hi i was looking for parts to do research for fabricating a water-to-air intercooler and stumbled upon this forum... i realized that i had some information to possibly help clarify some of the info on this thread..

first off there is no perfect intercooling system.. its just the nature of engineering you have to make comprises to get the best of what you want with loosing something in other areas...

first off a turbocharger works by taking hot exhaust gases from the exhaust manifold and running a turbine.. a turbine takes the expanding hot exhaust gases and creates work.. the work generated by the turbine spins a shaft.. which powers the compressor side of the turbo.. the compressor takes air from the outside air and compresses it.. now according to the ideal gas law.. Pressure*Volume=Mass*Gas Constant*Temperature when you increase pressure you also increase Temperature.. now the goal of a turbocharger is to force more air into the engine.. not more pressure, or more heat.. but cool dense air.. so you want to increase the Mass part of the equation.. basically a turbo makes a smaller engine perform like a much larger engine that takes in more air...

now here is where the intercooler comes into play.. hotter air into the engine is bad.. first hot air is not as dense as cool air meaning less mass per volume(and volume is constant in your engine).. second hot air can cause detonation.. detonation is real bad.. it is when the hot air in the engine combined with fuel ignites before the spark plug sparks.. this is bad in many ways: 1) it impossible to time the firing of the engine 2) the piston is already being forced up by the crank.. when detonation occurs the piston is not necessarily in the right position to go back down.. meaning you have two forces acting in opposite directions on your piston, connecting rod, bearings, and crank shaft = real bad for life of engine..

how the intercooler works...
now an air to air intercooler is a heat exchanger, similar to a radiator, a FM is an air to air intercooler, hot compressed air coming from the compressor passes through the passages in the intercooler.. while this is happening cooler air from the atmosphere (same air the turbo's compressor sucked in and compressed) passes through the front of it and absorbs heat from the compressed air.. the maximum possible efficiency of an air-to-air intercooler is 100% (air was originally at temperature X when it was sucked in by compressor then compressed temp X+Y(from compressing) is what it is after turbo... air passing through intercooler is temp X so the best it can do is return to X the starting temp).. air-to-air intercoolers are best in road racing cars, some street cars, rally cars, other cars that run long periods of time.. the main draw back to air-to-air is the passage ways to get the air to intercooler require some space to be routed.. some cars do not have this space.. another problem is as you route the piping all the way to intercooler and back.. pressure drop will occur.. (fluid mechanics comes into play here: each bend, each diameter of the pipe change, each irregularity has an effect on the pressure) ...

water-to-air intercoolers use two heat exchangers.. one located in the intake track (this one removes heat from the intake air) and the other typically near the front of the car where it recieves cool moving air.. the water used in the intercooler is not from the main engine coolant (despite what is often believed ( I originally thought this)) however it comes from a seperate resevoir just for intercooling.. if the water did come from the engine, which is much hotter than the intake charge would ever get, then it would be an interheater... the advantages of a water-to-air are: 1) water has a much higher heat-transfer coefficient than air it is about 14 to 1 so the ability of the water to carry heat away is much better 2) the lines required for water to be routed to the front of the car can go any route one would please.. pressure drop doesnt matter here.. however it does require a seperate pump.. in cars with less space or funky intake layouts water intercooling is the way to go... with the ability of water to transfer heat better it is possible for water-to-air intercooler to achieve better than 100% efficiency in that the air can be cooled beyond what it was orginally before it was compressed, however this requires the use of ice or some other coolant.. (in turbocharged boats water-to-air is perfect with an abundant source of cool water) .. Drag cars are also ideal especially when ice, or other coolants (perhaps Liquid Nitrogen!) are used.. however ice and liquid nitrogen are consumables, meaning they only last so long and need to be refueled.. could get pricey and a pain in the ***.. many cars have been manufactured from the factory with water-to-air intercoolers(Lotus, Maserati, 198x's Mazda RX-7s Turbos.. ) and they work great for their applications..

so which is better.. depends on the application.. most likely Air-to-Air is best for street use.. however you may have a strange intake layout that would not lend itself to easy front mounting.. both are difficult to design and install if you are making either system on your own however water-to-air is far more complex... a good mechanical aptitude as well as some expierence in a shop would be helpful..

(i hope this helps, if its of any interest.. i am a 3rd year engineering student.. i am currently on a racing team.. and have taken many classes that have taught me alot about how thermodynamics, physics, and other engineering principles effect cars and turbochargers... so i didnt make any of this up.. for further info check out MAXIMUM BOOST by Corky Bell(Amazon.com carries it) its a great book with lots of info about designing, installing and testing all aspects of a turbocharging system)

 

what kind of a racing team? I used to be on a Formula racing team in college.

 

OKey DOKey. i dont think there will be many people interested in this

 

I am on a Formula SAE team.. The University of Akrons team to be specific...(we placed 7th last year in Detroit out of 140 ).. I also autocross an '85 Toyota MR2.. and drag race my '91 Eagle Talon TSI...

and King D.. what wont people be interested?? the correct and factual information i provided about both air-to-air front mounted intercoolers and water-to-air intercoolers which is what this thread is about in the first place.. ?

 

dude i covered that already. if you read the whole thread you will see i asked is anybody interested. i got no reply just critisism i ont know how you think but i know when to throw in the towel.

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Hey DSM_MASTER I was on the OSU Formula SAE team.

 

thats cool jestomen.. how long ago? they use a cool carbon fiber monoque now..

Sorrry King_D i didnt realize that you were David_K as well you opened the thread as David_K.. so i assumed David_K was interested..

 

its all good. jesty hasnt been in college since the 90s (hes old)

 

I was on the formula buckeyes team 4 or so years ago. We had just started using a carbon fiber tub. That was fun to build, lots of work involved!

 

yeah i wish i had a carbon fiber shower