way worse than an ait-air system. That's why you don't find any water based systems in racingcars (except dragracing and similar). However, a water based intercooler was used by Renault in F1. It used the engine coolant to reduce the air temperature down to slightly above coolant temperature. Then an air-air intercooler takes over allowing a small package for a high boost application where temperatures of the pressurized air are well above 100 degC.

Operating efficiency of a water-system is way worse than an ait-air system.

Why is the operating efficiency worse for the water-air system? Is it because it is a closed system and the water must be cooled. While the air-air is an open system and the cooling air need not be ‘conditioned’.

Also, doesn’t the significantly higher heat capacitance of water offset the inefficiency of the system? Well at least for certain applications?

Air-water should have approximately the same heat-reducing efficiency as a air-air, with less core pressure loss due to the reduced core area required. As long as you have a heat exchanger to cool the water again, it should have about the same efficiency as an air-air unit. The advantages of air-water are the ability to put colder than ambient air temp water in the system and achieve higher efficiencies(100+% is possible), and the reduced core area tends to mean less pressure loss through the core and slightly less lag(less volume to pressurize). Advantages of air-air is they're MUCH simpler systems, and offer good cooling capacity. Air-water is overly complex for a street application, but if you want that extra cooling capacity for the drag strip, its worth it.

The advantages of air-water are the ability to put colder than ambient air temp water in the system and achieve higher efficiencies(100+% is possible)

I understand that its not difficult to get a high fin efficacy, but 100%+ system efficiency how is that achieved?

I understand that its not difficult to get a high fin efficacy, but 100%+ system efficiency how is that achieved?

Intercooler efficiency is based on air temp before intercooler, air temp afterwards, and ambient air temp. If you achieve after-intercooler temps which are lower than ambient air temperature, then your intercooler is more than 100% efficient. If you use ice water as a cooling medium, which is most likely colder than ambient air, you can achieve more than 100% intercooler efficiency.
Air-water intercoolers work best in boats, since water temperature is almost always lower than air temps. In a boat, an air-water intercooler is superior to an air-air.

Operating efficiency of a water-system is way worse than an ait-air system. That's why you don't find any water based systems in racingcars (except dragracing and similar). However, a water based intercooler was used by Renault in F1. It used the engine coolant to reduce the air temperature down to slightly above coolant temperature. Then an air-air intercooler takes over allowing a small package for a high boost application where temperatures of the pressurized air are well above 100 degC.

Water/air systems are more efficient than air/air systems. You dont find water/air systems in race cars because of the extra wieght needed to run a water system, pumps, a front mounted radiator to cool the coolant as well as the charge cooler, the wieght of the coolant itself etc etc
and as mentioned the water/air has less induction pipework so there is less turbo lag, and water has greater heat capacity to remove more heat away from the intake air.

LOL, WRONG.
If you have a 7hr race and your engine is running at high RPM's the entire time you will be flowing alot of air. The water just keeps getting warmer and warmer. a little tiny transmission cooler sized radiator isnt going to be able to keep up.
Now if you put in some water/antifreez mixture that is say 10 degrees F into the system directly before a drag race you will see amazing intercooler efficency. Air-Air transer can only cool the incoming air to the ambient air tempature. most intercoolers work anywhere from 50-80% efficency many around 70%. Sure a Water-air intercooler may start a race with 90% efficency but as the water/antifreez heats up and the radiator cant keep up its efficency is hindered greatly. Weight isnt a big issue. these systems dont use much over 1-2gal. that is 8-16lbs TOPS. the driver can spare that by not eating for a while....

I think the issue is the added complexity of the system. Not to say a race car building team can't design one, its just one less thing to fail. If that water pump goes kaput, then you can't run full boost, which means you might as well drop out of the race.
A combination that, the extra weight, and the lost efficiency in endurance applications(although you exaggerate its effect CB, charge temperature should only raise maybe 8-10* from the beginning to the end with an appropriately sized front heat exchanger) leaves an obvious choice for endurance applications; air-air. For street/strip cars, its up in the air. For drag cars, air-water is clearly superior.

Pace are the company who are making this for me.
Like i said both systems will be in operation at the same time..
They said when it was fitted to a scooby they had improved HP as a result.
Also a kit for the cossy500

Yes i know about the down side of a water-air system.
Yes you are so true about the water temp when driving, but this is a road car not a 7 lap racer.
You dont often around UK get the space to open her up for more then an hour at a time.
I will have this dynoed before and after ill post the results

Game-on

Why is the operating efficiency worse for the water-air system? Is it because it is a closed system and the water must be cooled. While the air-air is an open system and the cooling air need not be ‘conditioned’.

Also, doesn’t the significantly higher heat capacitance of water offset the inefficiency of the system? Well at least for certain applications?
If I asked you which engine has the highest operating efficiency between a internal combustion piston engine and a steam engine I would guess your answer would be the internal combustion engine, which is also the correct answer.

So why is it so then? Well, when you burn coal in the steam engine the coal burns at a very high temperature. And the laws of physics say that the greater temperature difference you got between a hot and a cold source the greater the efficiency can be. So if the energy could be transfered directly with the coal (or gasoline) burning at more than 1000 degC would be a better solution than using overheated steam at perhaps 150 degC. If the medium you're using have a really high heat capacity doesn't matter.

This theory can be applied on a lot of things, for examples newer jet engines operate at much higher temperatures for increased efficiency and performance. It can also be applied to a cooling system.

If you got a water based system, the air must first be cooled with water, the water will know have a temperature lower than the air has. This water will then be cooled by onother flow of air, but the temperature difference will be lower than if we had cooled the air directly, and thereby we have reduced the efficiency of the system. Not to mention that we have also increased the weight and size of the package.

When water based intercooling systems are used in cars for the street these are usually build to cool the air for a short period of time like when accelerating for perhaps 10 or 15 seconds. Under this period the water in the system is heated, but the actual cooling of the water takes place later when the engine is off boost. The intercooler itself will then act as a radiator and the need of a radiator for the system is small, typically a small oil cooler can serve the purpose. Cooling of the brakes on a car works in the same way, you brake, motion turns into heat which increases the temperature of the disc. The disc then acts as a buffer which can hold this heat for a short period until the cooling system can take care of it.

Rules of thumb from a resource I have:

25% steady running (more than 30s) air to air
50% quick acceleration air to air
75% air to water
100% air to cold water
125% air to ice water

big diesel power units use jacket water in air to water aftercoolers but they are running 30psi or more of boost and 160F water provides lots of cooling to the high discharge temps in one of these engines.

May not be 100% correlation but in the world of high power semiconductors water cooling is much more effective than air cooling. 80C water will pull more heat from a semiconductor than 40C air even if it is a tremendous volume of air. This is with water cooled by the same air that could be blown over the heatsink which is why the water is allways hotter than the air.

How many air cooled engines do you see out there?

I think IN GENERAL air to water is more effective. I don't see any advantages of combining the two that outway the disadvantages. If there is an example of increased output by adding one in combination with the other (like adding an air to air to an air to water), I feel it was because the air to water was undersized and the addition of the air to air just increased the capacity and the same could have been achieved by increasing the air to water system.

Rules of thumb from a resource I have:

25% steady running (more than 30s) air to air
50% quick acceleration air to air
75% air to water
100% air to cold water
125% air to ice water

big diesel power units use jacket water in air to water aftercoolers but they are running 30psi or more of boost and 160F water provides lots of cooling to the high discharge temps in one of these engines.

May not be 100% correlation but in the world of high power semiconductors water cooling is much more effective than air cooling. 80C water will pull more heat from a semiconductor than 40C air even if it is a tremendous volume of air. This is with water cooled by the same air that could be blown over the heatsink which is why the water is allways hotter than the air.

How many air cooled engines do you see out there?

I think IN GENERAL air to water is more effective. I don't see any advantages of combining the two that outway the disadvantages. If there is an example of increased output by adding one in combination with the other (like adding an air to air to an air to water), I feel it was because the air to water was undersized and the addition of the air to air just increased the capacity and the same could have been achieved by increasing the air to water system.
Your rules are wrong. Water is less efficient unless you have a source of cold water like in boats.

There are however some real rules of thumb, but I don't remember them correctly but I think it was something like 50-60% for water and 70-80% for air, but the best thing with air-to-air is that it doesn't matter if it's a 10 second acceleration or a 24 hour endurance race, the cooling properties stays the same while the water based systems are usually designed for a 30 second boost until they becomes almost worthless.

Large diesels usually use a big air to air intercooler, unless you talk about marine engines or something like that.

Air with 40 degC will cool much better than 80 degC water if you have an unlimited flow. The lowest temperatures possible in these cases are 40degC for the air and 80 degC for the water (othervise the heat transfer will change direction). The problem with air cooling is just to fit cooling fins that are large enough and to build ducts for the air. The water is in that way a much more compact system even if there is a efficiecy loss.
The water can also act as a buffer.

In the electronics industry the heat transfer properties of a metal is often used. Some newer notebooks are fitted with this technology often called "heat pipe" which is basicly a piece of copper that transfers the heat away from the processor to cooling fins and fans placed somewhere else in the computer. Similar systems are used in electronic systems in space (first used in the lunar module), but then beryllium is typically usually used as the heat transfer material and the system is then "water based" as there is no air availible.
Fuel can also be used as cooling, for example the truck manufacturer Scania used the diesel fuel to cool the ECU, the fuel is also often used to cool components in rocket and jet engines. Oil is also often used for cooling, but mostly for higher temperatures or when both lubrication and cooling is wanted.

Those "heat pipes" are filled with a fluid that boils at low temperatures and those pipe are also under a vacume to increase the heat transfer abilities. Copper is alot heavier than aluminum...but i'm shure you could make it out of aluminum.

Those "heat pipes" are filled with a fluid that boils at low temperatures and those pipe are also under a vacume to increase the heat transfer abilities. Copper is alot heavier than aluminum...but i'm shure you could make it out of aluminum.
The old systems just use the heat transfer of the metal, I assumed the newer ones did too; I guess they don't.

Using the heat of vaporisation and the thermosiphone effect will be a much better way to transfer heat, almost without temperature loss.

After you do a run and the water is heated up, how is it going to be cooled again? Yep, air. You would basically have to run a small radiator down in front of the car to cool all that water after a run. Plus you need a pump of some sort. I've heard of using engine coolant. Not sure on how well that would work.

Air-to-air are the way to go on the street. Tried and true.

For a well engineered air-to-water system, check into the system that Lotus used on the 89+ Esprit. The efficiency claimed is 69%, sustained.
Pre-chargecooled, the car ran a very iffy 10lbs. boost. It now runs a reliable 18 lbs. boost.
For some close in pics, see my car in the gallery.

I have an idea!! Get a bigger air-to-air intercooler and don't worry about the rest of it. I don't think you'll gain anything by running a charge cooler and an air-to-air intercooler, you may actually lose efficiency by doing that.

IMO, bigger air-to-air intercooler and forget the charge cooler.